{"id":512508,"date":"2026-03-01T20:54:19","date_gmt":"2026-03-01T20:54:19","guid":{"rendered":"https:\/\/www.newsbeep.com\/au\/512508\/"},"modified":"2026-03-01T20:54:19","modified_gmt":"2026-03-01T20:54:19","slug":"sub-1-volt-reconfigurable-gires-tournois-resonators-for-full-coloured-monopixel-array","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/au\/512508\/","title":{"rendered":"Sub-1-volt, reconfigurable Gires-Tournois resonators for full-coloured monopixel array"},"content":{"rendered":"<p>Concept of reconfigurable Gires-Tournois monopixels<\/p>\n<p>Reflective displays offer a compact and efficient design, leveraging external light without an internal light-emitting part. It is particularly advantageous for micrometre-scale displays, as it avoids significant challenges associated with optical efficiency degradation and fabrication yield, especially in pixel dimensions down to a few micrometres. Moreover, advancements in structural colour-based reconfigurable photonics facilitate monopixel functionality, obviating the necessity for subpixel arrangements and enabling the fabrication of extremely small pixel dimensions (Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#Fig1\" rel=\"nofollow noopener\" target=\"_blank\">1a<\/a>). Considering the required PPI for adequate image quality, which varies with the distance (d) between the display and the observer\u2019s eye based on general guidelines, a pixels per degree (PPD) of at least 60, is typically necessary to ensure continuous and high-quality display output based on 20\/20 vision standard<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 17\" title=\"Snellen, H. On the methods of determining the acuity of vision. Syst. Dis. Eye 2, 93&#x2013;98 (1897).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR17\" id=\"ref-link-section-d284866755e658\" rel=\"nofollow noopener\" target=\"_blank\">17<\/a>. Additionally, recent studies suggest that achieving maximum resolution for near-eye displays, such as those used in virtual and augmented reality (VR\/AR), may require a significantly higher PPD of over 90, necessitating pixel sizes as small as 2 \u03bcm, corresponding to ~10,000 PPI (Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#Fig1\" rel=\"nofollow noopener\" target=\"_blank\">1b<\/a>)<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 18\" title=\"Ashraf, M., Chapiro, A. &amp; Mantiuk, R. K. Resolution limit of the eye: how many pixels can we see? Print at &#010;                  https:\/\/doi.org\/10.48550\/arXiv.2410.06068&#010;                  &#010;                 (2024).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR18\" id=\"ref-link-section-d284866755e665\" rel=\"nofollow noopener\" target=\"_blank\">18<\/a>. As illustrated in Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#Fig1\" rel=\"nofollow noopener\" target=\"_blank\">1c<\/a>, this trend aligns with the structural characteristics of the types of reflective displays, e.g., electrophoretic display<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" title=\"Inoue, S. et al. High-resolution microencapsulated electrophoretic display (EPD) driven by poly-Si TFTs with four-level grayscale. IEEE Trans. Electron Devices 49, 1532&#x2013;1539 (2002).\" href=\"#ref-CR19\" id=\"ref-link-section-d284866755e673\">19<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" title=\"Kodaira, T. et al. A flexible 2.1-in. active-matrix electrophoretic display with high resolution and a thickness of 100 &#x3BC;m. J. Soc. Inf. Disp. 16, 107&#x2013;111 (2008).\" href=\"#ref-CR20\" id=\"ref-link-section-d284866755e673_1\">20<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" title=\"Liang, R. C. et al. Electrophoretic display and novel process for its manufacture. US Patent 6,750,844 (2004).\" href=\"#ref-CR21\" id=\"ref-link-section-d284866755e673_2\">21<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 22\" title=\"Comiskey, B. et al. An electrophoretic ink for all-printed reflective electronic displays. Nature 394, 253&#x2013;255 (1998).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR22\" id=\"ref-link-section-d284866755e676\" rel=\"nofollow noopener\" target=\"_blank\">22<\/a>, electrowetting display<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" title=\"Dou, Y. Y. et al. Oil motion control by an extra pinning structure in an electro-fluidic display. Sensors 18, 1114 (2018).\" href=\"#ref-CR23\" id=\"ref-link-section-d284866755e680\">23<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" title=\"Hayes, R. A. et al. 52.1: a high brightness colour 160 PPI reflective display technology based on electrowetting. SID Symp. Dig. Tech. Pap. 35, 1412&#x2013;1415 (2004).\" href=\"#ref-CR24\" id=\"ref-link-section-d284866755e680_1\">24<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 25\" title=\"Chen, X. et al. Screen printing insulator coatings for electrofluidic display devices. Phys. Status Solidi 212, 2023&#x2013;2030 (2015).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR25\" id=\"ref-link-section-d284866755e683\" rel=\"nofollow noopener\" target=\"_blank\">25<\/a>, micro-electro-mechanical system (MEMS)<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" title=\"Lim, K. S. et al. P-67: wide bandwidth reflective microshutter blind panel for transparent organic light-emitting diode display. SID Symp. Dig. Tech. Pap. 47, 1389&#x2013;1391 (2016).\" href=\"#ref-CR26\" id=\"ref-link-section-d284866755e687\">26<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" title=\"Chan, E. K. et al. Continuous color reflective display fabricated in integrated MEMS-and-TFT-on-glass process. J. Microelectromech. Syst. 26, 143&#x2013;157 (2017).\" href=\"#ref-CR27\" id=\"ref-link-section-d284866755e687_1\">27<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" title=\"Douglass, M. R. Lifetime estimates and unique failure mechanisms of the Digital Micromirror Device (DMD). In 1998 IEEE Int. Reliab. Phys. Symp. Proc. 9&#x2013;16 (IEEE, 1998).\" href=\"#ref-CR28\" id=\"ref-link-section-d284866755e687_2\">28<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 29\" title=\"Hong, J. et al. 54.4L: Late-news paper: single mirror interferometric display&#x2013;a new paradigm for reflective display technologies. SID Symp. Dig. Tech. Pap. 45, 793&#x2013;796 (2014).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR29\" id=\"ref-link-section-d284866755e690\" rel=\"nofollow noopener\" target=\"_blank\">29<\/a>, liquid crystal (LC) display<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" title=\"Sun, Z. B. et al. 49.5: True glass-based micro-display with 3&#xB5;m pixel size using deformed helix ferroelectric liquid crystal for VR\/AR displays. SID Symp. Dig. Tech. Pap. 52, 600&#x2013;603 (2021).\" href=\"#ref-CR30\" id=\"ref-link-section-d284866755e694\">30<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" title=\"Sun, Z. B. Fast ultra-high-ppi display for AR\/VR and phase modulation device based on deformed helix ferroelectric liquid crystal. PhD thesis, Hong Kong Univ. Sci. Technol. (2022).\" href=\"#ref-CR31\" id=\"ref-link-section-d284866755e694_1\">31<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" title=\"Sun, Z. B. et al. Fringe field effect free high-resolution display and photonic devices using deformed helix ferroelectric liquid crystal. Liq. Cryst. 48, 100&#x2013;110 (2021).\" href=\"#ref-CR32\" id=\"ref-link-section-d284866755e694_2\">32<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 33\" title=\"Zhang, Q. R. et al. Novel frame buffer pixel circuits and silicon backplane development for polarization-independent LCOS. IEEE Photonics J. 16, 2201109 (2024).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR33\" id=\"ref-link-section-d284866755e697\" rel=\"nofollow noopener\" target=\"_blank\">33<\/a>, where the minimum feasible pixel size typically inversely correlates with the required thickness of the device, considering issues like optical leakage and misalign issues (Supplementary Information Fig. S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">1<\/a>). Moreover, as the baseline PPD increases, the PPI required for a distance (d) tends to increase proportionally, suggesting that the closer the display is to the eye, the exponentially greater the required PPI becomes. In this context, the ability of the r-GT resonator to achieve high PPI dimensions (16,900 PPI), particularly as it has been implemented without structural or optical degradation, is notable.<\/p>\n<p>Fig. 1: Reconfigurable Gires-Tournois monopixel array.<a class=\"c-article-section__figure-link\" data-test=\"img-link\" data-track=\"click\" data-track-label=\"image\" data-track-action=\"view figure\" href=\"https:\/\/www.nature.com\/articles\/s41377-026-02228-2\/figures\/1\" rel=\"nofollow noopener\" target=\"_blank\"><img decoding=\"async\" aria-describedby=\"Fig1\" src=\"https:\/\/www.newsbeep.com\/au\/wp-content\/uploads\/2026\/03\/41377_2026_2228_Fig1_HTML.png\" alt=\"figure 1\" loading=\"lazy\" width=\"685\" height=\"620\"\/><\/a><\/p>\n<p>a Schematic of the reconfigurable Gires-Tournois (r-GT) monopixel array and the reflective light showing full-colour chromaticity. b The relationship of pixels per degree (PPD) corresponds to the distance from the eyes (d), which determines the minimum pixel pitches (P). For example, pixel density ranges required for devices from electronic billboards to VR\/AR glasses vary from 87 pixels per inch (PPI) to 10,000 PPI, respectively. c Comparison of pixel thickness and its PPI of the electrically addressable pixel array and\/or display. The right-side axis represents the distance from the eyes, and the red solid lines indicate the corresponding PPD, ranging from 100 to 102 at each PPI level (See Fig. S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">1<\/a> (Supplementary Information) for details). d Schematic of the layered structure of r-GT cell consisting of a trilayer resonator (Au\/Pr-Ge\/PANI). The optical state of PANI determines the resonance mode of r-GT. e The molecular configuration of PANI and its electrically switchable optical state, alternating between insulating (PANI0), intermediate state (PANI1+), and metallic states (PANI2+). f Simulated reflectance of various resonator configurations (Asymmetric F.-P. cavity, Trilayer GT resonator, and Tailored trilayer GT resonator). The scattered dots indicate the complex refractive indices (n) and extinction coefficient (k) of PANI under different redox states. g Reflectivity of r-GT in various configurations: \u2170) asymmetric F.-P. resonator, where PANI is applied directly to an Au substrate; \u2171) trilayer GT resonator, which includes a dense amorphous Ge layer between Au and PANI; \u2172) tailored trilayer GT resonator, consisting of a porous Ge layer between Au and PANI. Reflectivity changes as PANI cycles through different redox states from PANI0 to PANI2+ under resonant wavelength. h Absorptivity of r-GT corresponding to the change of redox state of PANI. The red curves represent the absorptivity spectra in the fully reduced state of PANI, while the blue curves correspond to the fully oxidized state. i Photo images of the colour variation of r-GT. Scale bar is 1.5\u2009cm (more experimental results in movie S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM2\" rel=\"nofollow noopener\" target=\"_blank\">1<\/a> (Supplementary Information))<\/p>\n<p>The outstanding abilities, including downscaling ability and vibrant colouration of the r-GT resonator, originate from three major points: (i) the ultrathin scale of the r-GT, (ii) the strong coupling between the conductive polymer and the GT resonator, and (iii) the sensitive shift in the resonance wavelength. The r-GT resonator developed in this study consists of a trilayer ITO\/PANI\/Pr-Ge\/Au architecture, where the engineered Pr-Ge lossy layer enables near-ideal impedance matching and supports a sharp resonance that responds sensitively to the redox-induced optical changes of PANI (Supplementary Information Fig. S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">2<\/a>). The GT resonator, which has been recently studied as a flat metasurface for generating strong resonance by controlling the speed of light, is utilized as a core photonic structure to integrate active material (PANI) strongly, resulting in a sensitive adjusting ability of resonances from single to dual mode (Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#Fig1\" rel=\"nofollow noopener\" target=\"_blank\">1d<\/a>)<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 34\" title=\"Yoo, Y. J. et al. Gires&#x2013;tournois immunoassay platform for label-free bright-field imaging and facile quantification of bioparticles. Adv. Mater. 34, 2110003 (2022).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR34\" id=\"ref-link-section-d284866755e830\" rel=\"nofollow noopener\" target=\"_blank\">34<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 35\" title=\"Park, J., Kim, S. J. &amp; Brongersma, M. L. Condition for unity absorption in an ultrathin and highly lossy film in a Gires&#x2013;Tournois interferometer configuration. Opt. Lett. 40, 1960&#x2013;1963 (2015).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR35\" id=\"ref-link-section-d284866755e833\" rel=\"nofollow noopener\" target=\"_blank\">35<\/a>. During voltage sweeps in cyclic voltammetry, PANI undergoes two reduction\/oxidation steps, displaying three redox states: PANI0 at \u22120.2\u2009V, PANI1+ at 0.4\u2009V, and PANI2+ at 0.8\u2009V, including continuous complex refractive index variation (Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#Fig1\" rel=\"nofollow noopener\" target=\"_blank\">1e<\/a>). PANI\u2019s significant refractive index change (\u2206n\u2009~\u20090.3, \u2206k\u2009~\u20090.6) during these transitions addresses the limitations of standalone conductive polymers, which do not provide sufficient light-matter interaction for effective full-colour switching across a broad hue range (Supplementary Information Fig. S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">3<\/a>). Thus, the GT resonator, integrated with PANI, is engineered to enable sensitive resonance shifts for enhanced colour purity in the additive colour regime, and to produce a precise and strong resonance with requiring only a 90\u2009nm thickness of PANI, achieving extremely low power consumption (&lt;90\u2009\u03bcW\u2009cm\u22122, Supplementary Information Figs. S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">4<\/a> and S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">5<\/a>)<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 36\" title=\"Fern&#xE1;ndez, M. R., Casanova, E. Z. &amp; Alonso, I. G. Review of display technologies focusing on power consumption. Sustainability 7, 10854&#x2013;10875 (2015).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR36\" id=\"ref-link-section-d284866755e864\" rel=\"nofollow noopener\" target=\"_blank\">36<\/a>. For example, as illustrated in Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#Fig1\" rel=\"nofollow noopener\" target=\"_blank\">1f<\/a>, various GT resonator configurations are compared to a conventional Fabry\u2013Perot cavity. The conventional GT resonator exhibits a single resonance in the visible spectrum with limited sensitivity to absorptivity modulation, as shown in the bottom contour plot and Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#Fig1\" rel=\"nofollow noopener\" target=\"_blank\">1g<\/a>. In contrast, the trilayered GT resonator, which incorporates a lossy interlayer to better match the optical impedance between interfaces, demonstrates enhanced resonance intensity and supports dual resonances within the visible range. However, its resonance peaks are relatively broad, limiting its ability to achieve high colour purity. On the other hand, the tailored trilayered GT resonator incorporating a porous Ge layer exhibits nearly perfect impedance matching, leading to near-unity absorption. This configuration enables strong resonance tuning in response to the redox activity of PANI, resulting in significantly higher colour purity due to the formation of narrow and well-defined spectral peaks (Supplementary Information Figs. S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">6<\/a>\u2013<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">8<\/a>). Furthermore, Numerical simulations confirmed that the device maintains consistent colour performance over a broad range of incident angles, corresponding to an effective field of view (FOV) of ~60\u00b0 (\u221230\u00b0 to 30\u00b0), demonstrating its potential applicability to commercial reflective displays, such as Magic Leap, which features an FOV of ~50\u00b0 (Supplementary Information Fig. S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">9<\/a>)<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 37\" title=\"Kress, B. C. Digital optical elements and technologies (EDO19): applications to AR\/VR\/MR. Proc. SPIE 11062, 1106222 (2019).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR37\" id=\"ref-link-section-d284866755e884\" rel=\"nofollow noopener\" target=\"_blank\">37<\/a>.<\/p>\n<p>By adjusting the redox states of PANI, one can finely tune the resonance conditions in the r-GT, achieving extensive hue modulation (Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#Fig1\" rel=\"nofollow noopener\" target=\"_blank\">1h<\/a> and Supplementary Information Fig. S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">10<\/a>). Figure <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#Fig1\" rel=\"nofollow noopener\" target=\"_blank\">1i<\/a> highlights its colour dynamics corresponding to the voltage range even below 1\u2009V (Movie S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM2\" rel=\"nofollow noopener\" target=\"_blank\">1<\/a>, Supplementary Information Figs. S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">11<\/a> and S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">12<\/a>). Figures S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">13<\/a> and S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">14<\/a> (Supplementary Information) show a tendency of a gradually adjusted resonance mode corresponding to the modulation in PANI\u2019s state. Considering that a newspaper typically exhibits a reflectance contrast of ~40%, our device demonstrates practical performance with ~40% reflectance in the OFF state and ~80% in the ON state<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 38\" title=\"Jin, M. L. et al. Optofluid-based reflective displays. Micromachines 9, 159 (2018).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR38\" id=\"ref-link-section-d284866755e919\" rel=\"nofollow noopener\" target=\"_blank\">38<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 39\" title=\"Nelson, E. W. et al. Full-color reflective displays. In IS&amp;T&#x2019;s 50th Annual Conference 669&#x2013;673 (The Society for Imaging Science and Technology, 1997).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR39\" id=\"ref-link-section-d284866755e922\" rel=\"nofollow noopener\" target=\"_blank\">39<\/a>. The detailed design process will be discussed in the next section.<\/p>\n<p>Building on these capabilities, the r-GT resonator stands out by achieving significant chromatic variation of 220.6\u00b0 at sub-1-volt levels. It exceeds the complementary colour range, which is essential for enhancing the perception of depth and realism in digital art and displays<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 40\" title=\"Pridmore, R. W. Complementary colors: a literature review. Color Res. Appl. 46, 482&#x2013;488 (2021).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR40\" id=\"ref-link-section-d284866755e932\" rel=\"nofollow noopener\" target=\"_blank\">40<\/a>. This performance is notable compared to previous technologies, including active photonics integrated with redox-based tunable materials (e.g., conductive polymer), phase change\/transition materials, reconfigurable photonics via dimension tuning (e.g., electrically responsive photonic crystals), and electrostatic inkjet control (e.g., electrophoretic displays), highlighting its advanced capability in precise colour modulation across a wide spectrum with dimensional downscaling into micrometer-scale (Supplementary Information Tables <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">S1<\/a> and <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">S2<\/a>) Furthermore, the thin-film r-GT resonator exhibits a wide colour modulation efficiency per unit power compared to nanostructured photonic structures such as metasurfaces and nanocaves (Supplementary Information Fig. S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">15<\/a>, Tables <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">S3<\/a> and <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">S4<\/a>)<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 8\" title=\"Hosseini, P., Wright, C. D. &amp; Bhaskaran, H. An optoelectronic framework enabled by low-dimensional phase-change films. Nature 511, 206&#x2013;211 (2014).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR8\" id=\"ref-link-section-d284866755e955\" rel=\"nofollow noopener\" target=\"_blank\">8<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 9\" title=\"Yoo, S. et al. Multicolor changeable optical coating by adopting multiple layers of ultrathin phase change material film. ACS Photonics 3, 1265&#x2013;1270 (2016).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR9\" id=\"ref-link-section-d284866755e958\" rel=\"nofollow noopener\" target=\"_blank\">9<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 41\" title=\"Zhang, S. Y. et al. Solution-processable multicolor TiO2\/polyaniline nanocomposite for integrated bifunctional electrochromic energy storage device. Appl. Surf. Sci. 607, 155015 (2023).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR41\" id=\"ref-link-section-d284866755e961\" rel=\"nofollow noopener\" target=\"_blank\">41<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 42\" title=\"Gugole, M. et al. Electrochromic inorganic nanostructures with high chromaticity and superior brightness. Nano Lett. 21, 4343&#x2013;4350 (2021).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR42\" id=\"ref-link-section-d284866755e964\" rel=\"nofollow noopener\" target=\"_blank\">42<\/a>.<\/p>\n<p>Full-colour expression of r-GT<\/p>\n<p>This section delves into the vibrant colour modulation abilities and the universality facilitated by diverse structural combinations within the r-GT. The pronounced chromaticity changes in the r-GT are attributable to sensitive adjustments in resonance conditions, driven by each layer\u2019s precise engineering based on transmission line theory, allowing exact monitoring of the interactions between light and the layered structures. Notably, the introduction of a porous (Pr)-Ge structure in the lossy material medium enhances the responsiveness of the modulation environment to changes in PANI\u2019s complex refractive index (Supplementary Information Note <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">1<\/a>; Figs. S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">16<\/a> and S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">17<\/a>). As a result, the r-GT\u2019s reflectance shows a marked negative group delay, effectively preventing chromaticity cancellation in the absorptive state (Supplementary Information Note <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">2<\/a>; Fig. S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">18<\/a>). This mechanism contributes to strong and consistent colour modulation. Figure <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#Fig2\" rel=\"nofollow noopener\" target=\"_blank\">2a, b<\/a> display chromaticity covering as thickness of PANI and redox state transitions through from PANI0 to PANI2+, illustrating 48.1% of sRGB coverage during these transitions (Supplementary Information Figs. S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">19<\/a> and S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">20<\/a>). The colour palette visually represents the range of colour modulation achievable within a single structure, highlighting the importance of active material thickness and selecting an optimal thickness (Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#Fig2\" rel=\"nofollow noopener\" target=\"_blank\">2c<\/a>). Moreover, various material combinations have been utilized to enhance colour expression, achieving performance that spans the sRGB colour space. Each colour dot in the figure represents a configuration involving different combinations of lossy materials within the r-GT, highlighted by the white triangular line that marks the sRGB range (Supplementary Information Fig. S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">21<\/a>). Figure <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#Fig2\" rel=\"nofollow noopener\" target=\"_blank\">2d, e<\/a> quantify the sRGB colour gamut coverage of the r-GT across PANI\u2019s various states, noting that the full sweep of redox states covers 69.9% of sRGB, enabling vibrant colour expression. Finally, Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#Fig2\" rel=\"nofollow noopener\" target=\"_blank\">2f<\/a> visually presents the colour palette for each configuration, demonstrating the substantial variation and impact of these material integrations, including the primary RGB colours.<\/p>\n<p>Fig. 2: Full-colour operation of r-GT.<a class=\"c-article-section__figure-link\" data-test=\"img-link\" data-track=\"click\" data-track-label=\"image\" data-track-action=\"view figure\" href=\"https:\/\/www.nature.com\/articles\/s41377-026-02228-2\/figures\/2\" rel=\"nofollow noopener\" target=\"_blank\"><img decoding=\"async\" aria-describedby=\"Fig2\" src=\"https:\/\/www.newsbeep.com\/au\/wp-content\/uploads\/2026\/03\/41377_2026_2228_Fig2_HTML.png\" alt=\"figure 2\" loading=\"lazy\" width=\"685\" height=\"653\"\/><\/a><\/p>\n<p>a CIE plot of the r-GT with lossy layer (Pr-Ge). The white triangle represents the standard RGB (sRGB) colour space, and the dashed line shows the voltage-dependent shift of the colour coordinates from \u22120.2\u2009V to 0.8\u2009V. b sRGB colour gamut coverage of r-GT across different states of PANI. c Colour palette associated with each configuration. d CIE chromaticity plots for various configurations of the r-GT with different material combinations. e, f sRGB colour gamut coverage (e) and associated colour palettes (f) of r-GT devices tailored to represent primary red, green, and blue (R, G, B) colour via PANI redox modulation<\/p>\n<p>Self-passivation layer with enhanced stability and fast response time<\/p>\n<p>Protons are essential for doping PANI, enabling fast diffusion and enhanced modulation speed; however, they also create an acidic environment, which may result in structural corrosion<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 43\" title=\"Sato, N. &amp; Okamoto, G. Electrochemical passivation of metals. In Electrochemical Materials Science (eds. Bockris, J. O. M. et al.) 193&#x2013;245 (Springer, 1981).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR43\" id=\"ref-link-section-d284866755e1106\" rel=\"nofollow noopener\" target=\"_blank\">43<\/a>. To protect against the corrosion issue, Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#Fig3\" rel=\"nofollow noopener\" target=\"_blank\">3a<\/a> illustrates the irreversible, intentionally applied oxidation of the Ge layer during the first cycle of voltage sweeps in cyclic voltammetry. The oxygen ions and electrons involved in oxidation are derived from the electrolyte and the conductive substrate, resulting in the formation of the GeO2 layer through processes (i) and (ii)<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 44\" title=\"Ehman, M. F. et al. Characterisation of thin surface films on germanium in various solvents by ellipsometry. J. Mater. Sci. 6, 969&#x2013;973 (1971).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR44\" id=\"ref-link-section-d284866755e1115\" rel=\"nofollow noopener\" target=\"_blank\">44<\/a>. As shown in Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#Fig3\" rel=\"nofollow noopener\" target=\"_blank\">3b<\/a>, the electrochemical reactions of the r-GT monopixel are examined during 100 cycles. The cyclic voltammetry curves show a high current peak intensity at a specific voltage during the first cycle, followed by stable redox reactions in the subsequent cycles (Supplementary Information Fig. S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">22<\/a>). This phenomenon suggests that partial oxidation of Ge occurs, leading to the formation of the self-passivation layer (SPL) to protect its porous structure from acidic electrolyte<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 45\" title=\"Almuslem, A. S. et al. Water soluble nano-scale transient material germanium oxide for zero toxic waste based environmentally benign nano-manufacturing. Appl. Phys. Lett. 110, 074103 (2017).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR45\" id=\"ref-link-section-d284866755e1129\" rel=\"nofollow noopener\" target=\"_blank\">45<\/a>. During the first cycle of the cyclic voltammetry reaction, the peak current density of the r-GT resonator at 0.45\u2009V points to the oxidation of Ge to GeO2, in response to oxygen sources being absorbed during the deposition process and\/or hydroxyl groups diffusing from the electrolyte<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 46\" title=\"Arro, C. R., Mohamed, A. T. I. &amp; Bensalah, N. Impact of Ge content on the electrochemical performance of Germanium Oxide\/Germanium\/ reduced graphene (GeO2\/Ge\/r-GO) hybrid composite anodes for lithium-ion batteries. Mater. Today Commun. 30, 103151 (2022).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR46\" id=\"ref-link-section-d284866755e1138\" rel=\"nofollow noopener\" target=\"_blank\">46<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 47\" title=\"Bioud, Y. A. et al. Shape control of cathodized germanium oxide nanoparticles. Electrochem. Commun. 122, 106906 (2021).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR47\" id=\"ref-link-section-d284866755e1141\" rel=\"nofollow noopener\" target=\"_blank\">47<\/a>. To confirm the necessity of the intentionally formed SPL through Ge oxidation, the device is fabricated using the conventional material (SiO2) for comparison. Under acidic conditions, the Ge medium is fully oxidized, resulting in degraded electrochromic properties. On the other hand, SPL-based r-GT provides great protection ability, showing great reversibly switchable ability, enabled by GeO2 passivation with inherently lower interface defect density than SiO2 passivation<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" title=\"Mirmohseni, A. &amp; Oladegaragoze, A. Anti-corrosive properties of polyaniline coating on iron. Synth. Met. 114, 105&#x2013;108 (2000).\" href=\"#ref-CR48\" id=\"ref-link-section-d284866755e1155\">48<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" title=\"Kang, J. et al. Suppression of dark current in GeOx-passivated germanium metal-semiconductor-metal photodetector by plasma post-oxidation. Opt. Express 23, 16967&#x2013;16976 (2015).\" href=\"#ref-CR49\" id=\"ref-link-section-d284866755e1155_1\">49<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 50\" title=\"Saito, S. et al. First-principles study to obtain evidence of low interface defect density at Ge\/GeO2 interfaces. Appl. Phys. Lett. 95, 011908 (2009).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR50\" id=\"ref-link-section-d284866755e1158\" rel=\"nofollow noopener\" target=\"_blank\">50<\/a>. (Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#Fig3\" rel=\"nofollow noopener\" target=\"_blank\">3c<\/a>). As proof of our suggestion, energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) were conducted, revealing a corresponding increase in the GeO2 proportion in the XPS O 1\u2009s signal (Supplementary Information Fig. S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">23<\/a>). In addition, the Ge 3\u2009d photoelectron spectrum before (blue line) and after redox reaction (red line) show a change in spectral intensity with a shift from the initial state to a higher binding energy corresponding to the GeO2 peak profile (Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#Fig3\" rel=\"nofollow noopener\" target=\"_blank\">3d<\/a>). As shown in Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#Fig3\" rel=\"nofollow noopener\" target=\"_blank\">3e<\/a>, comparison of the CV curves for Au\/Pr-Ge\/ITO, Pr-Ge\/PANI\/ITO, and the r-GT resonator reveals redox peaks in the PANI-containing structure relative to structure without PANI. In addition, the structure containing Au effectively suppresses excessive oxidation of Pr-Ge, enabling the formation of SPL. These results closely match the EDS mapping profile in terms of oxygen and nitrogen atomic proportion. Figure S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">24<\/a> (Supplementary Information) also presents EDS results showing an increase in nitrogen content, which occurred simultaneously with the doping\/de-doping process. Figure <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#Fig3\" rel=\"nofollow noopener\" target=\"_blank\">3f<\/a> shows that the reflectance spectrum repeatedly activates and reverts to its initial state and different voltages (\u22120.2\u2009V and 0.6\u2009V, interval is 10\u2009s) during 700 cycles (Supplementary Information Figs. S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">25<\/a> and S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">26<\/a>). Figure <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#Fig3\" rel=\"nofollow noopener\" target=\"_blank\">3g<\/a> shows that proton has the smallest cation radius and largest diffusion coefficient in comparison with other cations, resulting in a fast response time of doped in just 34\u2009ms (oxidation) and effectively de-doped to the reduced state within 171\u2009ms (reduction) (Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#Fig3\" rel=\"nofollow noopener\" target=\"_blank\">3h<\/a>; Supplementary Information Figs. S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">27<\/a> and S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">28<\/a>). The r-GT resonator is measured into the other electrolyte containing either sodium ion (Na+) or potassium ion (K+), which have larger ionic radii and lower diffusion coefficients compared to protons. Figure <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#Fig3\" rel=\"nofollow noopener\" target=\"_blank\">3i<\/a> displays a radar chart showing that both Na+ and K\u207a-based electrolytes exhibit overall lower performance in terms of modulated hue range (H), response time (T), and reversibility (R). Building on the results, it suggests that proton-based electrochemical reactions guarantee sufficient redox responses with fast reaction speeds. Although they may be limited by corrosive properties, we have overcome this issue using SPL, thereby expanding the range of applicability for PANI-based photonics (Supplementary Information Table <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">S5<\/a>; Figs. S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">29<\/a> and S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">30<\/a>).<\/p>\n<p>Fig. 3: Characterization of the self-passivation layer (SPL) of r-GT.<a class=\"c-article-section__figure-link\" data-test=\"img-link\" data-track=\"click\" data-track-label=\"image\" data-track-action=\"view figure\" href=\"https:\/\/www.nature.com\/articles\/s41377-026-02228-2\/figures\/3\" rel=\"nofollow noopener\" target=\"_blank\"><img decoding=\"async\" aria-describedby=\"Fig3\" src=\"https:\/\/www.newsbeep.com\/au\/wp-content\/uploads\/2026\/03\/41377_2026_2228_Fig3_HTML.png\" alt=\"figure 3\" loading=\"lazy\" width=\"685\" height=\"605\"\/><\/a><\/p>\n<p>a Illustration of the formation of SPL. The porous Ge layer undergoes oxidation through electrons and oxygen. b Cyclic voltammetry (CV) curve of the r-GT at first cycle (red line) and after 30 cycles (blue line) with a reference electrode (RE, Ag\/AgCl). A strong oxidation peak occurs during the initial oxidation stage, followed by a stable electrochemical response in subsequent cycles. c Schematic of the permeability of photons through the SPL and SiO2 layer, along with corresponding photo images of the reflective colours. d XPS spectra of O 1\u2009s and Ge 3\u2009d at the interface between PANI and porous Ge layer. The blue line represents the state of the r-GT before the redox reaction, while the red line shows the state after the reaction. e CV curve of Au\/Pr-Ge\/ITO (blue line), Pr-Ge\/PANI\/ITO (green line), and r-GT resonator (red line) at a scan rate of 0.05\u2009V\u2009s\u22121. Energy dispersive spectroscopy (EDS) analysis of a cross-sectional r-GT. The EDS mapping reveals that the atomic percentage of oxygen (blue) is increased in the SPL region after the redox reaction. f Reflectance spectrum with potential cycled from \u22120.2\u2009V to 0.6\u2009V (interval: 10\u2009s) over 700 cycles. g Comparison of various cations with photon based on cation radius and diffusion coefficient. h The electrically responsive reflectance exhibits a switching speed with a rise time of 34\u2009ms and a fall time of 171\u2009ms, respectively. i Comparison of different cation-based electrolytes in terms of hue range (H), response time (T), and reversibility (R)<\/p>\n<p>Flexibility in scaling the dimensions of the r-GT resonator<\/p>\n<p>The optical\/chemical robustness of r-GT offers the flexibility in scaling the pixel dimension from centimeter-scale to micrometer-scale. Particularly, in this section, we demonstrate the diverse scale of the reconfigurable pixel array with a colour switching function. Figure <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#Fig4\" rel=\"nofollow noopener\" target=\"_blank\">4a<\/a> shows the Bayer-pattern with 16-unit dots, incorporating the painting Girl with a Pearl Earring (Johannes Vermeer), achieving a compact panel size smaller than a 1-dime coin. By varying the density of unit dots, the spatial fill factor can be adjusted to represent 16 graded intensity levels (4-bit) in the corresponding pixel array (Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#Fig4\" rel=\"nofollow noopener\" target=\"_blank\">4b<\/a>; Supplementary Information Fig. S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">31a\u2013d<\/a>). The 5\u2009\u00b5m square pattern is defined as a unit pixel, and the array patterns display a clear high-density (HD) image (Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#Fig4\" rel=\"nofollow noopener\" target=\"_blank\">4c<\/a>; Supplementary Information Fig. S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">32<\/a>). The chromaticity of the HD patterned r-GT resonator can be adjusted from yellow to blue under sub-1-volt conditions (Supplementary Information Fig. S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">31e<\/a>). Quantitatively, the pixel size can be classified according to target applications by considering the distance between the display and the observer\u2019s eyes. In this regard, we experimentally confirmed diverse sizes of pixels with the colour switching functionality. Figure <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#Fig4\" rel=\"nofollow noopener\" target=\"_blank\">4<\/a>d, e illustrates the pixel size distribution ranging from the few micrometer-scale required for VR\/AR displays to the centimeter-scale needed for electronic billboards<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 51\" title=\"Chang, C. L. et al. Toward the next-generation VR\/AR optics: a review of holographic near-eye displays from a human-centric perspective. Optica 7, 1563&#x2013;1578 (2020).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR51\" id=\"ref-link-section-d284866755e1337\" rel=\"nofollow noopener\" target=\"_blank\">51<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 52\" title=\"Aston, M. Design of large-area OLED displays utilizing seamless tiled components. J. Soc. Inf. Disp. 15, 535&#x2013;540 (2007).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR52\" id=\"ref-link-section-d284866755e1340\" rel=\"nofollow noopener\" target=\"_blank\">52<\/a>. The active area of r-GT is successfully patterned with different pixel sizes: i) P\u2009=\u2009160\u2009\u00b5m; ii) P\u2009=\u2009370\u2009\u00b5m; iii) P\u2009=\u2009630\u2009\u00b5m; iv) P\u2009=\u20091300\u2009\u00b5m; and v) centimeter-scale image printing. Additionally, the experimental validation of scaling down has been confirmed up to a pixel pitch of 1.5\u2009\u00b5m, achieving 16,900 PPI (Supplementary Information Figs. S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">33<\/a> and S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">34<\/a>). Diverse sizes of each pixel are compared with previously reported reflective-type displays with pixel operation based on reconfigurable photonics using various types of active materials, such as electrochemical doping material (PANI<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" title=\"Park, H. et al. A skin-integrated transparent and stretchable strain sensor with interactive color-changing electrochromic displays. Nanoscale 9, 7631&#x2013;7640 (2017).\" href=\"#ref-CR53\" id=\"ref-link-section-d284866755e1367\">53<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" title=\"Liu, G. D. et al. Employing polyaniline\/viologen complementarity to enhance coloration and charge dissipation in multicolor electrochromic display with wide modulation range. J. Colloid Interface Sci. 655, 493&#x2013;507 (2024).\" href=\"#ref-CR54\" id=\"ref-link-section-d284866755e1367_1\">54<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 55\" title=\"Gong, H. et al. Ultrathin flexible electrochromic devices enabled by highly transparent ion-conducting films. J. Mater. Chem. A 11, 8939&#x2013;8949 (2023).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR55\" id=\"ref-link-section-d284866755e1370\" rel=\"nofollow noopener\" target=\"_blank\">55<\/a>, PEODT:PSS<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 56\" title=\"Brooke, R. et al. Electrochromic displays manufactured by a combination of vapor phase polymerization and screen printing. Adv. Mater. Technol. 7, 2200054 (2022).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR56\" id=\"ref-link-section-d284866755e1374\" rel=\"nofollow noopener\" target=\"_blank\">56<\/a>, WO3<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 57\" title=\"Li, Y. W. et al. Colorful electrochromic displays with high visual quality based on porous metamaterials. Adv. Mater. 35, 2300116 (2023).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR57\" id=\"ref-link-section-d284866755e1379\" rel=\"nofollow noopener\" target=\"_blank\">57<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 58\" title=\"Zhang, W., Li, H. Z. &amp; Elezzabi, A. Y. Electrochromic displays having two-dimensional CIE color space tunability. Adv. Funct. Mater. 32, 2108341 (2022).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR58\" id=\"ref-link-section-d284866755e1382\" rel=\"nofollow noopener\" target=\"_blank\">58<\/a>), phase-change materials (GST<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 8\" title=\"Hosseini, P., Wright, C. D. &amp; Bhaskaran, H. An optoelectronic framework enabled by low-dimensional phase-change films. Nature 511, 206&#x2013;211 (2014).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR8\" id=\"ref-link-section-d284866755e1386\" rel=\"nofollow noopener\" target=\"_blank\">8<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 9\" title=\"Yoo, S. et al. Multicolor changeable optical coating by adopting multiple layers of ultrathin phase change material film. ACS Photonics 3, 1265&#x2013;1270 (2016).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR9\" id=\"ref-link-section-d284866755e1389\" rel=\"nofollow noopener\" target=\"_blank\">9<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 59\" title=\"Prabhathan, P. et al. Electrically tunable steganographic nano-optical coatings. Nano Lett. 23, 5236&#x2013;5241 (2023).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR59\" id=\"ref-link-section-d284866755e1392\" rel=\"nofollow noopener\" target=\"_blank\">59<\/a>, VO2<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 60\" title=\"Guo, T. B. et al. Durable and programmable ultrafast nanophotonic matrix of spectral pixels. Nat. Nanotechnol. 19, 1635&#x2013;1643 (2024).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR60\" id=\"ref-link-section-d284866755e1398\" rel=\"nofollow noopener\" target=\"_blank\">60<\/a>), liquid crystal (LC)<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 61\" title=\"Franklin, D. et al. Polarization-independent actively tunable colour generation on imprinted plasmonic surfaces. Nat. Commun. 6, 7337 (2015).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR61\" id=\"ref-link-section-d284866755e1402\" rel=\"nofollow noopener\" target=\"_blank\">61<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 62\" title=\"Huang, M. T. et al. Dynamically tunable structural colors enabled by pixelated programming of soft materials on thickness. Adv. Opt. Mater. 11, 2300573 (2023).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR62\" id=\"ref-link-section-d284866755e1405\" rel=\"nofollow noopener\" target=\"_blank\">62<\/a>, dielectric (SiO2) nanoparticles-based photonic crystal<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 63\" title=\"Fu, Q. Q. et al. Electrically responsive photonic crystals with bistable states for low-power electrophoretic color displays. Nat. Commun. 13, 7007 (2022).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR63\" id=\"ref-link-section-d284866755e1411\" rel=\"nofollow noopener\" target=\"_blank\">63<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 64\" title=\"Fu, Q. Q., Zhu, H. M. &amp; Ge, J. P. Electrically tunable liquid photonic crystals with large dielectric contrast and highly saturated structural colors. Adv. Funct. Mater. 28, 1804628 (2018).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR64\" id=\"ref-link-section-d284866755e1414\" rel=\"nofollow noopener\" target=\"_blank\">64<\/a>, and metal electrodeposition<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 65\" title=\"Meng, Z. et al. Tunable microwave absorbing devices enabled by reversible metal electrodeposition. ACS Appl. Mater. Interfaces 16, 11686&#x2013;11693 (2024).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR65\" id=\"ref-link-section-d284866755e1418\" rel=\"nofollow noopener\" target=\"_blank\">65<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 66\" title=\"Moon, C. W., Kim, Y. &amp; Hyun, J. K. Active electrochemical high-contrast gratings as on\/off switchable and color tunable pixels. Nat. Commun. 13, 3391 (2022).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR66\" id=\"ref-link-section-d284866755e1421\" rel=\"nofollow noopener\" target=\"_blank\">66<\/a> (Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#Fig4\" rel=\"nofollow noopener\" target=\"_blank\">4f<\/a>; Supplementary Information Fig. S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">35<\/a>; Table <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">S6<\/a>). As described, depending on the type of active materials, the feasible dimensions can be influenced. For example, when adjusting the period of a photonic crystal based on dielectric nanoparticles (i.e., categorized as a dimension change), there is a required vertical dimension, which may limit the adjustments in the lateral dimension. On the other hand, examples based on PCMs, which can alter colour by applying localized heat, have experimentally demonstrated very small pixelization down to ~300\u2009nm. However, in this case, the heating is applied via an atomic force microscope tip, and there is a lack of circuit-based pixel-by-pixel addressing capability. Also, from the viewpoint of colour adjusting, despite vibrant colour changes, there are no cases that achieve a sufficient complementary range (\u0394Hue &gt; 180\u00b0). This may be due to \u2170) the limitations in the change in optical constants of the active materials themselves, or \u2171) the absence of synergistic coupling with the photonic structure necessary to induce sufficient light-matter interaction. In this context, r-GT successfully demonstrates great flexibility in scaling profits for diverse types of applications and also provides an extensive colour modulation.<\/p>\n<p>Fig. 4: Electrically triggered optical response and programmable memory functions.<a class=\"c-article-section__figure-link\" data-test=\"img-link\" data-track=\"click\" data-track-label=\"image\" data-track-action=\"view figure\" href=\"https:\/\/www.nature.com\/articles\/s41377-026-02228-2\/figures\/4\" rel=\"nofollow noopener\" target=\"_blank\"><img decoding=\"async\" aria-describedby=\"Fig4\" src=\"https:\/\/www.newsbeep.com\/au\/wp-content\/uploads\/2026\/03\/41377_2026_2228_Fig4_HTML.png\" alt=\"figure 4\" loading=\"lazy\" width=\"685\" height=\"783\"\/><\/a><\/p>\n<p>a Photograph of the high-density (HD) patterned r-GT resonator alongside a 1-dime coin. b Bayer-pattern image of the painting \u201cGirl with a Pearl Earring\u201d with a 16-level scale. c Microscope image of a selected region at a voltage of HD r-GT array. The bluish image shows the r-GT in the PANI2+ state. d Recommended scale diagram of the pixel size corresponding to commercial display devices. e Optical microscopy images of each pixel showing electrically switchable dual states and the electrochromic emergency exit sign. f Comparison of optical modulation range versus span (~220.67\u00b0) of the operated pixel size with various tunable photonics systems. Scale bars, a 1\u2009cm, b 1\u2009mm, c 250\u2009\u03bcm, 15\u2009\u03bcm, and 10\u2009\u03bcm. e \u2170\u2013\u2173 300\u2009\u03bcm and \u2174 5\u2009mm<\/p>\n<p>Addressable characteristics of r-GT monopixel array<\/p>\n<p>To demonstrate the addressable r-GT array, we fabricated a 5 by 5 pixel array, each pixel measuring 9\u2009mm\u00b2. Figure <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#Fig5\" rel=\"nofollow noopener\" target=\"_blank\">5a<\/a> presents a schematic and a photographic image of the r-GT array, which includes a working electrode (WE), counter electrode (CE), and reference electrode (RE). The potential applied to the WE is transferred via an anisotropic conductive film (ACF) attached to the addressing line (Ti\/Au). The CE and RE utilize Pt and Ag\/AgCl electrodes, respectively. Figure S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">36<\/a> (Supplementary Information) details the design and mask patterns of the addressable r-GT monopixel array. Each pixel is controlled by applying pre-programmed potentials that determine the colours, i.e., \u22120.2\u2009V for yellow and 0.6\u2009V for blue. By selectively applying the target voltage, the letter pattern \u2018ACTIVE MONOPIXEL\u2019 is displayed (Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#Fig5\" rel=\"nofollow noopener\" target=\"_blank\">5b<\/a>; Supplementary Information Figs. S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">37<\/a> and S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">38<\/a>). Figure <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#Fig5\" rel=\"nofollow noopener\" target=\"_blank\">5c<\/a> shows selectively controlled patterns in diverse colours achieved by applying different potentials: 0.2\u2009V for green, 0.4\u2009V for cyan, and 0.8\u2009V for magenta. By applying a series of pre-programmed, selective potentials to pixels with varying potentials and addresses, sequential image patterns are demonstrated. Intriguingly, PANI provides a temporal memory function with a metastable ability that maintains its redox states with open-circuit memory properties for over 4\u2009hours (Supplementary Information Fig. S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">39<\/a>)<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 16\" title=\"Peng, J. L. et al. Scalable electrochromic nanopixels using plasmonics. Sci. Adv. 5, eaaw2205 (2019).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR16\" id=\"ref-link-section-d284866755e1546\" rel=\"nofollow noopener\" target=\"_blank\">16<\/a>. Leveraging this property, we showcased a Memory-in-Pixel capability<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 67\" title=\"Lee, S. H. et al. Memory-in-pixel circuit for low-power liquid crystal displays comprising oxide thin-film transistors. IEEE Electron Device Lett. 38, 1551&#x2013;1554 (2017).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR67\" id=\"ref-link-section-d284866755e1551\" rel=\"nofollow noopener\" target=\"_blank\">67<\/a>, resulting in significantly reduced power consumption for maintaining pre-patterned images. Figure <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#Fig5\" rel=\"nofollow noopener\" target=\"_blank\">5d<\/a> illustrates four series of sequences by demonstrating the game of Tetris being played. Under these conditions, the power density required for colour switching is measured at only 2.31\u2009mJ, eliminating the need for continuous encoding of colour information (Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#Fig5\" rel=\"nofollow noopener\" target=\"_blank\">5e<\/a>). To compare the power density of the r-GT resonator with that of a commercial display, we assumed the power consumption for an LED, calculated at 13.49\u2009mJ, to align with the minimum and maximum power values provided by the r-GT resonator (Fig. <a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#Fig5\" rel=\"nofollow noopener\" target=\"_blank\">5f<\/a>; Supplementary Information Fig. S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">40<\/a>).<\/p>\n<p>Fig. 5: Electrochemical characterization and colouration performance of the r-GT monopixel array.<a class=\"c-article-section__figure-link\" data-test=\"img-link\" data-track=\"click\" data-track-label=\"image\" data-track-action=\"view figure\" href=\"https:\/\/www.nature.com\/articles\/s41377-026-02228-2\/figures\/5\" rel=\"nofollow noopener\" target=\"_blank\"><img decoding=\"async\" aria-describedby=\"Fig5\" src=\"https:\/\/www.newsbeep.com\/au\/wp-content\/uploads\/2026\/03\/41377_2026_2228_Fig5_HTML.png\" alt=\"figure 5\" loading=\"lazy\" width=\"685\" height=\"901\"\/><\/a><\/p>\n<p>a Schematic illustration of the optical measurement setup for the r-GT resonator and the photo images of a 5\u2009\u00d7\u20095 r-GT resonator array. b Photograph of the individually controlled pixel array with on\/off function, which represents letters of \u201cACTIVE MONOPIXEL\u201d. c Photo images of electrically addressable pixel array with pre-programmed scenarios including moving motion and colouration. d Optical memory properties of the r-GT monopixel for sequential visualization of the famous game of Tetris tasks over time. e, f Comparison of the power consumption of the r-GT resonator (e) and that of commercial light-emitting diode (LED) during sequence processing (f)<\/p>\n<p>As a practical demonstration of reflective display, Fig. S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">41<\/a> (Supplementary Information) illustrates an energy-efficient display with excellent visibility, even in outdoor environments. The figure demonstrates how the r-GT resonator, utilizing ambient light as a light source, maintains clear visibility across various lighting conditions, with an illumination range of 5\u2013200\u2009W\u2009m\u22122. The captured pictures were converted to grayscale, and intensities were extracted from selected pixels (dashed red line in Supplementary Information Fig. S<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#MOESM1\" rel=\"nofollow noopener\" target=\"_blank\">41d<\/a>) for highlighting the contrast between letters and the background. In the case of the r-GT display, increasing ambient illumination resulted in enhanced contrast, improving visual legibility. In contrast, the LED display exhibited an insufficient contrast ratio to meet the level 5 requirement of the WCAG 2.1 guidelines for optimal visibility in web conditions, as referred to the W3C Web Content Accessibility Guidelines<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 68\" title=\"World Wide Web Consortium. Web content accessibility guidelines (WCAG) 2.1. W3C. &#010;                  https:\/\/www.w3.org\/TR\/2025\/REC-WCAG21-20250506\/&#010;                  &#010;                 (2025).\" href=\"http:\/\/www.nature.com\/articles\/s41377-026-02228-2#ref-CR68\" id=\"ref-link-section-d284866755e1652\" rel=\"nofollow noopener\" target=\"_blank\">68<\/a>. Consequently, LED displays exhibit lower visibility than this value under high illumination, even at the highest panel brightness with consuming higher power density.<\/p>\n","protected":false},"excerpt":{"rendered":"Concept of reconfigurable Gires-Tournois monopixels Reflective displays offer a compact and efficient design, leveraging external light without an&hellip;\n","protected":false},"author":2,"featured_media":512509,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[24],"tags":[64,63,53656,31794,55016,162147,30993,17479,59936,59935,51320,292,59937,128],"class_list":{"0":"post-512508","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-physics","8":"tag-au","9":"tag-australia","10":"tag-displays","11":"tag-lasers","12":"tag-microwaves","13":"tag-nanocavities","14":"tag-nanophotonics-and-plasmonics","15":"tag-optical-and-electronic-materials","16":"tag-optical-devices","17":"tag-optics","18":"tag-photonics","19":"tag-physics","20":"tag-rf-and-optical-engineering","21":"tag-science"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts\/512508","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/comments?post=512508"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts\/512508\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/media\/512509"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/media?parent=512508"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/categories?post=512508"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/tags?post=512508"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}