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KAIST Enables Ultra-High-Resolution AR·VR Without Battery Burden
<(From Left) Professor Young Min Song, Ph.D candidate Hyo Eun Jeong, (Upper Left) Professor Hyeon-Ho Jeong, Dr. Joo Hwan Ko>
A new display technology has emerged that significantly increases resolution while consuming almost no power. A Korean research team has developed a “monopixel” structure in which a single pixel can independently change colors while consuming minimal energy to maintain them. This breakthrough opens the possibility of creating sharper AR/VR displays without heavy battery demands.
KAIST (President Kwang Hyung Lee) announced on the 29th of March that a research team led by Professor Young Min Song of the School of Electrical Engineering, in collaboration with Professor Hyeon-Ho Jeong’s team at Gwangju Institute of Science and Technology (GIST, President Ki-Cheol Lim), has developed a new low-power monopixel technology called a “reconfigurable Gires–Tournois resonator (r-GT).” This system uses electrochromic materials—substances that change color when electricity is applied—to produce colors with very low power consumption.
Displays have been making pixels increasingly smaller to achieve higher resolution. However, as pixels shrink, power consumption rises and brightness decreases. This is especially challenging for AR/VR devices, which must achieve both extremely small pixels and low power consumption due to their proximity to the human eye.
The r-GT pixel developed by the research team changes color when voltage is applied, and once changed, the color is maintained for a certain period even after the power is turned off. In other words, power is only required when changing colors, while maintaining color requires almost no energy.
The core of this technology lies in two elements. First is a conductive polymer, polyaniline (PANI), whose properties change when voltage is applied. This material responds even at voltages below 1 volt (V), altering its refractive index and thereby changing color. The refractive index refers to how much light bends when passing through a material, and changes in this value lead to changes in perceived color.
Second, the system incorporates a resonator structure that reflects light multiple times to amplify specific colors. This structure enhances even small changes, enabling vivid color expression with minimal power.
As a result, the system achieved a wide color variation exceeding 220° using ultra-low power (90 μW cm⁻²). In simple terms, it can express more than half of the full color wheel (360°) using only about 0.00009 watts per square centimeter.
Another key feature is the “monopixel” structure. Unlike conventional displays that divide a single pixel into red (R), green (G), and blue (B) subpixels, the monopixel approach allows one pixel to independently produce various colors. This enables more pixels within the same area, resulting in higher resolution and reduced light loss, leading to clearer images.
Additionally, PANI retains its color state even after the applied voltage is removed. This confirms the feasibility of a “memory-in-pixel” display, where energy is used only when changing colors, not when maintaining them.
<Reflective display AI image>
The research team demonstrated that this technology can achieve a wide color range (220.6°) and reduce pixel size to as small as 1.5 micrometers (μm), corresponding to an ultra-high resolution of up to approximately 16,900 PPI—beyond the level where individual pixels can be distinguished by the human eye.
Moreover, even with a single-pixel structure, the system can represent about 48.1% of the standard sRGB color gamut, and up to 69.9% with varied material combinations, enabling richer color expression.
The team fabricated a 5×5 monopixel array to verify performance. The energy required to change colors was extremely low (2.31 mJ), demonstrating up to 5.8 times lower power consumption compared to conventional LEDs. As a reflective display, it also becomes more visible under brighter ambient lighting, since it uses external light rather than emitting its own.
<Structure and Representative Results of an Electrically Tunable Single Reflective Resonant Device Using Conductive Polymers>
This study demonstrates that combining electrochemical materials with optical resonator structures enables full-color implementation at ultra-low power. It is expected to be applied in various fields requiring energy efficiency, including ultra-high-resolution near-eye displays for AR/VR, wearable devices, outdoor displays, and electronic paper. It also suggests the potential for sustainable and energy-efficient display technologies by minimizing power consumption during color retention.
Professor Young Min Song stated, “This technology allows a wide range of color changes using very little electricity,” adding, “When combined with future display driving methods, it could enable not only clearer and more energy-efficient ultra-high-resolution displays but also a variety of optical applications.”
This research was conducted with Hyo Eun Jeong, an integrated M.S./Ph.D. student at KAIST, as co-first author, and Professor Young Min Song as the corresponding author. The results were published online on February 28 in Light: Science & Applications, a leading international journal in optics.
※ Paper title: “Sub-1-volt, reconfigurable Gires-Tournois resonators for full-coloured monopixel array,” DOI: https://www.nature.com/articles/s41377-026-02228-2
This research was supported by multiple programs funded by the Ministry of Science and ICT, the National Research Foundation of Korea (NRF), the InnoCORE-GIST program, nanomaterials and technology development initiatives, future medical innovation programs, international collaboration hubs, and the Ministry of Trade, Industry and Energy (MOTIE).
2026.03.30 View 772 -
Makes Summer Cooler and Winter Warmer Without Power
<(Front row from left)Professor Young Min Song, Ph.D candidate Hyung Rae Kim, M.S candidate Hyunkyu Kwak, (Back row from left)Ph.D candidate Hyo Eun Jeong, Dr. Sehui Chang, Ph.D candidate Do Hyeon Kim, (Circle from left) Professor Dae-Hyeong Kim, Dr. Yoonsoo Shin, Dr. Se-Yeon Heo>
The poplar (Populus alba) has a unique survival strategy: when exposed to hot and dry conditions, it curls its leaves to expose the ventral surface, reflecting sunlight, and at night, the moisture condensed on the leaf surface releases latent heat to prevent frost damage. Plants have evolved such intricate mechanisms in response to dynamic environmental fluctuations in diurnal and seasonal temperature cycles, light intensity, and humidity, but there have been few instances of realizing such a sophisticated thermal management system with artificial materials. Through this research, the KAIST research team has developed an artificial material that mimics the thermal management strategy of the poplar leaf, significantly increasing the applicability of power-free, self-regulating thermal management technology in applications such as building facades, roofs, and temporary shelters.
KAIST announced on November 18 that the research team led by Professor Young Min Song of the School of Electrical Engineering, in collaboration with Professor Dae-Hyeong Kim’s team at Seoul National University, has developed a flexible hydrogel-based ‘Latent-Radiative Thermostat (LRT)’ that mimics the natural heat regulation strategy of the poplar leaf.
The LRT developed by the research team is a bio-inspired thermal regulator that autonomously switches between cooling and heating modes. This technology is a new thermal management technique that can simultaneously realize latent heat regulation through the evaporation and condensation of water, and radiative heat regulation using light reflection and transmission, all within a single device.
The primary functional material is a composite that integrates lithium ions (Li+) and hydroxypropyl cellulose (HPC) within a polyacrylamide (PAAm) hydrogel. Li+ maintains warmth by condensing and absorbing moisture to regulate latent heat, and HPC changes between transparent and opaque states according to temperature changes, regulating the reflection and absorption of sunlight to switch between cooling and heating modes.
When the temperature rises, HPC molecules aggregate, causing the hydrogel to become opaque, which reflects sunlight and strengthens the natural cooling effect. The resulting LRT automatically switches among four thermal management modes based on the surrounding temperature, humidity, and sunlight.
<Figure 1. Schematic of a hydrogel-based self-regulating temperature controller inspired by the thermal management strategy of poplar leaves.>
▶ In night/cold environments below the dew point temperature, it maintains warmth by absorbing and condensing moisture in the air and releasing heat. ▶ On cold days with weak sunlight, it transmits sunlight and the absorbed moisture absorbs near-infrared radiation to produce a heating effect. ▶ In hot and dry conditions, internal moisture evaporates, resulting in powerful evaporative cooling. ▶ Under strong sunlight and high-temperature conditions, the HPC becomes opaque to reflect sunlight, and simultaneously, evaporative cooling operates to lower the temperature. That is, it is a bioinspired thermal management device that autonomously switches between cooling and heating modes according to the surrounding environment without requiring power.
Through this research, the LRT has demonstrated the performance to stay cooler in the summer and warmer in the winter. The research team confirmed that the thermal regulation properties can be finely tuned to various climate conditions by adjusting the concentrations of Li+ and HPC, and the durability and mechanical strength of the material were significantly improved by adding TiO2 nanoparticles. In outdoor experiments, the LRT maintained temperatures up to 3.7 °C lower in the summer and up to 3.5 °C higher in the winter compared to conventional cooling materials. Furthermore, a simulation covering 7 climate zones (ASHRAE standards) showed an annual energy saving of up to 153 MJ/m2 compared to existing roof coatings. This study is a case of the engineering implementation of the sophisticated thermal management strategies observed in nature. It is anticipated to serve as a next-generation thermal management platform for environments where power-based cooling and heating are difficult, such as building facades, roofs, and temporary shelters.
<Figure 2. Outdoor temperature measurement results and simulated energy savings.>
In a statement, Professor Young Min Song said, “This research is significant as it technically reproduced nature's intelligent thermal regulation strategy, presenting a thermal management device that self-adapts to seasonal and climate changes. It can be expanded into an intelligent thermal management platform applicable to various environments in the future.” This study was co-first authored by PhD candidate Hyung Rae Kim (School of Electrical Engineering, KAIST). Professor Young Min Song (School of Electrical Engineering, KAIST) participated as a corresponding author. The research was published online on November 4th in Advanced Materials (IF 26.8), a world-leading journal in the field of material science.
※ Paper Title: Hydrogel Thermostat Inspired by Photoprotective Foliage Using Latent and Radiative Heat Control, DOI: https://doi.org/10.1002/adma.202516537
This work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIT) (RS-2025-16063568, RS-2025-16902996, RS-2023-NR077254, RS-2022-NR068140). This work was supported by the InnoCORE program of the Ministry of Science and ICT(GIST InnoCORE KH0830). This work also was supported by the Technology Innovation Program(or Industrial Strategic Technology Development Program-Bio-industry Technology Development Project)(RS-2024-00467230, Development of a Digital Healthcare Device for Non-invasive Continuous Monitoring of Myocardial Infarction Biomarkers Based on Mid-Infrared Nano-Optical Filters) funded By the Ministry of Trade Industry & Energy(MOTIE, Korea)
2025.11.18 View 2287