Domestic researchers have succeeded in developing a phosphor with enhanced efficiency using a resonant cavity (RC) structure. Phosphors are color conversion materials essential in modern optical devices, and the newly developed phosphor demonstrated a color conversion efficiency 29 times higher than conventional phosphors. It is expected to be utilized in future smart glasses, virtual reality (VR), and augmented reality (AR) display devices.
Professor Jeon Heon-su, Department of Physics and Astronomy, Seoul National University. [Photo by Seoul National University]
On the 30th, a research team led by Professor Jeon Heon-su from the Department of Physics and Astronomy at Seoul National University and Professor Park Yeon-sang from the Department of Physics at Chungnam National University announced the development of a new phosphor utilizing the resonant cavity effect. The research results were published in "Nature Communications," a sister journal of the world-renowned journal Nature.
Phosphors are essential components applied on light-emitting devices such as LEDs in modern display devices. In previous research, the team demonstrated that combining a nanophotonic structure called a photonic crystal (PhC) with colloidal quantum dots (CQD) could dramatically increase color conversion efficiency. However, challenges such as high-cost processes and achievable color conversion efficiency remained.
In this study, the researchers overcame major issues through the resonant cavity structure. The resonant cavity structure is fabricated by stacking thin films vertically and is used in lasers and photodetectors, but according to the research team, it had not been applied to increase the absorption rate of fluorescent materials. Therefore, the team constructed a resonant cavity phosphor by inserting an ultra-thin quantum dot film less than 40 nm thick between two distributed feedback reflectors (thin-film optical reflectors composed of alternating layers of two materials with different refractive indices). As a result, the maximum light absorption rate by the quantum dots reached 87%, and the final color conversion efficiency increased 29-fold.
The researchers explained, "The resonant cavity phosphor developed through this study has a drastically reduced overall thickness," adding, "Compared to conventional photonic crystal phosphors, it features a simpler structure, easier fabrication process, and superior performance."
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