The Next Generation of Photonic Sources – Light-Emitting Devices
일 시 : 2022년 04월 13일 수요일 16:30
연 사 : 노 광 동 교수 (이화여자대학교 물리학과)
장 소 : 온라인 (https://us02web.zoom.us/j/89360381750)
HOST : 정 문 석 교수님
초 록
Over the past decade, significant progress has been made in semiconductor research for efficient light-emitters. Using low-cost methods of solution-processed chemistry, nano-materials such as colloidal quantum dots and perovskites have emerged as a technologically viable material candidate for the next generation of luminescent materials. Hence, this talk will first address the introduction and fundamental optical and electrical properties showing wavelength-tunable bandgap, narrowband emission, high internal quantum efficiency etc. These intriguing properties have enabled to fabricate perovskite-based LEDs with more than 20% of external quantum efficiency. However, despite successful achievements of perovskites in optoelectronic applications, several drawbacks still hinder further development for visible light emitters such as material instability under ambient conditions, phase separation of halide, low thermal conductivity, and limited lasing operations. Thus, in the second part of this talk, several approaches, and recent reports to overcome these difficulties will be presented. It has been shown that our engineered mixed-halide perovskites can suppress the halide redistribution phenomenon by proper selection of additive capping layer, leading to develop efficient wavelength-tunable LEDs and single-mode distributed feedback lasers at room temperature for the first time. Also, design principles for realizing lasing operation from a functional perovskite LED device under intense electrical excitation will be discussed.