Lai Chun-Feng, Lin Chun-Peng, Lee Yu-Chun
Department of Photonics, Feng Chia University, Taichung 407, Taiwan.
Lextar Electronics Corp., Hsinchu Science Park, Hsinchu 30075, Taiwan.
Nanomaterials (Basel). 2024 Jun 5;14(11):983. doi: 10.3390/nano14110983.
Recently, UVC LEDs, which emit deep ultraviolet light, have found extensive applications across various fields. This study demonstrates the design and implementation of thin films of three-dimensional photonic crystals (3D PhCs) as reflectors to enhance the light output power (LOP) of UVC LEDs. The 3D PhC reflectors were prepared using the self-assembly of silica nanospheres on a UVC LED lead frame substrate via the evaporation-induced method (side) and the gravitational sedimentation method (bottom), respectively. These PhCs with the (111) crystallographic plane were deposited on the side wall and bottom of the UVC LED lead frame, acting as functional materials to reflect UVC light. The LOP of UVC LEDs with 3D PhC reflectors at a driving current of 100 mA reached 19.6 mW. This represented a 30% enhancement compared to commercial UVC LEDs with Au-plated reflectors, due to the UVC light reflection by the photonic band gaps of 3D PhCs in the (111) crystallographic plane. Furthermore, after aging tests at 60 °C and 60% relative humidity for 1000 h, the relative LOP of UVC LEDs with 3D PhC reflectors decreased by 7%, which is better than that of commercial UVC LEDs. Thus, this study offers potential methods for enhancing the light output efficiency of commercial UVC light-emitting devices.
最近，发射深紫外光的UVC发光二极管在各个领域得到了广泛应用。本研究展示了三维光子晶体（3D PhC）薄膜作为反射器的设计与实现，以提高UVC发光二极管的光输出功率（LOP）。3D PhC反射器分别通过蒸发诱导法（侧面）和重力沉降法（底部），利用二氧化硅纳米球在UVC发光二极管引线框架基板上自组装制备而成。这些具有（111）晶面的PhC沉积在UVC发光二极管引线框架的侧壁和底部，作为反射UVC光的功能材料。在100 mA驱动电流下，带有3D PhC反射器的UVC发光二极管的LOP达到19.6 mW。与带有镀金反射器的商用UVC发光二极管相比，这代表着提升了30%，这是由于（111）晶面中3D PhC的光子带隙对UVC光的反射。此外，在60℃、相对湿度60%的条件下进行1000小时老化测试后，带有3D PhC反射器的UVC发光二极管的相对LOP下降了7%，这比商用UVC发光二极管的情况要好。因此，本研究为提高商用UVC发光器件的光输出效率提供了潜在方法。
