A review of blue light emitting diodes for future solid state lighting and visible light communication applications

摘要

This paper reviews the rapid progress being made in the developments of organic/inorganic blue light emitting diodes (LEDs). Blue LEDs exhibits outstanding electrical and optical properties such as low forward driving voltage, high light output power, high brightness and high internal quantum efficiency (IQE). This article highlights the rapid advancements being made in the developments of organic/inorganic blue LEDs over the last five decades, efficiency enhancement techniques, efficiency droop in blue LEDs and the techniques to alleviate efficiency droop, recent developments in flexible blue LEDs, degradation mechanisms and reliability issues in blue LEDs, challenges in fabrication and packaging of blue LEDs and it also throw light on the applications of blue LEDs. Their uniqueness in terms of low forward driving voltage, high light output power and brightness and large modulation bandwidth has fuelled the incorporation of blue LEDs in a wide variety of applications such as visible light communication (VLC), solid state lighting (SSL), cellular phone displays, liquid crystal display backlights, flexible flat panel displays, outdoor full colour displays, indicators, smart TVs, projection displays and implantable biomedical devices.