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Title:: Recent Developmentsof Lightings Based on Organic Semiconductors (Organic Lighting)

Author(s):: Dongdong Zhang; Yan Zhao; LianDuan; Yong Qiu*; Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry,Tsinghua University, Beijing 10084, China

Abstract:: Organic lightings based on white light-emitting diodes (WOEDs) are eco-friendly, safe and healthy area light sources, which are promising candidates for solid-state lighting. Development of high performance organic materials is essential to the development of WOLEDs. The performances of organic light-emitting materials have been significantly improved from fluorophors to phosphors, and to fluorophors with thermally activated delayed fluorescence (TADF). Performances of WOLEDs based on those materials are also gradually promoted. The earliest WOLEDs were based on small organic fluorophors. However, since only the singlet excitons can be used, the device efficienciesare low. Soon afterwards, the utilization of phosphors greatly increased the device efficiency. But the lifetimes of the all-phosphor WOLEDs are short due to the material stability issue of the blue phosphors. To combine the advantages of fluorophors and phosphors, hybrid WOLEDs are proposed, which is the most promising method nowadays. Recent researches onWOLEDs arefocused onimprovingthe over-all properties concerning high efficiency and long device lifetime. Here, we will give a reviewabout the development of the WOLEDs, divided into three parts based on the materials used: all fluorophors, all phosphors and fluorophor/phosphor hybrid WOLEDs.