Dingyan Xu,Qun Wan,Siyao Wu,Yu Zhao,Xinglei Xu,Liang Li,Gufeng He
Lead halide perovskites have been considered promising materials for optoelectronic applications owing to their superior properties. CsPbBr3 nanocrystals (NCs) with a narrow particle size distribution and a narrow emission spectrum are synthesized by ligand-assisted re-precipitation (LARP), a low-cost and facile process. In inverted CsPbBr3 NC LEDs, a dual hole injection layer (HIL) of 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile (HAT-CN)/MoO3 is introduced to enhance hole injection and transport, because HAT-CN can extract electrons easily from the hole transport layer and leave a large number of holes there. The current and power efficiencies of the optimized device with a dual HIL are 1.5- and 1.8-fold higher than those of the single HIL device. It is believed that the dual HAT-CN/MoO3 HIL effectively promotes hole injection and has promise for application in many other devices.
Quantum dot light-emitting devices (QLEDs) exhibit unique advantages for high-resolution display applications. However, as pixel size decreases, challenges including insufficient hole injection and leakage current become increasingly pronounced, resulting in significant degradation in device performance. Herein, dual hole injection layers are constructed by self-assembly of an organic small molecular layer on conventional PEDOT:PSS to smooth the potential barrier, thus achieving more balanced carrier injection. An ultrafine inter-pixel isolation structure is designed as a charge blocking layer surrounding the photolithograpic pixels, with the purpose of effectively mitigating leakage current in the non-emitting region. The high-resolution devices show a high external quantum efficiency (EQE) of 19.6 % and a peak power efficiency (PE) of 20.63 lm/W, both of which significantly exceed the performance of the control device (EQE = 14.6 %, PE = 10.54 lm/W).
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