The efficiency and stability issues of perovskite light-emitting diodes, especially at high brightness, need to be urgently solved for displays and lighting applications. Herein we present a simple chemical washing method called solvent sieve to resolve the phase dimension issue of metal halide perovskites. After being sieved, undesirable defect-rich low- n phases are selectively screened out of perovskite multi-quantum-well structures. With better intrinsic structure refinement, the sieved perovskites demonstrated not only a record external quantum efficiency, current efficiency, and T 50 lifetime of 29.5%, 127.4 cd A −1 , and 18.67 h at 12,000 cd m − 2 (the equivalent of over 50,317 h or 5.7 years at 100 cd m − 2 ), respectively, with a maximum luminance of over 147,872.8 cd m − 2 , but also extraordinary resistance to air and moisture, maintaining over 75% of film photoluminescence quantum yield and 80% of device EQE after being stored at ambience for 100 days. The simple solvent sieve treatment we reported here confirms the feasibility of metal halide perovskites for luminescence and unleashes the efficiency and stability potentials of high-brightness perovskite light-emitting diodes for future commercial applications.
Li Luo,Zhen Fan,Zhaobin Zhang,Danyang Liu,Guofa Li,Lishuang Wang,Bingsuo Zou
SnO2 nanoparticles (NPs) have been used as an electron transport layer (ETL) in quantum dot light-emitting diodes (QLEDs) to achieve stable and high-performance devices. However, SnO2 NPs with high electron mobility cause the problem of imbalanced charge injection and transport in QLEDs. Meanwhile, the SnO2 NPs synthesized at low temperature have hydroxyl (−OH) groups, which could damage the performance of QLEDs. Here, Zn doping was applied to modulate the properties of SnO2 NPs and achieve better carrier balance in green CdSe/ZnS QLED. The maximum current efficiency (CE) of QLED with 5 wt % Zn-doped SnO2 NPs is 2.3-fold higher than that of SnO2-based QLED. In addition, a small-molecule 4,4′-bis(carbazole-9-yl)-1,1′-biphenyl (CBP)-mixed poly(9-vinylcarbazole) (PVK) layer was used as a hole transport layer to facilitate the hole injection and charge balance. As a result, a maximum external quantum efficiency (EQE) of 5.03% is obtained for the best performance device. The T50 lifetime at a luminance of 100 cd/m2, for a device based on 5 wt % Zn-doped SnO2 ETL, is 9141 h, which is 2.29-fold longer than the reference one. This work provides a new strategy to obtain high-performance and stable display arrays.
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