Zn-Doped SnO₂ NPs as Electron Transport Layer in Green CdSe/ZnS Quantum Dot Light-Emitting Diodes

Abstract

SnO 2 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, SnO 2 NPs with high electron mobility cause the problem of imbalanced charge injection and transport in QLEDs. Meanwhile, the SnO 2 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 SnO 2 NPs and achieve better carrier balance in green CdSe/ZnS QLED. The maximum current efficiency (CE) of QLED with 5 wt % Zn-doped SnO 2 NPs is 2.3-fold higher than that of SnO 2 -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 T 50 lifetime at a luminance of 100 cd/m 2 , for a device based on 5 wt % Zn-doped SnO 2 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.

Black Phosphorus Quantum Dots with Exposed (113) Planes on Chemiluminescent Luminol–K3Fe(CN)6 for Detection of Dopamine

“…However, noble metal nanomaterials are neither highly economical nor environmentally friendly. In recent years, quantum dots (QDs), as an excellent type of luminescent semiconductor nanocrystals, have become reliable materials for developing advanced analytical methods to assist the CL process, owing to their outstanding advantages of a wide spectral range, high quantum yield, and good photochemical stability. − For example, Kim and his co-workers constructed a new type of photosensor based on cesium lead bromide (CsPbBr 3 ) perovskite QDs, MoS 2 nanoflakes, and parylene-C film, which achieved hypersensitivity in the CL immunoassay on account of the high size confinement effect of CsPbBr 3 QDs and the blocking of trap states in the parylene-C film . Therefore, it can be a feasible idea to prepare QDs with unique catalytic activity to modify the traditional CL system and further investigate the possible reaction mechanism between QDs and the luminescent reagent.…”