Bright all-solution-processed CsPbBr3 perovskite light emitting diodes optimized by quaternary ammonium salt

Perovskite light-emitting diodes (PeLEDs) prepared by the all-solution-process are gradually coming into view due to their low cost and flexible production process. However, the performance of CsPbBr3 device is limited by the high non-radiative recombination losses due to incomplete surface coverage and grain defects. Here a quaternary ammonium salt, tetrabutylammonium hexafluorophosphate (TBA-PF6) was simultaneously introduced into perovskite emission layers (CsPbBr3) and electron transport layer (TPBi (1,3,5-Tris(1-phenyl-1H-benzimidazol-2-yl) benzene) dissolved in ethyl acetate). As a result, the morphology and luminescence of CsPbBr3 films were improved, and the energy level of TPBi was more conducive to charge transport. Consequently, the maximum luminance and current efficiency of the modified green-emitting PeLEDs are improved. Furthermore, the optimized device had an operating life of more than 20 min at an initial luminance of 1230 cd/m2. This work provides a simple and easy method to be scaled up for the development of low-cost all-solution-processed PeLEDs. Introduction of TBA-PF6 into CsPbBr3 and TPBi improves the brightness and operational stability of the perovskite light emitting diodes. [Display omitted] •The introduction of TBA-PF6 into CsPbBr3 PeLED achieves to reduce the grain size and shrink the roughness of the films.•The energy levels of ETL are lowered after doping TBA-PF6 into TPBi, which is more favorable for charge transport.•The improvement of the stability of the optimized device is attributed to the enhanced resistance to water erosion.