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.