Boosting the Efficiency of Quasi-2D Perovskites Light-emitting Diodes by Using Encapsulation Growth Method

Abstract The fabrication of perovskite film is crucial for achieving efficient perovskite photoelectric device. Herein, a simple and novel encapsulation growth method was applied to prepare high-quality quasi-2D perovskite films with advantages of compact and uniform morphology, high crystallinity with lower defect density, enhanced photoluminescence quantum yield (PLQY) and optimized multidimensional domain distribution and crystallite orientation for perovskite light-emitting diodes (PeLEDs). The encapsulation growth method was found to decrease the proportion of the low-dimensional (n=1,2,3) domains while increasing the high-dimensional domains content with randomly-oriented crystals, which simultaneously enhanced the overall energy landscape effect and charges transport within the quasi-2D perovskite films, and the PLQY of the quasi-2D perovskites significantly improved from 9.2% to 60.0%. Finally, an efficient flexible green PeLEDs was obtained with a high luminous efficiency (LE) of 47.1 cd/A, and a luminance brightness of 8,300 cd/m2, and an efficient sky-blue PeLEDs was also achieved with record EQE of 12.8% by using encapsulation growth method. This encapsulation growth method provides a promising strategy for boosting the efficiency of quasi-2D PeLEDs.