Crystallization Management with Tailored Thermal Annealing for Quasi-Two-Dimensional Perovskites Light-Emitting Diodes

Abstract

Quasi-two dimensional (quasi-2D) perovskite has attracted considerable attention due to its large exciton binding energy and quantum confinement effect, which make it promising for use in light-emitting diodes (LEDs). However, quasi- 2D perovskite films formed by solution processes suffer from inefficient energy transfer caused by undesired phase mixtures, poor crystallinity, and structural defects due to rapid crystal growth, leading to increased non-radiative recombination and reduced device performance. To minimize the defects in perovskite, the crystal growth of quasi-2D perovskite was adjusted by thermal annealing processes. Meanwhile, the grain size can be controlled by adjusting the annealing conditions, which allows for tuning the emission wavelength in the range of 507-519 nm. By optimizing the thermal annealing conditions, quasi-2D perovskite LEDs (PeLEDs) showed a maximum luminance of 4730 cd m-2 and maximum external quantum efficiency of 15.5%, with an emission peak at 513 nm. The management of crystallization kinetics in quasi-2D perovskite promotes the practical application progress of PeLEDs.