Solution-processed spin organic light-emitting diodes based on antisolvent-treated 2D chiral perovskites with strong spin-dependent carrier transport.

Abstract

Chiral perovskites, which are applied to spin organic light-emitting diodes as a spin-induced spin selectivity (CISS) layer, have attracted increasing amounts of attention. A device based on a thicker perovskite CISS layer leads to strongly spin-polarized EL emission. However, chiral perovskite films suffer from poor device performance due to difficulties in carrier injection and film quality. The effects of antisolvent dripping on the chiroptical properties of chiral perovskite films were investigated. The rapid crystallization of chlorobenzene (CB)-treated films generated a high-quality film with fewer halide vacancies and a much greater strength of asymmetric hydrogen bonding. Accordingly, the inorganic structural distortion is greater, resulting in greater chiroptical activity. The chiral perovskite thickness affects the circularly polarized electroluminescence (CP-EL) of spin-OLEDs. The statistics relating device performance and thickness are presented. The spin current polarization degree of chiral perovskites reaches approximately 86%. The maximum CP-EL asymmetry factor (g CP-EL) is 2.6 × 10^-2 and maximum external quantum efficiency (EQE) of the spin-OLED device is 3.68%. Spin OLED devices based on chiral perovskites can be manipulated and controlled by thickness and antisolvent treatment. g_CPEL intensities for devices based on CB-treated chiral perovskite films can be increased by about 1.75 times compared with devices based on untreated films.