Preparation and optoelectronic properties of multi-color high-efficiency CH3NH3Pb(BrxI1-x)3 perovskite light-emitting diodes

Abstract

Multi-color light-emitting materials are essential lighting and displays. In this study, mixed halide system was applied to precisely tune the bandgap of CH _3 NH _3 Pb(Br _x I _1- _x ) _3 , thus regulating the emission wavelength. PEABr was employed to change the phase structure and morphology of CH _3 NH _3 Pb(Br _x I _1- _x ) _3 perovskite thin films and improve the performance of multi-color perovskite light-emitting diodes (PeLEDs). Theoretical simulations through first-principles calculations and experiments demonstrate that multi-color PeLEDs can be achieved by adjusting the ratio of bromine (Br) and iodine (I) atoms in the CH _3 NH _3 Pb(Br _x I _1- _x ) _3 perovskite. The maximum luminance of PEABr-modified green PeLEDs reached 7108 cd m ^−2 , with a maximum current efficiency of 8.25 cd A ^−1 and a maximum external quantum efficiency (EQE) of 1.62%, which were greatly improved compared to the reference device without PEABr. In addition, the luminance of orange-yellow and red mixed-halide PeLEDs both exceed 100 cd m ^−2 . The results demonstrate that the use of PEABr additive can effectively control the morphology of CH _3 NH _3 Pb(Br _x I _1- _x ) _3 crystals, and high-performance multi-color light-emitting devices can be achieved by combining with mixed halide system. The electroluminescence spectra showed that the emission range of the devices covered the wavelength region of 520–720 nm, demonstrating their good application prospects in the field of multi-color displays.

Keywords

• perovskite light-emitting diodes
• multi-color
• PEABr
• mixed halide system