Amine-Based Passivating Materials for Enhanced Optical Properties and Performance of Organic–Inorganic Perovskites in Light-Emitting Diodes

Abstract

The use of hybrid organic-inorganic perovskites in optoelectronic applications are attracting an interest because of their outstanding characteristics, which enable a remarkable enhancement of device efficiency. However, solution-processed perovskite crystals unavoidably contain defect sites that cause hysteresis in perovskite solar cells (PeSCs) and blinking in perovskite light-emitting diodes (PeLEDs). Here, we report significant beneficial effects using a new treatment based on amine-based passivating materials (APMs) to passivate the defect sites of methylammonium lead tribromide (MAPbBr) through coordinate bonding between the nitrogen atoms and undercoordinated lead ions. This treatment greatly enhanced the PeLED's efficiency, with an external quantum efficiency (EQE) of 6.2%, enhanced photoluminescence (PL), a lower threshold for amplified spontaneous emission (ASE), a longer PL lifetime, and enhanced device stability. Using confocal microscopy, we observed the cessation of PL blinking in perovskite films treated with ethylenediamine (EDA) due to passivation of the defect sites in the MAPbBr.

Operational stability of perovskite light emitting diodes

“…In those experiments, the concentration of halides was found to increase in the electrode as well as the organic interlayer after electric poling. In addition, the formation of silver halide in the silver electrode has also been confirmed by x-ray photoelectron spectroscopy (XPS) (figure 4(c)) [59, 61] and x-ray diffraction (figure 4(d)) [81].…”

“…Therefore, suppressing grain boundary ion migration is very critical to the operational stability of perovskite LEDs, and defect passivation is the most effective approach. The commonly used passivation materials for perovskite are Lewis bases [29,81,113]. In perovskites, Pb 2+ is considered as Lewis acid containing an empty orbital that can accept the unbonded electron pair of a Lewis base, resulting in Lewis acid-base reaction [114].…”

Spontaneous Silver Doping and Surface Passivation of CsPbI3 Perovskite Active Layer Enable Light-Emitting Devices with an External Quantum Efficiency of 11.2%

“…The peaks located at 374.1 and 368.1 eV can be assigned to metal Ag 0 , while the 373.3 and 367.6 eV peaks are assigned to Ag + . 24 …”

Control of Interface Defects for Efficient and Stable Quasi‐2D Perovskite Light‐Emitting Diodes Using Nickel Oxide Hole Injection Layer

“…Metal halide perovskites (MHPs) have emerged as a promising class of materials for optically pumped lasers and light‐emitting diodes (LEDs) owing to their narrow emission spectrum and wide range of color tunability 1, 2, 3, 4, 5, 6, 7. To date, perovskite LEDs (PeLEDs) have recorded an external quantum efficiency (EQE) of up to 14.36% for green emissions6 and 12.7% for near‐infrared emissions 7.…”