Metal Halide Perovskite Light‐Emitting Devices: Promising Technology for Next‐Generation Displays

Abstract

As the requirements and expectation for displays in society are growing, higher standards of the display technology are proposed, including wider color gamut, higher color purity, and higher resolution. The recent emergence of light-emitting halide perovskites has come with numerous advantages, such as high charge-carrier mobility, tunable emission wavelength, narrow emission linewidth, and intrinsically high photoluminescence quantum yield. Recent advancement of perovskite-based light-emitting diodes (PeLEDs) as a promising technology for next-generation displays is reviewed. Here, how the attractive optical and electrical properties of perovskite materials can be translated into high PeLED performance are discussed, and working mechanisms and optimization approaches of both perovskite materials and the respective devices are analyzed. On the material side this includes the control of size and composition of perovskites grains and nanocrystals, surface and interface passivation, doping and alloying, while on the device side this includes the interfacial engineering and energy level adjustments, and photon emission enhancement. Several challenges such as performance of blue PeLEDs, the environmental and operational stability of PeLEDs, and the toxicity issues of lead halide perovskites are discussed, and perspectives on future developments of perovskite materials and PeLEDs for the display technology are offered.

Co‐Interlayer Engineering toward Efficient Green Quasi‐Two‐Dimensional Perovskite Light‐Emitting Diodes

“…So far, intensive research has been done to search for appropriate interlayer materials in the field of quasi‐2D perovskites. [ 28,29 ] Most of them mainly focus on the strategy by using single‐interlayer ligands or combination with polymer additives to form insulating surroundings. Nevertheless, the rational design rule for the interlayer ligands is still open to discussion.…”

A Lead‐Free All‐Inorganic Metal Halide with Near‐Unity Green Luminescence

“…During the past few years, lead halide perovskites have received considerable attention as a promising candidate owing to their remarkably high photoluminescence quantum efficiencies (near‐unity for blue, green, and red light‐emission), [ 3–5 ] low defect density as well as potential to be made at low cost via facile solution processing. [ 6–10 ] So far, the record of the external quantum efficiency of green LEDs based on lead halide perovskites has surpassed 20%, [ 11 ] approaching the performance of organic LEDs. However, the inherent toxicity of element lead is still a bottleneck to their further commercial applications, motivating considerable interest in identifying lead‐free alternatives.…”

Efficient perovskite nanocrystal light-emitting diodes using a benzimidazole-substituted anthracene derivative as the electron transport material

“…5,15 Unfortunately, to date, their LED performance remains on the relatively low side. 7,[16][17][18] The mechanisms lowering the efficiency of perovskite nanocrystal-based devices are still not very well-understood. [19][20][21][22][23] Several possible causes have been proposed, including (i) nonradiative recombination losses due to the surface defects on the nanocrystal surface, [23][24][25][26][27] (ii) the leakage current induced by the incomplete surface coverage, 28,29 and (iii) the imbalance of carrier injection that results in a high degree of efficiency rolloff at high luminance.…”