Lead‐free metal halide perovskites for light‐emitting diodes

Abstract

Metal halide perovskites (MHPs) have been developing rapidly in recent years due to their outstanding optoelectronic properties and tremendous contributions from worldwide researchers. The external quantum efficiencies of perovskite light-emitting diodes (Pero-LEDs) have all exceeded 20% for the green, red, and near-infrared emitting ones. However, the toxicity and instability issues of the lead-based MHPs are still big problems limiting their practical applications. The applications of the lead-free MHPs (LFMHPs) are emerging as one of the most promising strategies to tackle these issues. Compared with lead-based MHPs, the LFMHPs show better environment stability and broader emission regions from the violet to near-infrared wavelength. Thanks to numerous contributions made by the researchers, great progress has already been made for the LFMHPs. For example, the photoluminescence quantum yield has reached near 100%. However, the performances of the lead-free Pero-LEDs are still lagging compared with their lead-based counterparts. In this review, we comprehensively summarize the synthesis developments of LFMHPs and their applications in the down-conversion white LEDs and electroluminescent Pero-LEDs. Moreover, some suggestions and outlooks of the lead-free Pero-LEDs developments are proposed in the end.

2D PEA2SnI4 Inkjet-Printed Halide Perovskite LEDs on Rigid and Flexible Substrates

“…Halide perovskites (HPs) have attracted attention over the past decade due to their excellent optoelectronic properties in the field of photovoltaics (PV) and light-emitting diodes (LEDs). , Here, perovskite-based light-emitting diodes (PeLEDs) show external quantum efficiencies (EQE) exceeding 20%. , Recently, there has been much work focused on lead-free HPs, mostly in PVs, as the most promising strategies to tackle toxicity issues. However, development of Pb-free PeLEDs has received less attention mostly due to their intrinsic lower stability in comparison with their Pb-containing PeLED counterparts.…”

Environment‐Friendly Perovskite Light‐Emitting Diodes: Progress and Perspective

“…For perovskites, toluene, chlorobenzene, dichloromethane, diethyl ether, and methanol act as poor solvents. [45][46][47] Chao's group found that the CsSnI 3 perovskite films showed a sponge-like morphology which were synthesized by one-pot solution method. These sponge-like films exhibited poor performance and existed many pinholes.…”

“…As using different materials for HTL and ETL will directly affect the energy level, the structure of lead-free PeLEDs should be designed for optimizing energy level alignment, which needs to find more proper charge transport materials. [47] Further researches should be underway to find effective approaches for preparing high-performance lead-free PeLEDs. Figure 6.…”

High‐Resolution Patterned Functionalization of Slippery “Liquid‐Like” Brush Surfaces via Microdroplet‐Confined Growth of Multifunctional Polydopamine Arrays

“…In principle, patterned perovskites with single crystalline, 2D, or self-assembled nanostructures might also be realized using the same approach for optoelectronic devices. [69][70][71] And the dewetting process may provide great promise to generate various arrays of plasmonic, magnetic, or catalytic nanomaterials to functionalize slippery surfaces.…”