Vapor‐Assisted In Situ Recrystallization for Efficient Tin‐Based Perovskite Light‐Emitting Diodes

Abstract

Tin‐based perovskites are a promising candidates to replace their toxic lead‐based counterparts in optoelectronic applications, such as light‐emitting diodes (LEDs). However, the development of tin perovskite LEDs is slow due to the challenge of obtaining high‐quality tin perovskite films. Here, a vapor‐assisted spin‐coating method is developed to achieve high‐quality tin perovskites and high‐efficiency LEDs. It is revealed that solvent vapor can lead to in situ recrystallization of tin perovskites during the film‐formation process, thus significantly improving the crystalline quality with reduced defects. An antioxidant additive is further introduced to suppress the oxidation of Sn2+ and increase the photoluminescence quantum efficiency up to ≈30%, which is an approximately fourfold enhancement in comparison with that of the control method. As a result, efficient tin perovskite LEDs are achieved with a peak external quantum efficiency of 5.3%, which is among the highest efficiency of lead‐free perovskite LEDs.

Advances in electrically driven light-emitting diodes based on lead-free metal halides

“…1a. 27 In addition to the easy oxidation of Sn 2+ , Sn-based LEDs also have an inferior film morphology, which leads to poor device stability and reproducibility. Therefore, they reported a simple and convenient method using Quasi-2D (PEAI) x (CsI) y (SnI 2 ) z perovskite multiple quantum wells (MQWs) to achieve efficient and stable lead-free LEDs.…”

“…The VASC method is conducted by adding 200 mL of mixed solvent to the spin-coater to form solvent vapor before depositing perovskites. Copyright 2022, Wiley-VCH 27. (b) Electroluminescent (EL) spectra of PEA 2 SnI 4 LEDs.…”

Tautomeric Mixture Coordination Enables Efficient Lead-Free Perovskite LEDs

“…Exploration of highly efficient and stable Pb-free perovskite-based light emitters has been an urgent research topic, and Sn-based perovskite has been regarded as a promising candidate because Sn has a similar valence electron configuration and ionic radius as Pb 14,15 . Nonetheless, the endsville EQEs of Sn-based PeLEDs are seriously lagging behind those of Pb-based counterparts [16][17][18] . Most strategies adopted to improve Sn-based PeLEDs have been focusing on inhibiting the oxidation of Sn 2+ by introducing Sn compensators 19 and reducing agents 20 .…”

“…Furthermore, the residual chemical agents often destroy the orderliness of the crystal lattice of Sn perovskites, resulting in Anderson localization 21 , which is detrimental to the optoelectronic properties. Morphological control 18 and solvent engineering 17 methods have also been developed to increase the EQE of Sn-based PeLEDs of up to 5.4%. The low EQE of Sn-PeLEDs implies a limited understanding of the intrinsic instability of Sn 2+ , and more in-depth studies are needed to further enhance both EQE and stability of Sn-based PeLEDs.…”

Solvent Evaporation Induced Large-Scale Synthesis of Cs4PbBr6 and CsPbBr3 Microcrystals: Optical Properties and Backlight Application for LEDs

“…Perovskites, especially metal halide perovskites are enthusiastically employed in numerous fields such as Flexible-electronics, photodetectors, , solar cells, lasers, LEDs, and photo catalysis due to their remarkable optoelectronic properties such as high charge carrier mobility, diffusion length, tunable band gap, and ease of synthesis via low temperature solution processing methods. , Among them, perovskite based light emitting diodes (p-LEDs) have gained much attention as powerful display devices due to their enhanced external quantum efficiency (EQE) from 1% to more than 23% as reported by recent literature . One of the major drawbacks that hinder the upliftment of EQE in perovskites is the non-radiative recombination rates arising from crystal defects .…”