Bright Lead-Free Inorganic CsSnBr₃ Perovskite Light-Emitting Diodes

Abstract

Tin-based perovskites have emerged as lead-free alternatives, but their application in perovskite light-emitting diodes (PeLEDs) has been limited due to the low chemical stability and inhomogeneity of the inorganic CsSnBr 3 films using solution processing. Here, we demonstrate bright (∼160 cd m −2 ) CsSnBr 3 PeLEDs made by introducing co-additives consisting of SnF 2 and a grain-growth inhibitor (1,3,5-tris(Nphenylbenzimidazol-2-yl)benzene). The use of co-additives increased the number of nucleation sites during the crystallization process of CsSnBr 3 , and consequently yielded uniform CsSnBr 3 films with decreased grain size and improved defect passivation. The crystallization-controlled CsSnBr 3 PeLEDs had a maximum luminance of ∼160 cd m −2 , i.e., ∼7500 times brighter than than that of the control devices (without additive, 0.02 cd m −2 ), and a long device lifetime of ∼30 h at 58 cd m −2 . Our work suggests that control of the crystallization of CsSnBr 3 during film formation is an important requirement to increase the luminescence efficiency and stability of tin-based PeLEDs.

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

“…1e and f). 29 Notably, the emission range of Sn-based LEDs can reach the near-infrared emission region (>810 nm), which is beyond the range of PeLEDs of lead( ii ) halides. Dou et al found that Sn( ii ) based organic perovskite hybrid quantum wells (HQWs) could enhance charge transport and greatly inhibit ion migration by adding an organic barrier with a small band gap to the HQWs (HQW configuration in Fig.…”

“…The LEDs with SnF 2 : TPBI co additive are 13 times brighter than LEDs with SnF 2 only (L E 107 cd m À2 ). Copyright 2022, American Chemical Society 29. (f) Operational lifetime of CsSnBr 3 LEDs.…”

“…(f) Operational lifetime of CsSnBr 3 LEDs. Copyright 2022, American Chemical Society 29. (g) Schematic of relative band alignment of organic (BTm + ) and inorganic ([SnI 4 ] 2À ) layers within 2D hybrid perovskites.…”

Various approaches to synthesize water-stable halide PeNCs

“…Solution-processed halide PeNCs have already set benchmarks in the research on optical devices 1–4 and optoelectronic devices, 5–7 especially solar cells 8–11 (making them competitors to Si-based solar cells in terms of efficiency) and solid-state light-emitting diodes (providing outstanding colour purity and high luminescence efficiency). 12–17 Despite the relatively short period of research, perovskite nanocrystals (PeNCs) achieved almost ∼30% power conversion efficiency (PCE), 10 near-unity photoluminescence quantum yield (PLQY), 14,18 large carrier lifetime (≥1 μs), 19 and long carrier diffusion length (in the range of μm). 20 However, instability in the presence of water impedes large-scale commercialization or daily use of products.…”

Ultra-stable blue-emitting lead-free double perovskite Cs2SnCl6nanocrystals enabled by an aqueous synthesis on a microfluidic platform

“…[7][8][9] Recently, several antioxidants were used to improve the stability of Sn-based perovskites and the corresponding devices. 10,11 However, improving the environmental stability of Sn-based LFHP NCs still remains challenging.…”