Micromechanical chemical synthesis of two tin-based organic-inorganic hybrid perovskites for high color rendering index solid-state lighting.

Low-dimensional organo-inorganic hybrid halide perovskites with broadband emission characteristics are crucial for achieving excellent color rendering indices in solid-state lighting devices. Tin-based perovskites are promising lead-free candidates for their narrow band gaps, high charge mobility, and low toxicity. However, the susceptibility of Sn2+ to oxidation results in poor stability and strict synthetic conditions, posing a challenge for commercial applications. Herein, two tin-based perovskites, [Br(CH 2) 2 NH 3 ] 4 SnBr 6 ((BEA) 4 SnBr 6) and [Br(CH 2) 3 NH 3 ] 4 SnBr 6 ((BPA) 4 SnBr 6), were synthesized using an economical and environmental-friendly micromechanical chemical method under air conditions. Both perovskites exhibit a stable broadband orange-red light emission. Despite similar emission wavelengths (∼610 nm) and full width at half maximum (FWHM) (∼110 nm), they show a huge difference in lifetimes and photoluminescence quantum yields (PLQYs). (BPA) 4 SnBr 6 has a much longer lifetime (3.12 μs) and higher PLQY (79 %) than that of (BEA) 4 SnBr 6 due to its triplet self-trapped excitons (STEs) luminescence mechanism. Both compounds demonstrated good air stability; their photoluminescence intensity can be recovered to more than one times the initial value after 18 days in the air. Moreover, a stable warm white LED device with a color rendering index of 95.1 % was fabricated by coating blue phosphor BaMgAl 10 O 17 : Eu2+, green (Sr,Ba) 2 SiO 4 : Eu2+, and orange-red (BPA) 4 SnBr 6 on a commercial 365 nm LED chip. This study provides a novel approach for rapidly synthesizing high-performance tin-based perovskites and fabricating white LED devices with superior color rendering indices. • Two tin-based perovskites of (BEA) 4 SnBr 6 and (BPA) 4 SnBr 6 were prepared by a simple micromechanical chemical method. • The two tin-based perovskites showed excellent stability after 18 days in the air environment. • A broadband emission with a FWHM of ∼112–115 nm and a large Stokes shift of ∼264–270 nm was obtained. • The PLQY of (BPA) 4 SnBr 6 is up to 79 %. • The white LED prepared by (BPA) 4 SnBr 6 achieves a color rendering index of 95.1 %. [ABSTRACT FROM AUTHOR]