In situ preparation of highly luminescent Sb3+/Mn2+ co-doped Cs2KInCl6 lead-free double perovskite in PVDF matrix and application to white light emitting diode and anti-counterfeiting

Abstract

Recently, lead-free double perovskites have been regarded as a promising alternative to lead halide perovskite due to its wide emission band, environmental protection and stability, and is expected to become a series of rising star materials in the lighting field. However, the growth of most lead-free double perovskites occurs in the strong acid environment at present, which not only bring high cost and environment risk, but also hard to realize large-scale applications with powder products. Herein, we apply a strategy of in situ synthesis of lead-free double perovskites in a polymer matrix by using a small amount of precursors and relatively friendly DMSO solvent to obtain efficiently luminescent Sb3+/Mn2+ co-doped Cs2KInCl6/PVDF composite film in a large-area. The co-doping of Mn2+/Sb3+ into this inorganic double perovskite matrix makes microcrystals with good crystallinity and size distribution in this polymer. The as prepared co-doping composite film with Mn/Sb feeding ratio 16:1 shows the brightest white light emission at 320 nm excitation, with a photoluminescence quantum yield (PLQY) as high as 86.98%. The energy transfer (E-T) from the charge-transfer band to the triplet self-trapped exciton (STE) around Sb3+ and then to ferromagnetic (FM) coupled Mn2+ pair 3d state were confirmed by their temperature-dependent PL spectra and density functional theory calculations. Finally, a single-compound white light emitting diode with chromatic coordinate of (0.31, 0.33) and the fluorescent anti-counterfeiting labels could be fabricated based on this composite film with the best white emission. This work provides a new strategy for the application of lead-free double perovskites in the field of lighting and anti-counterfeiting.