Blue emission in a fluorinated 2D (C8H11FN)2PbBr4 perovskite with 11.17% photoluminescence quantum yield

Abstract

Halide perovskites have attracted significant interest in optoelectronics due to their exceptional luminescence properties, including narrow emission spectra and wide colour tunability, making them ideal candidates for a range of light-emitting applications. Among them, 2D halide perovskites offer enhanced stability and tunable optical characteristics through advanced structural design. In this study, we present a new 2D lead bromide perovskite, (C₈H₁₁FN)₂PbBr₄, featuring the halogenated A-site organic linker 4-fluoro-phenethylammonium bromide. This material exhibits a direct bandgap with narrow emission in the deep blue region, with a PLQY of 11.17%. The narrow emission is attributed to free excitonic emission, resulting in a rigid halogenated structure. Using a combination of temperature-dependent Raman and emission studies, the mechanism of photoluminescence is explained.