A-site coordinating cation engineering in zero-dimensional antimony halide perovskites for strong self-trapped exciton emission

Low-dimensional hybrid halide perovskites represent a promising class of materials in optoelectronic applications because of strong broad self-trapped exciton (STE) emissions. However, there exists a limitation in designing the ideal A-site cation that makes the material satisfy the structure tolerance and exhibit STE emission raised by the appropriate electron-phonon coupling effect. To overcome this dilemma, we developed an inorganic metal-organic dimethyl sulfoxide (DMSO) coordinating strategy to synthesize a series of zero-dimensional (0D) Sb-based halide perovskites including Na3SbBr6 & BULL;DMSO6 (1), AlSbBr6 & BULL;DMSO6 (2), AlSbCl6 & BULL;DMSO6 (3), GaSbCl6 & BULL;DMSO6 (4), Mn2Sb2Br10 & BULL;DMSO13 (5) and MgSbBr5 & BULL;DMSO7 (6), in which the distinctive coordinating A-site cation [A(m)-DMSO6](n+) efficiently separate the [SbXz] polyhedrons. Advantageously, these materials all exhibit broadband-emissions with full widths at half maxima (FWHM) of 95-184 nm, and the highest photoluminescent quantum yield (PLQY) of 3 reaches 92%. Notably, compounds 2-4 are able to remain stable after storage of more than 120 d. First-principles calculations indicate that the origin of the efficient STE emission can be attributed to the localized distortion in [SbXz] polyhedron upon optical excitation. Experimental and calculational results demonstrate that the proposed coordinating strategy provides a way to efficiently expand the variety of novel high-performance STE emitters and continuously regulate their emission behaviors.