Highly Emissive Self-Trapped Excitons in Fully Inorganic Zero-Dimensional Tin Halides

摘要

The spatial localization of charge carriers to promote the formation of bound excitons and concomitantly enhance radiative recombination has long been a goal for luminescent semiconductors. Zero-dimensional materials structurally impose carrier localization and result in the formation of localized Frenkel excitons. Now the fully inorganic, perovskite-derived zero-dimensional Sn-II material Cs4SnBr6 is presented that exhibits room-temperature broad-band photoluminescence centered at 540 nm with a quantum yield (QY) of 15 +/- 5%. A series of analogous compositions following the general formula Cs(4-x)A(x)Sn(Br1-yIy)(6) (A=Rb, K; x = 1, y = 1) can be prepared. The emission of these materials ranges from 500 nm to 620 nm with the possibility to compositionally tune the Stokes shift and the self-trapped exciton emission bands.