LAUSR

The exceptional structural tunability of organic metal halides endow themselves with fascinating electronic and photophysical properties, providing a lot of room to exploring abundant applications. In this work, for the first time, a novel organic metal halide (C4H9NH3)2MnI4 single crystal, is reported with reversible thermo-induced luminescent chromism within a wide temperature range. The (C4H9NH3)2MnI4 single crystal exhibits two emission peaks at 550 and 672 nm, which are assigned to d-d transition of Mn2+-centered tetrahedra and self-trapped excitons, respectively. The temperature-dependent emission color change is attributed to the thermo-induced trapping and detrapping process of the self-trapped exciton. Especially, (C4H9NH3)2MnI4 exhibits the maximum photoluminescence quantum efficiency value of up to 68% at 70 °C. The disclosed interacted photoluminescence decay mechanisms may enlighten further design of organic metal halides for optical thermometry.