Component engineering to achieve reversible luminescence switching of tetramethylammonium manganese halides

Metal halide perovskites have attracted extensive attention due to their wide application in many fields such as solar cells, light-emitting diodes, and photodetectors, etc. Herein, we separately synthesize green-emitting TMAMnCl3 and red-emitting TMA2MnCl4 (TMA = tetramethylammonium chloride) single crystals by controlling the feeding ratios of MnCl2/TMACl precursors via a slow evaporation crystallization method, respectively. Further, thereversible luminescence switching between TMAMnCl3 and TMA2MnCl4 single crystals can be achieved by adding corresponding raw MnCl2 or TMACl precursors due to the transformation of crystal structures. The structural differences between the different coordination environments are found to play a key role to the different optical properties of the two crystal structures. The light-emitting diodes devices prepared based on the two kinds of materials show excellent performance at different currents and voltages. Our research sheds light on controlling the structural transformation and luminescence switching of manganese-based organic–inorganic hybrid perovskites.