Low-temperature photoluminescence spectroscopy of CH3NH3PbBrxCl3-x perovskite single crystals

Organic-inorganic halide perovskite (OIHP) has attracted tremendous attention due to its potential applications in optoelectronics such as light emitting device and photodetector. Here, we have grown high quality CH3NH3PbBrxCl3-x perovskite single crystals and investigated the luminescence mechanism of these materials. The results indicate that optical properties of CH3NH3PbBrxCl3-x perovskite materials are strongly depend on the temperature and the dope concentration. Free exciton recombination emission has dominant contribution to luminescence spectra of materials at orthorhombic structure, as bound exciton recombination emission to the spectra of materials at cubic structure. Based on temperature-dependent photoluminescence, the exciton binding energy of CH3NH3PbCl3 and CH3NH3PbBr0.3Cl2.7 are calculated as about 22.9 meV and 27.1 meV, respectively.