The characteristics of I/Cl alloying structures in MAPbI3-xClx mixed-halide perovskites and their influences on the optoelectronic properties have been issues of long-standing controversy. In this work, by using on the time-dependent X-ray diffraction, 207Pb and 2H NMR, the authors investigated the I/Cl alloying structures and its long term stability in MAPbI3-xClx (x = 0.0 to 0.3) single crystals. It was found that Cl can substitute for I of the PbI3 inorganic lattice, leading to the tetragonal to cubic phase transition. Moreover, it revealed that the alloying structures of the MAPbI3-xClx crystals are metastable and may decompose over time.
- Wen-Cheng Qiao
- Jianming Yang
- Ye-Feng Yao