Charge Carrier Recombination Dynamics in MAPb(BrXCl1-X)3 Single Crystals

Understanding carrier recombination processes in MAPb(BrxCl1-x)3 crystals is essential for their photoelectrical applications. In this work, carrier recombination dynamics in MAPb(BrxCl1-x)3 single crystals were studied by steady-state photoluminescence (PL), time-resolved photoluminescence (TRPL), and time-resolved microwave photoconductivity (TRMC). By comparing TRPL and TRMC, we find TRPL of MAPb(BrxCl1-x)3 (x < 0.98) single crystals is dominated by a hole trapping process while the long-lived component of TRMC is dominated by an electron trapping process. We also find both electron and hole trapping rates of MAPb(BrxCl1-x)3 (x < 0.98) crystals decrease with an increase in Br content. A temperature-dependent PL study shows there are shallow trap states besides the deep level trap states in the MAPb(Br0.82Cl0.18)3 crystal. The activation energy for holes in shallow trap states detrapped into the valence band is -0.1 eV, while the activation energy for free holes to be trapped into deep trap states is -0.4 eV. This work provides insight into carrier recombination processes in MAPb(BrxCl1-x)3 single crystals.