Charge Carrier Recombination Dynamics in MAPb(Br x Cl1–x )3 Single Crystals

Understanding carrier recombination processes in MAPb­(Br x Cl1–x )3 crystals is essential for their photoelectrical applications. In this work, carrier recombination dynamics in MAPb­(Br x Cl1–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(Br x Cl1–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(Br x Cl1−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(Br x Cl1–x )3 single crystals.