Conformational Disorder of Organic Cations Induces Charge Localization in 3D Lead Iodide Perovskitoids toward Sensitive Photodetectors

Three-dimensional (3D) hybrid halide perovskitoids have drawn intense attention in the optoelectronic fields. Therefore, understanding the structural effects on the charge carrier behavior is essential for device optimization. Herein, we establish the correlation between the conformational disorder of cations and the charge carrier property in 3D perovskitoids using computational and experimental investigations. It is shown that the conformational disorder of N,N′-dimethyl-1,3-propane diammonium (M2PDA) cations induces great distortion of the [Pb2I10]6– inorganic framework in 3D (M2PDA)Pb2I6, leading to distinct charge localization. Moreover, the cation configuration disorder suppresses defect formation, thereby reducing lattice microstrain. These modifications effectively elongate the carrier lifetime and diminish carrier scattering to facilitate charge carrier transport. As a result, a photodetector assembled from (M2PDA)Pb2I6 single crystals achieves a satisfying on/off current ratio of 1.42 × 104 and responsivity of 0.55 A W–1, ranking among the highest-performing devices based on 3D perovskitoids. Moreover, the (M2PDA)Pb2I6 single crystals display superior stability in 100% isopropanol.