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.