Composition‐Dependent High‐Performance Phototransistors Based on Solution Processed CH3NH3PbI3/ZnO Heterostructures

Abstract

AbstractRecently, hybrid organic−inorganic perovskites have emerged as promising photo‐sensing materials for next‐generation solution‐processed phototransistors, achieving high responsivity, detectivity, and fast response. Here, a phototransistor that can detect visible light using a low‐cost, solution processed methylammonium lead iodide/zinc oxide (CH3NH3PbI3/ZnO) heterostructure is reported. While typical ZnO thin‐film transistors (TFTs) do not show any photocurrent under visible light illumination, CH3NH3PbI3 (MAPbI3) coated ZnO TFTs exhibit substantial photocurrent. Additionally, the optical, morphological, and structural characteristics of the light‐absorbing layers are further controlled by altering the precursor ratio of methylammonium iodide and lead (II) iodide (MAI:PbI2), which in turn affects the photosensitivity. Stoichiometric composition (MAI:PbI2 = 1:1) of MAPbI3 demonstrates optimal characteristics with a responsivity of 234 A/W and a high detectivity of 3.74 × 1013 Jones under white light illumination. The high photo‐responsivity and detectivity result from the combination of the suitable optoelectronic properties of the stoichiometric MAPbI3 film and its smooth interface with the ZnO channel.