Abstract
Recently, 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 (MAPbI(3)) 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 MAPbI(3) demonstrates optimal characteristics with a responsivity of 234 A/W and a high detectivity of 3.74 x 10(13) Jones under white light illumination. The high photo-responsivity and detectivity result from the combination of the suitable optoelectronic properties of the stoichiometric MAPbI(3) film and its smooth interface with the ZnO channel.