Is the replacement of “Pb” by “Cu” in methylammonium lead bromide possible?

Abstract

Substitution of hazardous “Lead” by environmentally benign “Copper” in the methylammonium lead bromide perovskite system is investigated in this work. Nanostructured CH3NH3Pb1-xCuxBr3 perovskite thin films exhibiting c-axis growth has been achieved by us. Evidence for c-axis growth in the copper substituted thin films were obtained from HRTEM analysis. Using a two-step process sequence consisting of a non-aqueous emulsion-based technique for nano-power synthesis followed by a drop-cast technique was optimized for thin film growth. Structural and optical characterizations confirmed the formation of copper substituted methylammonium lead bromide in the orthorhombic structure with preferential orientation along the (040) plane. The average grain size was estimated to be ∼20 nm. Optical characterization identified the optical band gap to be ∼2.46 eV with characteristic green photoluminescence at ∼534 nm. Photo response was obtained from a Glass/FTO/CH3NH3Pb1-xCuxBr3/Graphite/FTO/Glass device structure engineered by us. The photosensitivity of the device structure was observed to be 1299 which was nearly an order above the photosensitivity of the pristine counterpart.