MAPbI₃ microneedle-arrays for perovskite photovoltaic application

Methyl-ammonium lead iodide perovskite (MAPbI₃) was synthesized in the form of micro-needles via a hydrothermal route at a low temperature of 100 °C in a two-step procedure for the first time. The results exhibit that the amount of the surfactant is crucial for the synthesis of the MAPbI₃ nanostructures with well-controlled morphologies. In contrast to bulk MAPbI₃, the one-dimensional (1-D) micro-needle perovskite with a diameter of 200 nm showed an improved hole injection from the perovskite to the hole transporting layer (HTL), providing a unique platform at the perovskite/HTL interface. The best performing device employing MAPbI₃ perovskite micro-needles yielded stable and hysteresis-free devices with a best power conversion efficiency of (PCE_best) of 17.98%. The current findings highlight the potential of perovskite micro-needles as novel absorber systems and lay the basis for future commercialization.