Mesoscopic CH3NH3PbI3/TiO2 heterojunction solar cells

ABSTRACT: We report for the first time on a hole conductor-free mesoscopic lead iodide CH3NH3PbI3(perovskite)/TiO2 heterojunction solar cell, produced by deposition of perovskite nanopar-ticles from a solution of CH3NH3I and PbI2 in -butyrolactone on a 400nm thick film of TiO2 (ana-tase) nanosheets exposing (001) facets. An Au film was evaporated on top of the CH3NH3PbI3 served as a back contact. Importantly, the CH3NH3PbI3 nano-particles act assumes here simultaneously the role of light harvester and hole conductor rendering super-fluous the use of an additional hole transporting material. The simple mesoscopic CH3NH3PbI3/TiO2 heterojunction solar cell shows impressive photovol-taic performance with short circuit photocurrent (Jsc) of 16.1 mA/cm2, an open circuit photovoltage (Voc) of 0.631 V and a fill factor (FF) of 0.57, corre-sponding to a light to electric power conversion effi-ciency (PCE) of 5.5 % under standard AM 1.5 solar light of 1000 W/m2 intensity. At a lower light intensi-ty of 100W/m2 a PCE of 7.3 % was measured. The advent of such simple solution processed mesoscop-ic heterojunction solar cells paves the way for new advances to realize low cost, high-efficiency solar cells