A hybrid lead iodide perovskite and lead sulfide QD heterojunction solar cell to obtain a panchromatic response

Abstract

We report for the first time on co-sensitization between CH₃NH₃PbI₃ perovskite and PbS quantum dots (QDs) in a heterojunction solar cell to obtain a panchromatic response from the visible to near IR regions. Following the deposition of the sensitizers on a TiO₂ film, an Au thin layer is evaporated on top as a back contact. Importantly, the CH₃NH₃PbI₃ nanoparticles and the PbS QDs used here simultaneously play both the role of a light harvester and a hole conductor, rendering superfluous the use of an additional hole transporting material. The mesoscopic CH₃NH₃PbI₃ (perovskite)–PbS (QD)/TiO₂ heterojunction solar cell shows an impressive short circuit photocurrent (J_sc) of 24.63 mA cm⁻², much higher than those of the individual CH₃NH₃PbI₃ perovskite and the PbS QD solar cells. The advent of such co-sensitization mesoscopic heterojunction solar cells paves the way to extend the absorbance region of the promising low cost, high-efficiency perovskite based solar cells.