Fully Ambient Air Processed Perovskite Solar Cell Based on Co(Co,Cr)(2)O-4/TiO2 P-N Heterojunction Array in Photoanode

摘要

The enhanced electric field within a photovoltaic device can drain electrons to the interface of the electron transporting layer and sensitizer, thereby accelerating charge collection efficiency, reducing the recombination process, and, overall, resulting in solar-to-electric power conversion efficiency increment. Introduction of islands like p-n junction centers to the mesoporous-TiO2 texture could be an ideal strategy to improve stability and power conversion efficiency of perovskite solar cells. In this work, novel heterostructures of nanosized cobalt-chromium layered double hydroxide and TiO2 nano particles, with a nominal composition, were fabricated and utilized as perovskite underlayer film precursors. The champion device shows the highest power conversion efficiency with an improvement of 17.14%, compared to the 100% TiO2 paste composition. The offered interfacial distance between n-type TiO2 nanoparticles and the perovskite light harvester in p-n junction areas prevents direct contact between TiO2 and perovskite and, consequently, hinders photocatalytically caused perovskite degradation. Daily power conversion efficiency measurement indicates that the unencapsulated champion device which is kept in darkness in ambient air-maintains 92% of the initial efficiency after 25 days.