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Fully Ambient Air Processed Perovskite Solar Cell Based on Co(Co,Cr)₂O₄/TiO₂ P–N Heterojunction Array in Photoanode

Pourradi, Hadi, Ghani, Kamal, Mahdavi, Mohammad
Journal of physical chemistry 2019 v.123 no.7 pp. 4044-4055
air, cobalt, electric field, electrons, nanoparticles, photocatalysis, physical chemistry, solar cells, solar energy, texture, titanium dioxide
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 nanoparticles, 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.