Boosting Efficiency and Stability of Organic Solar Cells Using Ultralow-Cost BiOCl Nanoplates as Hole Transporting Layers

A novel nanomaterial, bismuth oxychloride nanoplates (BiOCl NPs), was first applied in organic solar cells (OSCs) as hole transporting layers (HTLs). It is worth noting that the BiOCl NPs can be facilely synthesized at ∼1/200 of the cost of the commercial PEDOT:PSS and well dissolved in green solvents. Different from the PEDOT:PSS interlayer, the deposition of BiOCl HTL is free of post-treatment at elevated temperature, which reduces device fabrication complexity. To demonstrate the universality of BiOCl in improving photovoltaic performance, OSCs containing various representative active layers were investigated. The power conversion efficiencies (PCEs) of the P3HT:PC61BM, PTB7-Th:PC71BM, and PM6:Y6-based OSCs with the BiOCl HTL boosted from 3.62, 8.78, and 15.63 to 4.24, 9.92, and 16.11%, respectively, compared to the PEDOT:PSS-based ones. It was found that the superior performances of the BiOCl-based OSCs are mainly attributed to the sufficient oxygen vacancies and improved interfacial contact. Moreover, the BiOCl-based OSCs show a much better stability than the cells with the PEDOT:PSS interfacial layer.