Bathocuproine, an Old Dog New Tricks for Boosting the Performance of Perovskite Solar Cells

Perovskite solar cells (PSCs) have demonstrated extensive prospects for future applications. However, defects remain as the crucial factor that impedes their further advancement in performance, and passivation of the interfaces (such as the buried and/or top interfaces) is regarded as one of the most effective approaches. Herein, we aim to address another important interface, namely, the indium tin oxide/electron transport layer (ITO/ETL) interface in n-i-p structured devices. Since electron transport layers are typically fabricated using commercial nano tin dioxide, which often display insufficient density. To combat this, we employ the most commonly used bathocuproine (BCP) material to treat the ITO/ETL interface. The incorporation of BCP diminishes the direct contact between the perovskite and ITO layers, while also passivating buried interface and adjusting the crystal orientation of perovskites. Furthermore, the substrate layer exhibits improved transparency, consequently elevating the utilization rate of light by perovskite. As a result, the BCP-based PSC exhibits an impressive efficiency greater than 22%, surpassing the control one of 19.91%, and which simultaneously demonstrates excellent stability. Notably, the optimization of this interface has universal applicability in the improvement of PSCs performance.