Graphdiyne: Bridging SnO2 and Perovskite in Planar Solar Cells.

The matching of charge transport layer and photoactive layer is critical in solar energy conversion devices, especially for planar perovskite solar cells based on the SnO2 electron-transfer layer (ETL) owing to its unmatched photogenerated electron and hole extraction rates. Graphdiyne (GDY) with multi-roles has been incorporated to maximize the matching between SnO2 and perovskite regarding electron extraction rate optimization and interface engineering towards both perovskite crystallization process and subsequent photovoltaic service duration. The GDY doped SnO2 layer has fourfold improved electron mobility due to freshly formed C-O σ bond and more facilitated band alignment. The enhanced hydrophobicity inhibits heterogeneous perovskite nucleation, contributing to a high-quality film with diminished grain boundaries and lower defect density. Also, the interfacial passivation of Pb-I anti-site defects has been demonstrated via GDY introduction.