Cove-Edge Nanoribbon Materials for Efficient Inverted Halide Perovskite Solar Cells

Two cove-edge graphene nanoribbons hPDI2-Pyr-hPDI2 (1) and hPDI3-Pyr-hPDI3 (2) are used as efficient electron-transporting materials (ETMs) in inverted planar perovskite solar cells (PSCs). Devices based on the new graphene nanoribbons exhibit maximum power-conversion efficiencies (PCEs) of 15.6 % and 16.5 % for 1 and 2, respectively, while a maximum PCE of 14.9 % is achieved with devices based on [6,6]-phenyl-C₆₁ -butyric acid methyl ester (PC₆₁ BM). The interfacial effects induced by these new materials are studied using photoluminescence (PL), and we find that 1 and 2 act as efficient electron-extraction materials. Additionally, compared with PC₆₁ BM, these new materials are more hydrophobic and have slightly higher LUMO energy levels, thus providing better device performance and higher device stability.