Enhancing the stability and efficiency of carbon-based perovskite solar cell performance with ZrO 2 -decorated rGO nanosheets in a mesoporous TiO 2 electron-transport layer.

Improving the role of electron-transport layers (ETLs) in carbon-based perovskite solar cells (CPSCs) is a promising method to increase their photovoltaic efficiency. Herein, we employed rGO sheets decorated with ZrO 2 nanoparticles to increase the electron transport capability of mesoporous TiO 2 ETLs. We found that the rGO/ZrO 2 dopant enhanced the conductivity of the ETL, reducing the charge-transfer resistance at the ETL/perovskite interface and reducing charge recombination in the corresponding CPSCs. Notably, this dopant did not effectively change the transparency of ETLs, while increasing the light-harvesting ability of their own top perovskite layer by improving the crystallinity of the perovskite layer. The rGO/ZrO 2 -containing ETLs produced a champion efficiency of 15.21%, while devices with a net ETL recorded a maximum efficiency of 11.88%. In addition, the modified devices showed a higher stability behavior against ambient air than the net devices, which was linked to the passivated grain boundaries of the modified perovskite layers along with the improved hydrophobicity.