Polymer Network Modified Mesoporous SnO₂ for Enhanced Fill Factor in Perovskite Solar Cells

The rise of perovskite solar cell performance lies in the increase of fill factor and open-circuit voltage, which depend on high film quality (shunt resistance) and efficient charge transportation (series resistance). Polymer passivation could suppress the film defects, while its poor conductivity leads to a trade-off between passivation quality and series resistance. Here we introduce a polymer network modified mesoporous SnO2 layer to reconcile this contradiction, in which the mesoporous SnO2 was partially coated by the passivation polymer. Electrons can be extracted through the exposed surface of the mesoporous layer, thus realizing high passivation quality and efficient charge transport simultaneously.