Efficient perovskite solar cells based on polyoxyethylene bis(amine) and NaPF6 modified SnO2 layer with high open-circuit voltage

The electron transport layer (ETL) of SnO with a rough surface, low conductivity, and poor wettability has limited its application in perovskite solar cells (PSCs). To address this issue, we propose a strategy that involves the simultaneous use of bulk dopant NaPF and polymer stabilizer NH-PEG-NH in SnO. NH-PEG-NH is compatible with both SnO and NaPF, resulting in a homogeneous distribution. Additionally, the intrinsic hydrophilicity of the polymer facilitates the formation of a continuous and ordered ETL with improved wettability. The inclusion of NaPF as a bulk dopant enhances conductivity and promotes upper perovskite growth. As a result, optimized morphology, aligned energy levels, improved crystallinity, and reduced bottom defects are achieved in the fabricated perovskite layer. The champion device exhibits a power conversion efficiency (PCE) of ∼23.36%, which is ∼11.88% higher than that of the pristine device (PCE = 20.88%). Notably, the reaches ∼1.2 V with only ∼0.08 V of loss, which is among the highest report one. Furthermore, the PCE of the modified unpackaged PSC was only attenuated by 25% after 250 h of maximum power point tracking in the environment. These results present an alternative and effective approach for preparing high-quality SnO ETL for efficient PSCs.