Boosted humidity resistance of CsPbBr3 perovskite by incorporating 3,4,9,10-perylenetetracarboxylic dianhydride

The surface defects and humidity sensitivity of perovskite have long been challenging issues in optoelectronic devices. Here, we introduced 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) as a dopant into CsPbBr3 perovskite crystals, forming PTCDA-PVSK. By coordinating the carbonyl groups on PTCDA with the under-coordinated Pb2+ ions on the perovskite surface, we successfully addressed surface defects and stability issues under high humidity (RH75%). We measured the surface adhesion of PTCDA-PVSK using the force-distance curve mapping mode of an atomic force microscope (AFM). The results showed a significant 64 % reduction in adhesion variation at grain boundaries of PTCDA-PVSK after long-term exposure to high humidity for four weeks. This indicates that the hydrophobic benzene ring structure of PTCDA acted as a barrier, reducing the sensitivity of perovskite grain boundaries to moisture. Through scanning Kelvin probe microscopy (SKPM) analysis, we observed stable work function of PTCDA-PVSK under high humidity conditions, while the pure PVSK exhibited a 6.2 ± 0.1 % decrease in work function after four weeks. This demonstrates that PTCDA-modified perovskite effectively prevented moisture-induced crystal degradation and enhanced electron transfer efficiency. Overall, this study provides valuable insights for enhancing material performance.