Improvement of the performance of carbon-based perovskite solar cells via interface modification of the double electro transport layer of TiO2/SnO2

The modification of the interface represents a crucial step in the preparation of efficient and stable carbon-based perovskite solar cells(C–PSCs). A multifunctional interfacial material 1-phenylguanidine hydrochloride (PGCl) was introduced between the double electron transport layer of TiO 2 /SnO 2 and perovskite to modify the interface and promote the crystal growth. The Cl - in PGCl can passivate oxygen vacancies and chemically link to ETL through electrostatic coupling , while helping to fix PbI 2 in perovskite. The grain size increase while the surface roughness decreases in the PGCl-modified ETL. The internal electric field attribute to the increase of the open-circuit voltage. The method achieves better energy orientation, fewer interface defects and uniform perovskite crystals, achieving an impressive power conversion efficiency (PCE) of 15.52 %, an open circuit voltage of 0.94 V, and a substantial increase in the fill factor to 77.96 %. The C-PSC based on PGCl modification show 15.4% increase in PCE. More importantly, the initial PCE of the unpackaged device remains at 75.4% after aging for 300 h at 45-50 °C and 60-70% relative humidity . The findings indicate that the incorporation of PGCl represents a promising approach to modifying the perovskite interface and regulating the crystallization of perovskite, with the objective of achieving efficient and stable C–PSCs.