Enhancing the perovskite solar cell performance by the interface modification of Zn-Sn-O compound heterostructures

Enhancing the performance of perovskite solar cells (PSCs) is one of the prime concerns of researchers worldwide. For PSC devices, it is essential to develop the individual layer efficiently and cost-effectively. This work emphasizes the possibility of employing Zn-Sn oxide-based composite materials as alternative electron transport layers (ETLs) in PSC devices. Pristine Zn₂SnO₄ (ZTO), composite ZTO-ZnO, and ZTO-SnO₂ heterostructure-based ETLs were prepared by a simple solid-state calcination technique and proposed as an alternative to the TiO₂ photoanode used in PSC devices. The power conversion efficiency of the designed PSCs was studied based on crystallinity, morphology, cross-section, roughness, contact angle, work function, and Raman analysis of the ETL material. TEM analysis confirms the phase pure ZTO and heterostructure formation as a function of material stoichiometry. Compared to the pristine ZTO, the ZTO-ZnO and ZTO-SnO₂ composites have enhanced PSC performance. The ZTO-SnO₂ composites exhibit better band matching and charge transfer behavior with the perovskite layer than the pristine ZTO and ZTO-ZnO composites. The ZTO-SnO₂ ETL-based PSC device displays a maximum efficiency of 15.9%, while ZTO-ZnO shows a maximum efficiency of 14.3%, which is more than 12.6% for the pristine ZTO. The results indicate that Zn₂SnO₄-based composites can be suitable for ETLs in PSC device fabrication.