Hydrothermally fabricated TiO2 heterostructure boosts efficiency of MAPbI3 perovskite solar cells

The electron transport layer (ETL) plays an important role in high-efficiency perovskite solar cells (PSCs). TiO2 nanorod (TNR) thin film with outstanding photovoltaic properties is considered as an excellent ETL in the structure of PSCs. To enhance the efficiency of PSCs, ETL heterostructures with anatase TiO2 nanoparticles (TNPs) and rutile TNRs are fabricated and optimized by two-step hydrothermal process. The maximum efficiency of PSCs based on the ETLs of TiO2 heterostructures in this study is 14.143%, which is much higher than that of PSC cell with the ETL of pure TNRs (9.361%). Hypothesis: This study aims to prepare TiO2 heterostructures with two different polymorphic TiO2 (anatase TNPs and rutile TNRs) for high-performance PSCs. Experiments: TiO2 heterostructures are prepared on conductive FTO substrate by two-step hydrothermal process. Commercial TNPs (P25) are used in different heterostructures for comparison. The structural, morphological characteristics and the current-voltage properties of these ETLs are carefully investigated. Findings: The enhanced performance of TiO2 heterostructures-based PSCs is believed to be attributed to the excellent capability of carrier extraction, large surface area, light scattering effect and defect passivation at the ETL/perovskite interface. (c) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.