Iron oxide-based charge transport layers for efficient and stable perovskite solar cells

Abstract Perovskite solar cells (PSCs) represent the future generation of photovoltaic technology, offering power conversion efficiencies (PCEs) comparable to the best silicon solar cells. This research primarily investigates the effect of charge transport layers (CTLs) on the performance and stability of PSCs, focusing on their interfaces with the perovskite layer. Among the various CTLs, iron oxides, particularly hematite ( α -Fe 2 O 3 ) and magnetite (Fe 3 O 4 ) have shown significant potential due to their cost-effectiveness, stability, and non-toxicity. This study explores the use of α -Fe 2 O 3 as the electron transport layer (ETL) and a bilayer of magnetite (Fe 3 O 4 ) and spiro-OMeTAD as the hole transport layer (HTL). The incorporation of these iron oxides significantly enhances the optical and morphological properties of PSCs, achieving an impressive PCE of 18.63%, with a J SC of 22.34 mA.cm −2 , V OC of 1.14 V, and FF of 73.36%. These enhancements are attributed to improved thin film morphology, efficient charge collection, and reduced recombination losses. α -Fe 2 O 3 enhances electron mobility and reduces optical losses as the ETL, while Fe 3 O 4 in the HTL minimizes recombination and improves interfacial contact. Together, they significantly boost device efficiency and stability. This research presents a viable approach to achieving efficient and stable PSCs by utilizing iron oxides as CTLs.