Recent Progress in Fe₂O₃–Graphene/TiO₂ Nanocomposite Photoanodes for Dye-Sensitized Solar Cells

Abstract

Dye-sensitized solar cells (DSSCs) remain a promising third-generation photovoltaic technology because of their low production cost, mechanical flexibility and good low-light performance. However, the efficiency of conventional TiO₂ photoanodes is limited by the wide band gap (≈3.2 eV), low electron mobility and charge trapping. Ternary nanocomposites combining TiO₂ with graphene derivatives, which improve electron transport, and Fe₂O₃ (2.0–2.2 eV), which extends visible-light absorption and aids charge separation, have therefore been proposed. This narrative review summarizes progress in the design and synthesis of Fe₂O₃-graphene/TiO₂ photoanodes for DSSCs, based mainly on literature published between 2020 and 2026. Hydrothermal, solvothermal, sol-gel, microwave-assisted, electrospinning and sonication routes are compared for scalability, structural control and component distribution, and characterization methods are related to structure-property-performance relationships. Key mechanisms, optimal loading and interfacial interactions are discussed. Direct photovoltaic evidence from fully integrated ternary photoanodes is very limited, and most quantitative data come from binary Fe₂O₃/TiO₂ or graphene/TiO₂ systems. The ternary architecture should therefore be regarded as a scientifically motivated hypothesis, based on complementary binary evidence that must be tested systematically under standard DSSC fabrication and testing conditions. Composition optimization, interface control, scalable synthesis and durability assessment are the main research priorities.