Transparent Conductive Oxide Electrodes in Perovskite Solar Cells: Challenges, Strategies, and Outlook

In perovskite solar cells (PSCs), transparent conductive oxide (TCO) electrodes, such as fluorine-doped tin oxide (FTO) and indium tin oxide (ITO), serve as critical components for optical windows, charge collection, and transport. The intrinsic properties of TCOs and their interfacial compatibility with adjacent functional layers significantly affect the device efficiency and stability. This review systematically summarizes the prevalent challenges associated with TCO electrodes, including inadequate light transmittance and electrical conductivity, limited interfacial compatibility, and inherent brittleness. The underlying mechanisms affecting device performance and corresponding engineering strategies are elaborated. Light transmittance and electrical conductivity are enhanced via elemental doping, process optimization, surface texturing, and antireflective coatings. Interfacial compatibility is improved through optimizing deposition techniques, interface engineering, and intrinsic property tailoring of TCOs. The mechanical reliability of TCO-based flexible devices is reinforced by constructing flexible composite structures and stress compensation interfaces. Finally, this review provides insights for further investigation and development of TCO electrodes in PSCs, aiming to advance the commercialization of PSCs.