Copper Contact for Perovskite Solar Cells: Properties, Interfaces, and Scalable Integration

Copper (Cu) electrodes are increasingly considered practical, sustainable alternatives to noble‐metal contacts in perovskite solar cells (PSCs). Their appeal derives from earth abundance, low resistivity, mechanical ductility, and compatibility with scalable fabrication. At the same time, Cu's redox activity, susceptibility to oxidation, and propensity for interfacial diffusion and halide reactions can undermine device stability and efficiency. This review critically surveys the integration of Cu electrodes across PSC architectures, emphasizing deposition and patterning methods, interfacial and barrier‐layer engineering, and encapsulation strategies. This study synthesizes mechanistic insights into degradation pathways—including Cu oxidation, formation of Cu halides/oxides, ion migration, and contact‐selectivity losses—and evaluates mitigation approaches such as diffusion‐blocking interlayers, alloying, and energy‐level tuning. Comparative analysis versus Au and Ag highlights techno‐economic and reliability trade‐offs relevant to scale‐up. This study concludes with an outlook on co‐designing materials, interfaces, and processes to enable durable, high‐efficiency, and manufacturable PSC employing Cu contacts.