Self‐Encapsulable Carbon Electrode for Efficient and Stable Perovskite Solar Cells

Since the perovskite solar cell (PSC) is emerging as a next‐generation photovoltaic, the counter electrode takes a significant role in the commercializing process. Not only the nature abundancy of carbon, but also the proper electronic property and flexibility allow the carbon electrode as a strong candidate for the future electrode. Herein, heat, moisture, and light‐resistive electrode‐based PSCs are fabricated via tailored elastomer and carbon materials. For device applicable perspective and to fabricate encapsulative electrode, carbon paper and paste obtaining elastomer‐based binder (polyisobutylene) are utilized together; both J–V performance up to 17% and long‐term stability are enhanced compared to the single‐paste system. To confirm the hydrophobicity with encapsulating ability, a direct water‐dipping test is conducted and negligible power conversion efficiency (PCE) loss is observed. Last but not least, the optimized device without extra encapsulation exhibits robust stability under harsh conditions retaining ≈80% of initial PCE for 750 h (60 °C and 1 sun), which paves the new concept of carbon electrode as an electrode itself and encapsulating material at the same time.