High performance carbon-based planar perovskite solar cells by hot-pressing approach

A simple yet effective method based on hot-pressing a free-standing carbon film onto adjacent hole transport layer (HTL) is used to fabricate carbon electrode for planar perovskite solar cells (C–PSCs). Due to the thermoplasticity of as-prepared carbon film, the conductivity of the carbon electrode is enhanced by over ten-fold and the adhesion to adjacent layer is dramatically strengthened via this hot-pressing process. By optimizing the pressing temperature, 15.3% of power conversion efficiency (PCE) is obtained for CuSCN based C–PSCs, which is 70% high than the device without heating at the same pressing pressure. The device demonstrates 93% performance retention after being stored in a humid environment (55–70%) without encapsulation over 80 days. This facile fabrication process of PSCs paves a way to facilitate commercialization of the new PV technology.