Self-adhesive macroporous carbon electrodes for efficient and stable perovskite solar cells

Carbon electrode are a low-cost and great potential strategy for stable perovskite solar cells (PSCs). However, the efficiency of carbon-based PSCs lags far behind compared with that of state-of-the-art PSCs. The poor interface contact between the carbon electrode and the underlying layer dominates the performance loss of the reported carbon-based PSCs. In this respect, a sort of self-adhesive macroporous carbon film is developed as counter electrode by a room-temperature solvent-exchange method. Via a simple press transfer technique, the carbon film can form excellent interface contact with the underlying hole transporting layer, remarkably beneficial to interface charge transfer. A power conversion efficiency of up to 19.2% is obtained for mesoporous-structure PSCs, which is the best achieved for carbon-based PSCs. Moreover, the device exhibits greatly improved long-term stability. It retains over 95% of the initial efficiency after 1000 h storage under ambient atmosphere. Furthermore, after aging for 80 h under illumination and maximum power point in nitrogen atmosphere, the carbon-based PSC retains over 94% of its initial performance.