A low-temperature carbon electrode with good perovskite compatibility and high flexibility in carbon based perovskite solar cellsElectronic supplementary information (ESI) available: Experimental procedures, device fabrication details and characterization. See DOI: 10.1039/c8cc09905g

A low-temperature carbon electrode with good perovskite compatibility is employed in hole-transport-material free perovskite solar cells, and a champion power conversion efficiency (PCE) of 11.7% is obtained. The PCE is enhanced to 14.55% by an interface modification of PEDOT:PSS. The application of this carbon on ITO/PEN substrates is also demonstrated. A low-temperature carbon electrode with good perovskite compatibility is employed in hole-transport-material free perovskite solar cells, and a champion power conversion efficiency (PCE) of 11.7% is obtained.