Flexible and transparent IWO films prepared by plasma arc ion plating for flexible perovskite solar cells

We investigated flexible W-doped In₂O₃ (IWO) electrodes prepared by arc plasma ion plating (APIP) as a substitute for sputtered amorphous ITO electrodes in flexible perovskite solar cells (FPSCs). In spite of the room temperature ion plating process, the APIP-grown IWO film showed a low sheet resistance of 37.14 Ohm/square, a high optical transmittance of 96.0%, high near IR transmittance, and a small bending radius of 5 mm. In addition, the IWO film shows an atomically smooth surface with a root mean square roughness of 0.83 nm due to the absence of the resputtering effect during the ion plating process. The FPSC with the ion-plated IWO electrode showed comparable performances to a commercial amorphous ITO electrode in an FPSC with an open circuit voltage (0.837 V), short circuit current (18.67 mA/cm²), fill factor (72.54%), and power conversion efficiency (11.33%). Moreover, the microstructure and interfacial structure of the APIP-grown IWO film employed in a FPSC were examined by high-resolution transmission electron microscopy and the sheet resistance of the IWO films was correlated to the FPSC performance.