Highly transparent Si-doped In2O3 films prepared on PET substrate using roll-to-roll sputtering

We investigated the characteristics of Si-doped In2O3 (ISO) films grown on polyethylene terephthalate (PET) substrates using a lab-scale roll-to-roll (RTR) sputtering system and their ability to function as flexible anodes in flexible organic solar cells (OSCs). Both electrical and optical properties of the flexible ISO films were critically dependent on the direct current power applied to the ISO target. Despite a process temperature lower than 50 °C, we obtained flexible ISO film with a sheet resistance of 144.4 Ω/square and an optical transparency of 81.21% at a wavelength of 550 nm. Due to the amorphous structure of the ISO films, they had a very smooth surface morphology without surface defects and showed good flexibility. Flexible OSCs fabricated on amorphous ISO anodes exhibited a power conversion efficiency of 1.932%. Successful operation of the flexible OSC with an ISO anode indicates that ISO film is a promising amorphous transparent and flexible electrode for flexible OSCs.