Organic solar cells fabricated on inkjet-printed indium tin oxide electrodes

We fabricated organic solar cells (OSCs) with different active areas on inkjet-printed indium tin oxide (ITO) films and investigated the effect of active area on the performance of the OSCs. By inkjet printing of ITO nanoparticles and rapid thermal annealing in a N2/O2 ambient at 450 °C, we were able to obtain directly patterned ITO electrodes with an average transmittance of 81.9% at 400–600 nm wavelengths and a sheet resistance of 198.8 Ω/square without using a conventional photolithography process. The power conversion efficiency (PCE) of the OSCs fabricated on identical inkjet-printed ITO decreased with increasing active area due to a decrease in fill factors of the OSCs. Based on current density–voltage curves of the OSCs, we suggest a relationship between PCE and series resistance of inkjet-printed ITO films.