Fiber laser annealing of brush-painted ITO nanoparticles for use as transparent anode for organic solar cells

We report on a fiber laser annealing process for brush-painted ITO nanoparticles, for use as transparent anodes in cost-efficient printable organic solar cells (OSCs). By simple brushing of ITO nanoparticle ink onto glass substrates followed by direct fiber laser annealing, we fabricated solution-processed ITO anodes with a sheet resistance of 56.79 Ω/square and an optical transmittance of 85.77%. The electrical, optical, and structural properties of ITO nanoparticle electrodes were investigated as a function of laser scan speed under a nitrogen ambient. In addition, the detailed microstructure of the laser-annealed ITO electrode was examined to explain the conduction mechanism. OSCs fabricated on laser-annealed ITO electrodes exhibit an open circuit voltage of 0.59 V, short circuit current of 9.02 mA/cm², fill factor of 53.30%, and power conversion efficiency of 2.81%. Successful operation of those OSCs with laser-annealed ITO electrode indicates that fiber laser annealing is a simple and cost-effective option to replace conventional energy-intensive furnace-based annealing processes.