Final Report Summary - NIOS (High Efficiency Nanostructured Electrodes for Organic Solar Cells Using Solution Processed LiF)
Conventional electrode structures for organic electronics often rely on interlayers to enhance the efficiency at inorganic electrodes. In this project, we implemented improved electrodes in organic solar cells by introducing a solution processed LiF interlayer. Compared to state-of-the-art production devices, the new interlayer improves the short circuit current and combined with PEDOT:PSS, leads to higher power conversion efficiencies for P3HT:PCBM devices. By producing nanoparticles with a reverse micelle technique, the solution processing route allows controlled assembly of the LiF dispersion on the surface, resulting in alternative electrodes with a high degree of control over the nanoscale structure. The impact of the nanoparticle dispersions can be described by a lateral depolarisation model, where the dispersion of dipolar islands initially increases the global work function of the surface, but as the island density increases to full coverage, the depolarisation from neighbouring islands leads to a net decrease in the global work function. This allows tuning of the surface work function through the control of the nanoparticle dispersion, necessary for improved performance in devices.