Hybrid Organic/Silicon Solar Cells Using Solution-Processed Aluminum-Doped Zinc Oxides as Efficient Electron Selective Contact

Recently, hybrid organic silicon heterojunction solar cells have attracted significant interests due to good device performance and simple solution processes. However, electron transport across the cathode interface remains one of the critical issues to be solved. In this study, we employ aluminum-doped zinc oxide (AZO) nanoparticle dispersion to form an electron transport interlayer between the n-type silicon (n-Si) and rear-side aluminum (Al) electrode via blade coating. We further investigate the correlation between the surface morphology and the device characteristics for various furnace annealing conditions: 200°C, 300°C, and 350°C. The hybrid solar cell with the AZO interlayer annealed at 300°C exhibits the highest power conversion efficiency (PCE) of 11.8% with a fill-factor (FF) of 71.3%, where the film morphology shows small and relatively smooth grains revealed by the atomic force microscopy. As a comparison, the reference counterpart without the AZO interlayer exhibits a PCE of 8.5% with a FF of 61.7%. The preliminary results demonstrate the potential of inorganic nanoparticle solution processes for forming a uniform and homogeneous interlayer. Further work on the contact resistance and carrier selectivity of the AZO thin film is still in progress and will be presented.