Fully solution processed semi-transparent perovskite solar cells with spray-coated silver nanowires/ZnO composite top electrode

Semi-transparent perovskite solar cells with spray coated silver nanowire (AgNW) and AgNW/ZnO composite top electrode were fabricated and investigated. For the spray coated AgNW electrode, both sheet resistance (Rs) and averaged visible light transmittance over 400–800 nm (AVT) decrease with the decrease of nozzle moving speed, which is ascribed to the increase of AgNW density of the electrode. A highest power conversion efficiency (PCE) of 13.27% with a low AVT of 16.3% was achieved for a small area cell having AgNW top electrode with Rs of 15 Ω/□. A thin layer of ZnO nano particles was coated onto the AgNW electrode, which decreases the sheet resistance of the AgNW/ZnO composite electrode. Such a conductivity enhancement is ascribed to the improvement the interconnection between AgNWs by filling the voids between AgNW wires with ZnO nanoparticles. In the meanwhile, owing to the light scattering effect of ZnO nano particles, light transparence in the visible light range (400–800 nm) of the AgNW/ZnO composite electrode increases slightly after the deposition of ZnO layer. Both device performance and reproducibility of the perovskite solar cells are improved by using the AgNW/ZnO top electrode. As an example, power conversion efficiency of 7.30% with an AVT of 23.3% was achieved for a small solar cell using AgNW electrode with Rs of 78 Ω/□. While a highest PCE of 11.13% with the same AVT was achieved for the same cell after the deposition of ZnO layer, demonstrating the cover effect of ZnO layer. A high PCE of 8.18% was also achieved for a AgNW/ZnO based cell with an area of 1 cm2, which is more than 50% enhancement than the AgNW based cell (5.35%). [Display omitted] •High performance perovskite solar cells with spray coated electrode were fabricated.•A thin PEI layer was used to improve the connection between PCBM and AgNW.•Improved conductivity of the AgNW electrode by coating a ZnO top layer.•Higher device performance was also found for the AgNW/ZnO based cells.