Plasmonic Ag nanowire network embedded in zinc oxide nanoparticles for inverted organic solar cells electrode

• Entirely solution processable electrode/interfacial layer duo.
• Organic solar cell efficiency improvement when ZAZ is used instead of ITO.
• ZnO nanoparticles allow to reduce roughness by filling holes between wires.
• A plasmonic effect of ZAZ electrode is highlighted.
• A thin thickness of interfacial layer allows the plasmon to reach the active layer.

Transparent Electrodes consisting of silver (Ag) nanowires (NWs) and zinc oxide (ZnO) nanoparticles (NPs) were fabricated by spin-coating. Thus, we demonstrated that by embedding AgNWs into the ZnO NPs, we fabricated a transparent multilayer electrode ZnO NPs/AgNWs/ZnO NPs (ZAZ) with a sheet resistance of 13 Ω/sq and an optical transparency of 88%. The optical properties of the ZAZ structure were investigated and calculated using a FDTD method. The modeling results showed a good agreement with the experimental results. Plasmonic behavior is highlighted. The ZAZ multilayer electrodes were experimentally optimized and were successfully integrated into an inverted organic solar cell based on P3HT:PCBM. A photovoltaic efficiency of 3.53% is obtained on the ITO-free organic solar cells (OSC) and is compared to traditional ITO-based devices with an efficiency of 3.16%. Numerical calculations of the intrinsic absorption of the active layer inside an organic solar cell integrating either ZAZ or ITO are performed. Moreover, we explored numerically, the plasmonic effect created by the AgNWs and how it can influence the absorption inside the active layer of solar cells, in order to take advantage of its electromagnetic field increases. We demonstrate that ZAZ electrodes are a promising alternative to conventional ITO films for high performance inverted OSCs due to better transmission and beneficial plasmonic effect.