Gallium-doped Zinc Oxide with Silver Nanowire Transparent Electrode for Photovoltaic Applications by Atmospheric Pressure Plasma Jet

The importance of transparent conductive oxide (TCO) in optoelectronic applications has long been recognized due to TCO's expensive processes and necessary trade-offs between electrical conductivity and optical transmittance. In our previous works, we successfully coated gallium-doped zinc oxide (GZO) via atmospheric pressure plasma jet (APPJ), a vacuum-free and low substrate temperature process, on bare glass with low sheet resistance (18 Omega/sq) and high transmittance (> 80%) in the visible spectrum. However, the transmittance in the near-infrared regime does not equally behave as the visible spectrum and declines sharply, resulting in a loss of power-conversion efficiency (PCE). Aiming to increase the transmittance in the near-infrared regime while maintaining the conductivity of TCO, we unveiled a novel method by reducing the GZO film thickness and including silver nanowire (AgNW) networks in the coating process. As a result, we achieved a high transmittance (about 80% in the visible spectrum and over 60% in the near-infrared region), even lower sheet resistance (about 10 Omega/sq), and high haze (about 25%) AgNW/GZO film. AgNW networks typically require thermal pretreatment to bond the nanowires and lower the contact resistance. Also, an inactive protective layer is required afterward for its poor stability. With the APPJ procedure, we could bond the AgNWs, and simultaneously cover them with thin GZO shielding film without additional actions. Moreover, our method could adjust the amount of AgNW to balance the transmittance and conductivity. For further investigation, we fabricated AgNW/GZO film into perovskite solar cells to test their performance. The best PCE reached 13.58%, which surpassed 11.23% of the bare GZO film. These results demonstrate that our APPJ system can build a high-quality film with notable transmittance and conductivity in a single step, a cost-effective and time-saving procedure.