Fully indium-free flexible Ag nanowires/ZnO:F composite transparent conductive electrodes with high haze

Abstract

Solution-processed metal nanowires (NWs) and Earth-abundant doped ZnO have been proposed to replace the most widely used indium tin oxide (ITO) transparent and conductive electrode. Generally, there is a dilemma, the trade-off between optical transparency and conductivity for these materials taken alone makes them difficult to compete with commercial ITO. In this work, a modified polyol synthesis method was adopted to grow single-crystal silver nanowire with controlled length by adding AgNO₃ solution in advance and using high molecular weight polyvinylpyrrolidone (PVP). Ag nanowires ink was then spin coated onto flexible PET substrate to form Ag NW mesh, which shows impressive transparent and conductive (TC) property with sheet resistance of 23 Ω sq⁻¹ and transmittance of 90.4% at a wavelength of 550 nm. A post fluorine-doped ZnO (FZO) layer was then deposited by pulsed laser deposition method to improve the TC, stability and mechanical property. High-quality Ag NW/FZO composite electrode was finally acquired at room temperature after optimizing the Ag NW length, concentration in suspension, and FZO layer thickness, with transmittance of 83% at wavelength of 550 nm, sheet resistance of 17 Ω sq⁻¹, and high haze of 36.5%. Perovskite solar cells incorporating such Ag NW/FZO composite electrode exhibited a better cell performance compared to the similar FTO-based perovskite solar cells.