Enhanced moisture and thermal stability of transparent electrodes via crosslinking for large-area flexible organic photovoltaic modules†

Abstract

Moisture and thermal stability of flexible transparent electrodes are important for fabricating efficient large-area flexible organic photovoltaic (OPV) modules. Recently, silver nanowires (AgNWs)-embedded polyvinyl alcohol (PVA) was fabricated, possessing excellent optoelectronic properties, mechanical flexibility and surface smoothness for use in efficient large-area flexible OPV modules. However, PVA is vulnerable to moisture and heat, resulting in a narrow processing window for large-area flexible modules. Thus, in this work, we embedded AgNWs into a crosslinked PVA matrix (denoted as AgNWs-em-cPVA), which showed substantially enhanced thermal and moisture thermal stability. Specifically, AgNWs-em-cPVA could withstand a temperature of up to 200 °C, and its moisture adsorption was as low as 1.12% ± 0.19% at a relative humidity (R. H.) of 60% and a temperature of 25 °C for 168 h. The flexible large-area OPV module achieved an efficiency of 14.78% (active area: 52.3 cm²), which is the highest value reported to date for flexible large-area OPV modules on non-ITO electrodes. Furthermore, the flexible large-area OPV modules maintained 92.76% ± 2.50% of their initial efficiencies after continuous AM 1.5 illumination with a UV filter for 1008 hours.