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

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) has been fabricated with excellent optoelectronic properties, mechanical flexibility and surface smoothness for efficient large-area flexible OPV modules. However, the PVA is vulnerable to moisture and heat that cause narrow processing window for large-area flexible modules. In this work, we embed AgNWs into a crosslinked PVA matrix (denoted as AgNWs-em-cPVA) that shows substantially enhanced thermal and moisture thermal stability. The AgNWs-em-cPVA could withstand temperature up to 200 °C and the moisture adsorption is 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 for flexible large-area OPV modules on non-ITO electrodes. The flexible large-area OPV modules maintained 92.76 ± 2.5% of their initial efficiencies after continuous AM1.5 illumination with UV filter for 1,008 hours.