Over 2 Years of Outdoor Operational and Storage Stability of ITO‐Free, Fully Roll‐to‐Roll Fabricated Polymer Solar Cell Modules

Abstract

AbstractWe report on the stability of large‐area (100 cm2), low‐cost, indium‐tin‐oxide (ITO)‐free modules over two years (>17 500 h) under outdoor operational conditions in Denmark and under indoor storage condition by following ISOS‐O‐3 and ISOS‐D‐2 protocols. Irrespective of the testing regimes (storage and outdoor), all modules maintain the maximum power point (MPP) above T80 (the duration over which a solar cell retains above 80 % of its initial MPP) over two years using a simple low‐cost packaging barrier with a water vapor transmission rate (WVTR) of 0.04 g m−2 day−1, an oxygen transmission rate (OTR) of 0.01 cm3 m−2 bar−1 day−1, and a UV cut‐off at 390 nm. Unlike previous studies, localized degradation through edges and contact points in the modules are not overwhelming even after more than two years; therefore, the differences in degradation under long‐term outdoor and storage conditions could be probed. The results suggest that oxygen permeation may be mainly responsible for degradation under outdoor conditions, whereas WVTR has a larger bearing under storage conditions.