Predicting, categorizing and intercomparing the lifetime of OPVs for different ageing tests

The presented work addresses the issue of lifetime prediction and intercomparison for organic photovoltaic (OPV) devices tested under different environmental conditions according to ISOS guidelines proposed recently at the International Summit on Organic Photovoltaic Stability. The studies employed P3HT:PCBM based devices produced with different architectures and methods ranging from spin coating to roll-to-roll manufacturing. The purpose of the chosen diversity was to establish the possible spread in the ageing rates generated by different architectures. A logarithmic lifetime diagram associated with the common time units was used for presenting the ageing data, which regardless of the spread in the lifetimes allowed categorizing the level of the stability of P3HT:PCBM based devices tested under different ageing conditions. Moreover, the approach also allowed for estimating the acceleration factors between the moderate and harsh ISOS test conditions employed in the study, as well as identifying the level of improvement of the device stability after encapsulation. The effects of different device architectures and encapsulation techniques on ageing rates of the samples were also studied. This report presents the early steps towards establishing a prediction tool for identifying the lifetime of OPV devices under operational conditions based on the tests under harsh (accelerated) conditions. (C)2014 Elsevier B.V. All rights reserved.