Aging and Degradation of Organic Solar Cells Using QUV Accelerated-Weathering Tester

Abstract

In this paper, we have reported some investigation on the QUV aging of organic solar cells (OSCs). The use of QUV chamber leads to study the effect of cyclic aging on the electrical properties namely PCE, Jsc, FF and Voc under variation of UV irradiation, temperature, humidity and dark. Samples of commercial encapsulated cells supplied by Infinity OPV manufacturer were subjected to 45 cycles (1080 h) of aging. Each cycle of 24 h contains 8 h of illumination with UVA-340 lamp under 50 °C, followed by 4 h of spray (raining) and condensation (humidity generation) at 50 °C, and finished by 12 h of dark. The effect of three different UV irradiation doses (0.83 W/m2, 1.2 W/m2 and 1.3 W/m2) was studied. The degradation process of the OSCs under cyclic aging fits with the earlier finding in the literature and is occurred in two phases with deferent aging rates. The first phase is characterized by the fast decrease of overall electrical properties at the beginning of aging and is due the synergistic effects of rapid variation in the temperature, light and humidity. The second phase is more stable and all the curves reach some saturation. This stabilized phase is the consequence of no bleaching of the semiconductor layer over time. Time constants and constant of degradation were deduced from the first exponential and linear fits of the studied properties. Furthermore, it has been found that the OSCs lose more than 60% of their initial performances, and for some properties like PCE the decrease reaches 80%. This drastic drop of the OSCs performances, associated to the formation of bubbles, indicates that samples undergo very hard bulk degradation.