Berlin 2015 – wissenschaftliches Programm
TT 60.12: Vortrag
Mittwoch, 18. März 2015, 12:30–12:45, C 130
Influence of post-production thermal stress on organic photovoltaic cells — •Arne Hendel, Marlis Ortel, and Veit Wagner — Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
One of the mayor challenges of organic photovoltaic cells towards large scale industrial production is the lifetime of the organic solar cells. Accelerated lifetime tests can be performed by applying thermal stress to the devices. In this study, PTB7:PCBM bulk hetero-junction solar cells were exposed in a post-production thermal heat step to temperatures up to 140°C. The reaction to thermal stress was investigated by impedance analysis and light intensity dependent I-V characteristics. It was found that the overall conductivity improved by thermal stress. In addition, an asymmetric series resistance which depends strongly on the light intensity was found by the light intensity dependent measurements. Furthermore, an investigation of the diode characteristic in dark revealed a deterioration of the blocking behaviour for reverse voltages. The results of the impedance analysis and light intensity dependent measurements were compared to AM1.5G I-V characterization, which was used to monitor the degradation of the device performance. A physical device model including the contact properties of the solar cells is presented to explain the findings.