Scientific results
3rd Young researchers meet at the IMDEA Nanociencia - Tracing oxygen induced degradation in P3HT : PCBM films: A time domain study
Tracing oxygen induced degradation in P3HT : PCBM films: A time domain study
by Safakath Karuthedath1, Reinhold Wannemacher1, Larry Lüer1
1 Optical Spectroscopy and Microscopy of Nanostructured Materials, IMDEA Nanociencia, C/ Faraday, 9, 28049 Cantoblanco (Madrid), Spain.
Oral Presentation at 3rd Young researchers meet at the IMDEA Nanociencia, Madrid, Spain [June 2013]
Organic solar cells (OSC) consume less energy during production than inorganic solar cells. Further advantages of OSC are transparency, flexibility and colour tunability, making them apt for new markets like, consumer product integration. However, the stability of OSC against photodegradation must substantially be enhanced to enter these markets. In OSC based on poly(3-hexylthio-phene) (P3HT)and[6,6]-phenylC61-butyric acid methyl ester (PCBM),a slight chemical degradation (2% ground state absorption loss) can cause more than 70% reduction in photocurrent generation[1]. In order to reduce degradation-induced performance losses, it is important to understand how the elementary processes of organic photovoltaics are influenced by photodegradation. Here, we present a time-resolved transient absorption study covering the relevant time scale from femtoseconds to milliseconds, comparing samples at different states of photodegradation.
Our results indicate that charge recombination in the P3HT : PCBM OSC is strongly retarded by photodegradation (Fig.1.a), pointing to a substantial reduction of the effective mobility. On the other hand, charge generation is not influenced significantly by weak levels of photodegradation (Fig.1.b).
References
1) F. Deschler, A. De Sio, E. von Hauff, P. Kutka, T. Sauermann, H. -J. Egelhaff, J. Hauch E. Da Camo, Adv.Funct. Matet.2012,22,1461-1469