Study on Photoluminescence Quenching and Photostability Enhancement of MEH-PPV by Reduced Graphene Oxide

In conjugated polymer based photovoltaic devices, efficient charge transfer and photostability of the fluorescence polymer are two essential properties, which could be responsible for better performance and longer lifetime of the device. Hence, it is of great importance to explore strategies that can enhance the exciton separation and improve the photostability of polymers. In this work, composites of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) participated by appropriate amounts of reduced graphene oxide (r-GO), which leads to a significant photoluminescence quenching as well as superior photostability of MEH-PPV, have been investigated. The photoluminescence quenching and photostability of MEH-PPV/r-GO composites have been observed by UV-visible and fluorescence spectroscopy. From transient fluorescence spectrum, the mechanism of photoluminescence quenching has been confirmed to be static quenching, which is caused by electron transfer at the interface of the composite. Furthermore, we propose that this very efficient photoinduced excitation electron transfer from MEH-PPV to r-GO results in protecting MEH-PPV from further chemical degradation reaction. This work shows that graphene is promising as both an electron acceptor and light stabilizer for applications in optoelectronics devices.