Previously adding carbon nanotubes (CNT) reduces the light emission from the composite, due to quenching of charge carriers at the nanotubes, which are generally metallic in nature for multi-walled CNT. This quenching reduces the emission efficiency of the devices.
This increase in light-emission only occurred when they acid treated the MWCNT prior to inclusion in the polymer. They propose that this increase is due to a novel energy transfer mechanism, from the acid-damaged surface of the MWCNT to the emitting sites in the polymer. In addition to the enhanced light-emission, the study also demonstrates that the MWCNT produced an improvement in the stability of the polymer to light-induced degradation.
Dr. Simon Henley, one of the lead investigators, comments "These results show that carbon nanotubes have enormous potential as a versatile material in future optoelectronic devices, and raise the prospect of utilising MWCNTs to harvest solar radiation in organic solar cells, in addition to improving device stability. "
Professor Ravi Silva, Director of the Advanced Technology Institute states: "The mere fact that now we can have a predictable organic-nanotube hybrid composite, with enhanced properties should open the door for many new applications. The enhancement in the luminescence properties bodes well a new generation of organic devices that could potentially reach commercially viable figures of merit for large scale production.
October 20, 2007
Multi-wall carbon nanotubes increase light emission of polymer 100 fold
Researchers at the Advanced Technology Institute of the University of Surrey, in collaboration with researchers from China and the USA, have demonstrated a 100-fold increase in the light emission from a nylon polymer sample, by incorporating multi-walled carbon nanotubes (MWCNT).