UK - Organic based solution processable devices may revolutionise the lighting and photovoltaic industries of the future.
The move away from traditional inorganic materials is driven not only by cost considerations, but also sustainability issues and life-cycle costs. However, current organic device efficiencies and lifetimes are not high enough for many applications.
The lifetime of these devices can be improved by incorporating carbon nanotubes (tubes made of carbon atoms, 1000s of times thinner than the width of a human hair) in the polymer to form a composite.
The addition of the carbon nanotubes typically comes at a cost. For example, in light emitting materials, the presence of the carbon nanotubes (CNT) reduces the 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.
Researchers at the Advanced Technology Institute of the University of Surrey, UK, in collaboration with researchers from China and the USA, have recently demonstrated a 100-fold increase in the light emission from a nylon polymer sample, by incorporating multi-walled carbon nanotubes (MWCNT). This increase in light-emission only occurred when they acid treated the MWCNT prior to inclusion in the polymer. 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.
The researchers say that the 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.
Reference University of Surrey
Source of top image University of Surrey
For more information attend Printed Electronics Europe 2008 and Photovoltaics Beyond Conventional Silicon. Also read Printed and Thin Film Photovoltaics and Batteries and Organic & Printed Electronics Forecasts, Players & Opportunities 2007-2027.