Potential for quantum dots (QD), nano-sized semiconductors, for producing solar cells with higher power conversion efficiencies has been shown by researchers in Europe and Canada.
Researchers at Delft University of Technology in the Netherlands have proven photoexcited electrons can move freely in layers of separate QDs clustered very closely. The arrangement allows for every light particle absorbed by the solar cell to result in the generation of mobile electrons and holes.
It has been possible to produce photoexcited electron-hole pairs inside QDs, but the breakthrough by Delft enables the electrical current generated to be collected by the solar cell's electrode.
Solar cells fabricated using QD materials can achieve efficiencies of 44% and even 60% - more than double that of high efficiency crystalline silicon photovoltaic (PV) modules available today.
The University of Toronto, Canada, and King Abdullah University of Science and Technology, Saudi Arabia will also jointly commercialise a new QD solar cell breakthrough, developed by Toronto researchers. The research team has been able to link up QDs more closely together, removing the need for organic materials that surround the dots.
The research enables QD materials to be processed as coatings and inks, without organic molecule spacers. Most importantly these densely packed colloidal QD PV structures have exhibited higher power conversion efficiencies.
Both research projects have the potential to lead to higher efficiency and more cost-effective solar cells. QDs can be made as films and inks, and fabricated as very thin material layers in solar cell structures, on high volume processing equipment.
QD production
Several commercial QD materials and technology companies are focused on scaling up the production of high-performance QDs for photonics applications like solar cells, displays and solid-state lighting.
UK-based Nanoco Technologies is one of the most advanced in terms of ramping up production of its QDs. The company expects first consumer electronics products exploiting its nanomaterials to launch by the end of 2011.
The first is likely to be a flat-screen television, where Nanoco's QDs are used as part of the display's backlight.
The firm has recently signed an additional agreement with electronics equipment supplier Tokyo Electron as part of a solar cell project outlining the next phase of an ongoing collaboration with the Japanese partner, which started in June 2010.
The second phase will take until the second half of 2012 to complete and will focus on further improving the performance of a solar film developed using a solar ink made with Nanoco's nanoparticles. The ink can be printed using processes developed by Tokyo Electron to create an efficient, low-cost solar cell.
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Nanoco
The UK quantum dot producer, is working with a series of partners in displays and photovoltaics
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Organic solar firm launches pay-as-you-go energy system in Africa
Cambridge-headquartered Eight19 is launching a portable energy harvesting system in Africa and India, to provide pay-as-you-go solar electricity
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Nano solar developer secures funding to commercialise technology
A Norwegian company developing a new thin-film solar cell has begun a programme to develop a prototype by 2013, with the aim of commercialisation by 2015 at the earliest
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