Plastic solar cells project gets £5m government funding
Wednesday 17 October 2007
“Within three years we are looking to be able to make devices that last of five years and they will have five per cent efficiency,” TTP’s Guy Newcombe told EW. “Then we will build a pilot line.”
The University’s Cavendish Laboratory will be providing materials technology – it recently made cells from polythyophene and polyfluorene for example – but “the project is focussed on learning about the processes for making solar cells over large areas”, said Dr Neil Greenham of the Cavendish.
Both Cambridge and TTP have printing expertise, and TTP has experience in forming businesses to exploit technology.
“The project output is a technological device with will lead to a commercial roll-out,” said Newcombe.
Organic semiconductor devices are notoriously difficult to keep working when exposed to the elements. “How you are in reality going to hit lifetime and efficiency is to have really good control over your production process,” said Newcombe.
Ultimately reel to reel production on plastic substrates is the aim of the programme, “using the minimum amount of material per square metre”, said Newcombe.
In a plastic solar cell, two different polymers are required to separate the photon-induced electron-hole excitons.
“The excitons are strongly-bound on the same molecule. You need a chemical interface to pull the carriers apart,” said Greenham.
A large area of interface is needed between the two materials, with good pathways between the interface and the cell electrode through which to extract the carriers.
“The challenge is to control the nanostructure during fabrication,” said Greenham. “Polymers like to separate, and by controlling how much time you allow them to do this, you can get some rather nice nanostructures.”
The Carbon Trust is aiming high: “If the project succeeds in its aim to deploy more than 1GW of the solar panels by 2017. It could deliver CO[sub2] savings of more than 1 million tonnes/year.”
See also: the Electronics Weekly focus on solar cells, presenting a roundup of content related to photovoltaic technologies, converting light sources to energy.