CDT’s PLED technology can be used in reverse, to convert light into electricity.  Devices which convert light into electricity are called photovoltaic (PV) devices, and are at the heart of solar cells and light detectors. CDT has an active programme to develop efficient solar cells and light detectors using its polymer semiconductor know-how and experience, and has filed several patents in the area. CDT’s PV technology is based on work developed at the Cavendish Laboratory, part of the University of Cambridge, from which CDT was founded.
Digital clocks powered by CDT's
polymer solar cells



Photovoltaic Devices

Polymer PV cells have an identical structure to polymer displays, and use very similar polymer materials.

The active polymer layer is sandwiched between two conducting electrodes. One of the electrodes is transparent to let the light in or out depending on the application. An additional conducting polymer layer, called PEDOT, is sometimes used to flatten the transport contact and help inject / carry positive charges in or out of the device.

Schematic structure of a polymer PV cell (left) and a PLED display (right)

Light is absorbed in the polymer layers and creates a pair of negative and positive electric charges. We call these electrons and holes. These charges are collected by the electrodes, forming an electric current, which can be used to drive an electronic device.

Schematic cross section through a polymer PV cell, showing absorption of light and generation of an electric current.

The future of polymer solar cells

Polymer solar cells have a huge range of applications, limited only by the imagination.  Low cost, flexible cells could be used in applications where current expensive technologies are uneconomic.  Look out for disposable solar powered displays on packaging in the future.  Mobile phones and laptop computers and the information appliances of the future may all have solar cells top up the batteries, and a flexible solar cell can be integrated into the packaging or case. 

Tents made from large area, flexible solar panels could be used by aid agencies to power vaccine fridges or other vital medical equipment.  Light weight, roll-up power sources would also be ideal for people requiring electricity in remote locations, such as field researchers, mountaineers, sailors and military personnel.

As well as solar cells, polymer PV devices can also be used to make light detectors, with the same advantages of low cost and large area manufacture. This would enable new applications, such as disposable medical image sensors to be made, using sensitive light detection technology in a
portable and cheap package.