Loughborough University
Leicestershire, UK
LE11 3TU
+44 (0)1509 222222
Loughborough University

Centre for Renewable Energy Systems Technology (CREST)

PV Materials & Devices

Thin Film Cadmium Telluride Photovoltaic Cells

Thin film CdTe is currently the photovoltaic (PV) technology with lowest cost per watt. The technology also offers great scope for further energy cost reductions through increasing the conversion efficiency as well as improvements in module manufacturing techniques. The deployment of the technology is currently limited by lower energy efficiency compared to silicon PV.

Researchers at CREST are working together with researchers at Colorado State University on improving the energy conversion efficiency of CdTe PV and gaining better understanding of the processes involved in the CdTe solar cell fabrication process.

CdTe solar cells currently utilise ~2µm thick CdTe absorbers (diagram of a CdTe thin film solar cell is shown above). If the uniformity of the deposited layers can be improved this thickness could be reduced to 1µm without efficiency loss, offering huge potential for material savings.

Currently industry uses thermal PVD methods for the deposition of the materials utilised in the cell (either Close Space Sublimation (CSS) or Vapour Transport Deposition (VTD)). Sputtering is an alternative PVD deposition method which allows much better uniformity control. Moreover, sputtering allows reduction of the growth temperatures from 500-600ºC used for CSS and VTD to, potentially, as low as room temperature.