Solar Cells Should be Designed with Infrared in Mind

For solar cells to be useful, they need to be cheap, cover a large area, and be physically flexible, which are benefits of using solution-processed photovoltaics. Much of the current research in solution-processed photovoltaics is dedicated to optimizing solar conversion efficiency in the visible region of the spectrum. However, as Prof. Edward Sargent and co-workers point out in their paper in ACS Nano, half of the sun's power lies in the infrared, and devices should be designed with this in mind.

Sargent and his team report on solution-cast quantum dot photovoltaics that have 3.6% power conversion efficiency in the infrared region. The devices were stable for weeks when stored in a nitrogen environment. The best devices reached external quantum efficiencies of 46% in the infrared and 70% across the visible spectrum. This quality was shown to be reliable and reproducible, with 40 devices produced with similar efficiencies.

The paper “Efficient, Stable Infrared Photovoltaics Based on Solution-Cast Colloidal Quantum Dots” can be seen at http://dx.doi.org/10.1021/nn800093v.