A. Shalav, B. S. Richards, T. Trupke, R. P. Corkish, K. W. Krämer, H. U. Güdel and M. A. Green
The Application of Up-Converting Phosphors for Increased Solar Cell Conversion Efficiencies
Proc. 3^rd World Conf. Photovoltaic Energy Conversion, Osaka, May 12-16, 2003, p. 248-250                 

Abstract: Up-conversion (UC) is the generation of one higher energy visible/near infrared (NIR) photon for two or more lower energy (NIR) photons. Most commercial applications for UC materials require the emission of visible light. However, a silicon solar cell is able to absorb NIR radiation and is not constrained to just visible light. Erbium-doped fluoride-based UC phosphors with known visible and NIR emission were attached to the rear of a bi-facial silicon solar cell. The external quantum efficiency (EQE) of solar cell system is reported and compared with the absorption properties of the phosphors.