Enhancing the performance of silicon solar cells via the application of passive luminescence conversion layers

This paper discusses ways of reducing the two major losses encountered in a single-junction photovoltaic (PV) device—that of sub-band gap transmission and lattice thermalisation losses—via the application of passive luminescent devices called up- and down-converters, respectively. Down-conversion (DC) results in the generation of more than one lower energy photon being generated per incident high-energy photon, while up-conversion (UC) generates one photon with energy for every two or more sub-band gap photons absorbed. A related process of wavelength down-shifting (DS) is similar to DC except that the external quantum efficiency of the DS process is less than unity.