A photovoltaic device including a composite down-converting layer disposed on the device, is presented. The composite down-converting layer includes down-converting material particles dispersed in a matrix. The size of the down-converting material particles is a function of a difference in respective refractive indices (.DELTA.n) of the down-converting material and the matrix such that: (i) for .DELTA.n less than about 0.05, the size of down-converting material particles is in a range from about 0.5 micron to about 10 microns, and (ii) for .DELTA.n at least about 0.05, the size of down-converting material particles is in a range from about 1 nanometer to about 500. A photovoltaic module having a plurality of such photovoltaic devices is also presented.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH & DEVELOPMENT
 This invention was made with Government support under contract number DE-EE0000568 awarded by Department of Energy. The Government has certain rights in the invention.