Phosphors, synthesized by the urea homo-precipitation method, were examined as ultraviolet-spectral down conversion materials for improving the light absorption and electrical characteristics of commercial single-junction silicon solar cells. The photovoltaic (PV) cells were coated with erbium and terbium doped gadolinium oxysulfide phosphors encapsulated in ethyl vinyl-acetate binder using blade screen printing technique, and the optimum concentration of phosphor in the composite resulted in the largest light conversion, and superior electrical output and energy transfer efficiency. Moreover, the results demonstrated that the composition of dispersed phosphors has a strong influence on the amount of ultraviolet-light converted and electron transition capacity of PV cells. The experimental results showed in an optimized PV cell, an enhancement of 0.54% (from 12.11% to 12.65%) in the energy conversion of a Si-based PV cell was achieved. Copyright (c) 2015 John Wiley & Sons, Ltd.