A major challenge facing silicon solar cells used in building-integrated concentrator photovoltaics (BICPV) is their reduced electrical response when exposed to light of short or long wavelengths. In an attempt to tackle this problem, single cell static CPV modules were fabricated with some of the devices containing rare earth doped compounds which were dispersed into the system in varying concentrations and geometries. Under a solar simulator at 1000 W/m(2), the power conversion efficiency (PCE) of devices improved up to 11.1% relative through the addition of these materials. At lower irradiances and compared to cells without concentrators, the relative efficiency gains were more pronounced and external quantum efficiency (EQE) measurements suggested spectral conversion was responsible for these enhancements. For a large scale BICPV system, a simple analysis showed cost per watt could fall by up to 8.1% and power output increased from 25.7 to 28.4 W/m(2) through this approach.