We study, by coupled electromagnetic and semiconductor device simulation, the effect of dielectric nanoparticles embedded in the depletion region of thin film solar cells. Absorbed photon densities, calculated using an electromagnetic solver, are mapped to the nodes of an electrical mesh on which three dimensional semiconductor device equations are solved. For the first time, we include here the effects of surface recombination and interface states at the Si/dielectric interface. We predict maximum increases of 9.3% and 9.9% in short circuit current density and efficiency respectively due to enhanced scattering from the dielectric nanoparticles. © 2013 IEEE.