Forward and Back Scattering of Luminescent Down-Shifting Particles in EVA Films

Luminescent down-shifting particles can improve solar cell's performance by enhancing the absorption of short-wavelength photons. However, their scattering also leads to the loss of incident light and has negative effects on the performance of the solar cells. In this work, the forward and backward scattering of the luminescent down-shifting particles, which are embedded in ethylene-vinyl acetate (EVA) films, with different diameters and different refractive indices, have been simulated. Simulation results show that larger particles have a higher ratio of the forward scattering energy to the total scattering energy because there is more constructive interference between the forward emissions from the dipoles inside the larger particles. When the refractive index of the particles is close to that of EVA, the forward scattering energy is high, and the backward scattering energy is low. When the refractive index of the particles is far away from that of EVA, the forward scattering becomes weakened, and the backward scattering becomes stronger. These results might be helpful in understanding the influence of down-shifting materials on solar cells.