Reducing reflection of down-shifting solar cells through scattering by particles

The improvement of down-shifting solar cells through reducing the reflection in short wavelength range by scattering is investigated experimentally and theoretically. Such down-shifting solar cells are fabricated by doping Y2O3 particles into down-shifting ethylene vinyl acetate films with CaAlSiN3:Eu2+ phosphors. Experimental results show that the scattering of Y2O3 particles can reduce the reflection of the down-shifting solar cells in the wavelength below 450 nm. It can be attributed to two reasons. The first is that the backscattering in the short wavelength is weaker than that in the middle and long wavelength. The second is that the scattering by Y2O3 particles allows more light reach the phosphors and increases their absorption. This means that more photons with poor spectral responses can be converted into the photons with better spectral responses. This work provides a way to realize simultaneously strengthening the down-shifting effect and suppressing the phosphor-induced reflection and can be used to further improve the down-shifting solar cells.