Eu3+-Mn2+-doped bi-functional glasses with solar photon downshifting: Application to CdS/CdTe solar cells

Luminescent downshifting is a viable way for enhancing the short-wavelength spectral-response of photovoltaic device, especially for CdS/CdTe thin-film solar cells. Phosphate glasses codoped with rare earth Mn2+-Eu3+ ions were prepared by high temperature melting method, and the absorption, excitation, and emission spectra of the glasses were investigated in detail. Under the illumination of sunlight (<520 nm excitation), the emission of the glasses can vary from ultraviolet to visible with emitting strong red emission, which just matched the spectral-response of CdS/CdTe cells, result in harvesting short wavelength photons and transferring them into the photocurrent output towards the photoelectric conversion efficiency improvement. In this work, such rare earth ions codoped phosphate glasses are investigated for their potential as bi-functional superstrate glass for CdS/CdTe solar cells and experimental performances of Luminescent downshifting layers fabricated with actual CdS/CdTe cells obtained. As a result, prepared Mn2+-Eu3+ glasses could effectively improve the photoelectric conversion efficiency by 7.140% compared to pure CdS/CdTe solar cells.