Eu2+-Nd3+ co-doped glasses for solar spectrum modification via NUV/visible to NIR downconversion

• Eu 2+ valence state was obtained in sodium silicate glasses. Excitation band was observed 100 nm wider than most materials. • The excitation band overlaps perfectly with the solar spectrum emission in UV–VIS region, providing conversion of the energy in c-Si cell. • Eu 2+ Nd 3+ co-doped glass presented an excellent match between the Nd 3+ emission and the optimal photoconversion energy. The challenge of modifying the solar spectrum intensifies efforts in the pursuit of enhanced materials and optical systems. In this work, we present novel and efficient near infrared-emitting Eu 2+ and Nd 3+ co-doped sodium calcium silicate glasses. Optical absorption, excitation spectra, emission decay time, were measured and discussed as a function of Nd 2 O 3 content. Laser power-dependent emission intensity was used to evaluate the transfer mechanism, and an energy level diagram was proposed. For the sample doped with optimized neodymium content, energy transfer efficiency reached 70%. For co-doped samples, the excitation spectrum was broadly intense and perfectly overlapped with the solar spectrum in the NUV region. Therefore, NUV/Visible can be efficiently converted into NIR, precisely where the C-Si response is maximal, through the Eu 2+ →Nd 3+ pathway. This work’s outcomes made the focused materials worthy for solar cell applications, optimizing energy conversion lost by thermalization, into useful energy.