This invention claims a system for increasing the efficiency of hydrogen production through water photolysis in a photo-electrochemical cell by expanding the spectral response range of the catalytic semiconductor, through photoconversion of incident solar radiation towards short wavelengths, using transparent nano-glass ceramic materials composed of a silicon oxide matrix, containing fluoride nanocrystals (PbF2, NaYF4, YF3, KYF4) doped with rare earth ions (Nd3+, Tm3+, Ho3+, Er3+, Yb3+).
System capable of absorbing and harnessing a wide range of energy from the sun in the red and infrared and efficiently converting it, through "upconversion" processes, to the blue and UV range, optimizing the splitting of water into hydrogen and oxygen.