Photon Up-Conversion with Lanthanide-Doped Oxide Particles for Solar H2 Generation

Up-conversion (UC) of infrared (IR) photons into visible radiation constitutes a promising strategy to enhance the light harvesting efficiency of photovoltaic and photoelectrochemical devices. In the present study, we integrate Er3+/Yb3+-codoped yttrium oxide (Y2O3) submicrometric particles with outstanding up-conversion properties into mesoporous titanium oxide (TiO2) structures sensitized with cadmium selenide (CdSe) for solar hydrogen generation. We demonstrate that the incorporation of these up-converting particles (UCP) leads to effective H-2 generation with IR photons. Moreover, based on the analysis of the emission lifetimes, we show that the optical interaction between the emitting UCPs and the CdSe absorber occurs via a radiative emission-reabsorption process. The low cost and toxicity and excellent chemical and thermal stability of our UC phosphors allow envisaging them as real candidates for the new generation of long-term photoelectrochemical devices for solar H-2 generation.