Tuning recombination of carriers during radiative conversion with Cuprum and Ferrum co-doping in the photothermal synergy

Abstract

Heat induced by solar irradiation can alter crystal structures and interfacial barriers, which may subsequently impact the generation, transport and recombination of photoinduced carriers during the radiative conversion of semiconductors. However, this factor is often ignored in photoreactions. Thus, this study investigates the influence and mechanism of the thermal effect on radiative conversion in photoreactions. We find that when the temperature increases, 1) the radiative absorbance is broadened, 2) the ability of photoinduced electrons to drive reactions is enhanced, and 3) better mobility of photoinduced carriers is achieved. Interestingly, the radiative recombination of ZnO and In2O3 decreased and increased, respectively during heating, which resulted in increasing and decreasing photocurrents in the corresponding sample. Furthermore, after co-doping In2O3 with Cu and Fe, we reversed the trend of radiative recombination from increasing to decreasing with increasing temperature. Thus, the H2 production increased by 2.53 times at 250 °C relative to that at 150 °C during the photothermal reaction using Cu3/Fe1–In2O3. Finally, we successfully proved that the thermal effect could be converted from a harmful factor into a beneficial role during radiative conversion. This work may inspire more innovative ideas related to the mechanism and utilization of the thermal effect in solar conversion.