Broad range energy absorption enabled by hydrogenated TiO2 nanosheets: from optical to infrared and microwave

Abstract

Efficient energy harvesting is critical in developing various future clean energy sources and technologies from our ultimate clean energy source – the Sun, which covers a broad range of photon energies ranging from ultraviolet, to visible, infrared, and microwave regions. Absorption is the first key step in the uptake of solar energy for various energy conversions and utilizations. Materials with broad-range electromagnetic interaction are therefore highly desirable. Here, we demonstrate that such broad-range energy absorption from visible light to microwave regions can be achieved with hydrogenated TiO₂ nanosheets. A large near-infrared and visible-light absorption (>60%), a broad mid-IR absorption, and a highly efficient absorption in the microwave region have been obtained with hydrogenated TiO₂ nanosheets. In contrast, barely any absorption is observed for pristine TiO₂ nanosheets in these regions. Therefore, this study shows that with such high absorption across such a broad energy range, hydrogenated TiO₂ nanosheets obviously have a large capability of absorbing solar energy across a broad energy region, which can be potentially useful for various photo, photoelectric, photochemical applications, such as semiconductor devices, photocatalysis, photovoltaics, infrared detection, microwave communication, etc.