Shifting the NIR into the UV-blue: Up-conversion boosted photocatalysis

Abstract The tangible harvesting of the extensive near-infrared (NIR) range of solar radiation is an ambitious goal to enhance the efficiency for various energy and environmental applications where usually large parts of the solar spectrum are not efficiently utilized, there is plenty of energy at the bottom. In various areas of solar power engineering, in particular in photocatalysis, photon up-conversion (UC) has been attracting growing interest to bridge large band gaps of efficient photocatalysts by shifting NIR photons into UV-VIS ones. Here we highlight recent studies in the field of UC for the photonic activation of photocatalysts. We also present high intense UC UV-blue emissions from K2YbF5:Tm3+ hydrothermal crystals under 980 nm laser excitation for degradation of organic-dyes, proving the role of the UC effect as a clear evidence of spectral shaping of light for photocatalytic environmental purification.