Efficient Quantum Cutting of Ultraviolet Solar Radiation by NaGdF4:5% Nanocrystals

NaGdF4:Eu nanocrystals are known to be able to convert UV radiation into the visible range with a quantum yield close to 200% via the quantum cutting mechanism. According to the literature, quantum-cutting luminescence in NaGdF4:Eu nanocrystals is caused by excitation at a wavelength of 202 nm. This way of excitation, however, is not suitable for creating solar light converters due to the absence of this ultraviolet component in the solar spectrum near the Earth’s surface. We have experimentally demonstrated and described the mechanism of conversion by NaGdF4:5% Eu nanocrystals of ultraviolet radiation at a wavelength of 252 nm into visible emission of Eu3+ ions with a quantum efficiency of 188%. These quantum-cutting parameters are of interest for the development of light-converting coatings, for example, in green photovoltaics to improve the efficiency of solar panels.