The Study of the Luminescence of Solid Solutions Based on Yttrium Fluoride Doped with Ytterbium and Europium for Photonics

The majority of the global market for solar photovoltaic devices is based on silicon technology. It is very important to increase their effi ciency through the use of luminescent coatings, including those converting radiation from the UV-blue region of the spectrum into the near-infrared range, where silicon absorbs radiation most effi ciently (Stokes or downconversion luminescence), or from the infrared region of the spectrum in the near-infrared range (up-conversion luminescence). The aim of this research was to synthesize and study the spectral-kinetic characteristics of single-phase solid solutions of Y1–x–yEuxYbyF3 and to determine the quantum yield of down-conversion luminescence. Using the method of high-temperature melting, single-phase samples of solid solutions of Y1–x–yEuxYbyF3 with orthorhombic system were synthesized. For the series of samples with different Eu3+/Yb3+ ratios, upon double doping with these ions, the formation of the corresponding solid solutions with a crystal lattice of the b-YF3 phase was confi rmed. Their chemical composition was determined using the energy dispersion analysis, and it was established that it corresponds to the nominal one. It was shown that both Eu3+ and Yb3+ ions become luminescent upon excitation at wavelengths of 266 nm and 296 nm. This indicates these compounds as promising sensitisers of UV radiation. In this case, upon excitation at a wavelength of 266 nm, luminescence of Eu2+ ions was recorded. The maximum quantum yield values (2.2 %) of the ytterbium downconversion luminescence in the near-infrared wavelength range upon excitation at a wavelength of 266 nm were recorded for YF3:Eu:Yb with the Eu3+:Yb3+ ratios of 0.1:10.0 and 0.05:5.00.