Ca$_{1-x-y}$Yb$_x$Pr$_y$F$_{2+x+y}$ solid solution powders as a promising materials for crystalline silicon solar energetics

We have synthesized single-phase powders of Ca$_{1-x-y}$Yb$_x$Pr$_y$F$_{2+x+y}$ solid solutions with an average particle size of about 35 nm by coprecipitation from aqueous nitrate solutions. After annealing at 600$^\circ$ C during 1 hour, the particle size was increased up to 150–200 nm. Individual luminescence bands of praseodymium are distinguishable in the luminescence spectrum. The intensity of the luminescence of ytterbium increased by a factor of 1000 in comparison with the unannealed samples. The highest luminescence intensity of ytterbium was detected for the Ca$_{0.9495}$Yb$_{0.0500}$Pr$_{0.0005}$F$_{2.0505}$.