Red-green-blue upconversion luminescence and energy transfer in Yb3+/Er3+/Tm3+ doped YP5O14 ultraphosphates

Despite the presence of large phonons energy due to the phosphate material, around 1200 cm−1, Er3+ and Tm3+ visible emissions due to up conversion phenomena can be subsequently combined in order to obtain a white light and find new applications in display devices.