Rare-earth doped solid-state phosphor with temperature induced variable chromaticity

Temperature induced variable chromaticity lanthanide multidoped solid-state phosphors are presented. The phosphors are composed of ytterbium-sensitized multiple-doped (Tm, Er, Ho) PbGeO₃-PbF₂-CdF₂ glass excited at 1.064 µm. The temperature induced color variation exploits the heat enhanced effective absorption cross-section of the ytterbium sensitizer under quasi-resonance excitation. The temperature enhancement of the energy-transfer mechanism between the sensitizer and the appropriate active light emitter allows the selective intensity control of the RGB emissions due to distinct excitation routes. The suitable combination of active ions generated variable chromaticity light with CIE-1931 coordinates changing from CIE-X = 0.283; Y = 0.288 at 20 °C to CIE-X = 0.349;Y = 0.412 at 190 °C, and CIE-X = 0.285; Y = 0.361 at 25 °C to CIE-X = 0.367; Y = 0.434 at 180 °C in Yb³⁺/Tm³⁺/Ho³⁺ and Yb³⁺/Tm³⁺/Er³⁺ samples, respectively.