Luminescence and stability of CaS: Eu2+, Sm3+ down/up conversion phosphor and film

CaS: Eu2+, Sm3+ is a type of down and up double model conversion phosphor, which can transfer infrared and violet-blue light to red light and is supposed to be light conversion agent used for agricultural film. In view of this, CaS: Eu2+, Sm3+ phosphor was synthesized by high temperature solid-phase method and then was applied to the fabrication of the spectrum conversion film (SCF). The emission peak of CaS: Eu2+, Sm3+ phosphor is 635 nm corresponding to the 4 f65d1→4 f7(8S7/2) transition of Eu2+ ions, and the excitation peaks are located at 278 and 467 nm, respectively. Simultaneously, the phosphor also can convert 800–1600 nm infrared light into visible light. While using temperature is lower to 210 °C, the luminescence intensity decrease of phosphor is less than 16%. The SCF has high transparency at visible region more than 70% and high absorption properties at ultraviolet (UV) region and blue. And that the SCF has also the down and up double model conversion properties, the luminescent intensity of the SCF increases with the increase of the doping concentration of phosphor. The SCF shows good stabilization, the photo-aging of SCF is only 19% after a strong UV light continuously illuminating 20 days.