Enhanced Efficiency of Functional Smart Window withSolar Wavelength Conversion Phosphor–Photochromic Hybrid Film

摘要

Here, the high sensitivity and enhanced photochromic efficiency of the hybrid film of solar wavelength conversion phosphor and photochromic film for functional smart window have been achieved by fabricating a double-layered hybrid structure of wavelength conversion phosphor and photochromic film. Y2SiO5:Pr³⁺ phosphor nanoparticles, which upconvert visible light to UV light, were synthesized by simple hydrothermal method. The synthesized Y2SiO5:Pr³⁺ nanoparticle was coated as layered structured film on photochromic H3PW12O40 film. The Y2SiO5:Pr³⁺/H3PW12O40 hybrid film showed an enhanced sensitivity and efficiency of photochromic process with solar light irradiation due to the increased UV portion of solar light through upconversion process of visible light by wavelength conversion phosphor layer. The increased UV portion by upconversion process of Y2SiO5:Pr³⁺ layer through excited-state absorption and energy transfer upconversion process, contributed to an enhancement of coloration rate of photochromic H3PW12O₄₀ film by 7 times with 50 min of 1 sun irradiation due to fast conversion of W⁶⁺ state to W⁵⁺ state in H₃PW₁₂O₄₀ film with 5 times enhanced photochromic sensitivity compared with pristine photochromic film.