载Ag多孔TiO_2薄膜的制备及其光致变色性能

Preparation of porous titanium dioxide film loaded with Ag particles and its photochromic properties

为了制备具有良好光致变色性能的载 Ag 的 TiO2薄膜，利用 PEG2000和 PEG4000在载 Ag 的 TiO2薄膜中制造出直径在几十纳米以上的密集孔洞，使薄膜呈现出显著的光致变色现象；比较了 PEG 用量、分子量和镀银时间对薄膜光致变色性能的影响。结果表明：无论 PEG 用量增加或分子量增加都会导致薄膜中孔的直径增大，直径50～100 nm 的密集孔洞最有利于提高光致变色速率；孔洞对 Ag 颗粒的尺寸、形状有一定限制作用，但随着孔径的增加，限制作用减弱；Ag 颗粒的尺寸、形状、分布密度更加依赖于镀银时间，决定差分吸收光谱上“烧孔”的形状和位置，过长的镀银时间导致额外的“烧孔”和“烧孔”宽化。

To prepare good photochromic Ag/TiO2 films,polyethylene glycol （PEG）is used to help forming pores in TiO2 films before Ag particles deposition.Results show dense pores with diameter larger than several tens of nanometers successfully form in the films,and the porous films exhibit obvious photochromic phenomenon.Diameter of the pores in the films increases as the amount or relative molecular mass of PEG increases,however,pores with diameter 50-100 nm are most helpful for improving the photochromic speed.Those pores can confine the shape and size of the Ag particles deposited on their surfaces in a certain degree, but the confinement will become weaker as the pores become larger.Shape,size and density of the Ag particles,which determine the positions and shapes of spectral holes burning in the differential absorption spectrum,mostly depend on the time of deposi-tion.Overlong Ag depositing time may induce extra “burning holes”and make the “burning holes”wide.