Preparation And Characterization Of Electrochromic Tio₂ Thin Films Dipped By Ce/sm

Due to a variety of outstanding characteristics, such as continuously adjustable electric properties, polychrome display, low performance voltage, low energy consuming, radiationlessness, and big look angle, electrochromic thin films have a promising application future. Especially, TiO2 is the best candidate material for iron storage layer in the electrochromic components, in virtue of the compatativly weak electrochromic on the negative electrod.In our work, pure electrochromic TiO2 thin films, as well as that dipped by Ce/Sm, was prepared via sol-gel method. The dipping of Ce/Sm was achieved by adding correspondent nitrates during the preparation of sol-gel, with a dipping molar-consistency of 2%,5%,10%,15% and 20% respectively. TiO2 thin films were coated on the conductive glass (ITO) by means of dip-withdraw method using the self-assembly coating machine. Finally, a homogenous and transparent one was obtained by the following heat treatmentTiO2 powder and thin films were characterized by XRD,TG-DTA,FT-IR,SEM and the elctrochromic properties of the films were analyzed by Electrochemical Workshop. Our investigations just concentrated on the influence factors of electrochromic properties of TiO2 films, as well as the effect of Ce/Sm dipping. Investigations show that:Resulting from the dipping of Ce/Sm, in the process of heat treatment, decomposation of organic substances were promoted, growth of TiO2 grains was retarded, and the commencing temperature of Titanium-Rutile transformation was delayed from 600℃to 690℃by Ce/Sm dipping. A homogeneous, transparent and flawless thin film was obtained by a following heat treatment at 250℃, and no spot was observed after recycling testing.As the increase of thickness, the color of TiO2 thin films changed from light blue to blue gradually, in the process of electrochromic property testing. When the thickness was kept from 90-120 nm, the storage capacity of electric was optimized as 18.90m C·cm-2 and K was climbed to a maximum value of 0.91, the reversibility of electrochromic properties ranked the best.When Ce/Sm was dipped into TiO2 thin films, the electrochromic properties were weakened and no apparent spot was observed. As the increase of dipping consistency, current-response performance was faded. When the dipping molar-consistency of Ce attained 2%, K climbed to a maximum value of 0.88 and the electrochromic properties of the films were the best; When the dipping molar-consistency of Sm attained 10%, K peaked at 0.95, which hence the best elctrochromic properties too.