Electrochemical Synthesis of Chromogenic Rare Earth Doped Vanadium Oxide Films

摘要

The rare earth metal of Pr,Nd and Ce (RE) ions doped vanadium oxide films were synthesized on the ITO electrode by electrolysis in molten dimethylsulfone (DMSO_2)-RECl_3, DMSO_2-RECl_3-LiNO_3, DMSO_2-RE_2O_3, DMSO_2-RE_2O_3-V_2O_5 and bisulfate(NH_4HSO_4)-RE_2O_3-V_2O_5(NH_4VO_3) systems at the temperature about 150-250℃. The RE element and vanadium content in melts was analyzed by ICP. The obtained films were analyzed by x-ray diffraction and optical absorption spectra. Moreover, the electrochromic (EC) reactions of the RE ions doped vanadium bronze films in room temperature solution of propylene carbonate were investigated. The amount of the soluble RE ions was considerably increased by the addition of vanadium oxides in molten salt. This increase of solubility was attributed to the acid-base and redox reaction between vanadium oxides and RE oxides in molten salts. The good effect of addition of alkaline nitrates for formation of RE ion doped vanadium bronze films by electrolysis was observed. The luminescence thermochromic and EC properties of RE ions doped vanadium bronze films were measured. The intensity of the luminescence peaks at 470 nm, 535 nm for vanadate ions were increased by doping RE ions. The absorption spectrum of praseodymium oxide films obtained by electrodeposition in DMSO_2-Pr_6O_(11)-LiNO_3 systems had 640 nm and 410nm peaks due to mixed valence of Pr~(3+)andPr~(4+). The Ce or Nd ions doped vanadium oxide films were discussed on the basis for chromogenic property as EC and luminescence thermochromic materials.