Comparison of PEDOT films obtained via three different routes through spectroelectrochemistry and the differential cyclic voltabsorptometry method (DCVA).

The performance of different poly(3,4-ethylenedioxythiophene) (PEDOT) films was compared by electrochemical, spectroelectrochemical, and time-derivative measurements of absorbance versus potential (linear potential-scan voltabsorptometry) for an overall spectroelectrochemical characterization of the electrochromic properties in ionic liquids such as 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMITFSI). The time-derivative signals were monitored at different wavelengths, and information obtained therefrom was complementary to that obtained from conventional cyclic voltammetry. PEDOT films prepared via in situ chemical oxidative polymerization appeared to be much more efficient than electropolymerized and PEDOT-poly(styrenesulfonate) (PSS) reference films, in terms of both contrast ratio and coloration efficiency, which was the case even for PEDOT films deposited on less conductive flexible plastic substrates.

New Fluorinated Stannic Compounds as Precursors of F-Doped SnO(2) Materials Prepared by the Sol-Gel Route.

Dialkoxydi(beta-diketonate)tin(IV) compounds react either with difluorodi(beta-diketonate)tin(IV) or with butanoyl fluoride to yield novel tin complexes Sn(OR(1))F(R(2)COCHCOR(2))(2) 1 (R(1) = tert-amyl, isopropyl, ethyl; R(2) = methyl, tert-butyl). Multinuclear (1)H, (13)C, (19)F, and (119)Sn NMR spectroscopic characterization showed that complexes 1 are octahedral in solution with a cis configuration for the fluorine and the alkoxide group. Kinetics of configurational rearrangements were studied by variable-temperature (13)C NMR spectroscopy. The hydrolytic behavior of 1 was determined for different hydrolysis ratios h = [H(2)O]/[1]. For R(1) = tert-amyl, a dimeric fluorinated species was mainly obtained for h = 0.5, and addition of 2 mol equiv of water led to a fluorinated stannic oxopolymer soluble in CH(3)CN. In the latter case, the powder obtained after solvent elimination and treatment in air at 550 degrees C consisted of crystalline SnO(2) cassiterite particles containing the required amount (3 mol %) of doping fluorine and exhibiting electronic conductivity comparable to that of Sn-doped In(2)O(3). Complexes 1 are the first precursors of F-doped SnO(2) materials prepared by the sol-gel route.