Electrochromic and structural investigation of InVO4 and some other vanadia-based oxide films
2001; Elsevier BV; Volume: 46; Issue: 13-14 Linguagem: Inglês
10.1016/s0013-4686(01)00406-6
ISSN1873-3859
AutoresBoris Orel, Angela Šurca Vuk, Urša Opara Krašovec, Goran Dražić,
Tópico(s)Luminescence Properties of Advanced Materials
ResumoWe extended our previous studies of M3+VO4 orthovanadate (M3+=Ce, Fe) and M23+V4O13 (Fe2V4O13) films to include InVO4 films because their photopic transmittance Tvis(initial) is above 0.885. Structural studies (TEM and XRD) revealed that films prepared from In(NO3)3·5H2O and V-oxoisopropoxide sols annealed at 500°C consist of the mixed monoclinic (InVO4-I) and orthorhombic (InVO4-III) phases, while the addition of acetylacetone (acac) to the sol results in amorphisation. The charge capacity of InVO4/acac films is between −30 and −40 mC cm−2 (single dipped films) and their electrochemical stability is more than 1000 cycles. In situ UV–visible spectroelectrochemical measurements show that charging to −35 mC cm−2 decreases the photopic transmittance from Tvis(initial)=0.885 to Tvis(ins)=0.722, which contrasts the higher optical passiveness of previously investigated CeVO4 films (Tvis(ins)=0.90). The increase in the broad absorption below 600 cm−1 in IR spectra of charged/discharged InVO4 films shows that films irreversibly uptake lithium ions. Charging up to −20 mC cm−2 does not affect the IR spectra, while charging up to −40 mC cm−2 results in the transformation of the film structure, which becomes similar to that of the amorphous InVO4 films obtained at 300°C and to certain transition vanadate glasses. IR spectra of other vanadia-based films, i.e. FeVO4, Fe2V4O13, CeVO4, and V2O5 films in different state of lithiation are discussed.
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