Doped reflectance spectra

The UV-visible diffuse reflectance spectrum of N-doped HO2 (anatase), which was prepared by the sol-gel method, is compared with that of bare T1O2 (anatase) in Fig. 6.14. The two spectra essentially differ for the broad absorption in the... 

The propyl thiol substituted PANI was studied by reflectance FTIR using Nicolet NEXUS 870. The polymer was treated with IM aqueous NaOH solution to remove the doped HCl from the polymer. The polymer was washed with water and then, it was dried under continuous vacumn for 24 hr. The FTIR reflectance spectrum of sodium polyaniline propyl thiol sulfide (NaPAPS) was obtained and compared with the FTIR reflectance spectrum of emeraldine base. 

Another study reported that to obtain carbon-doped 1102, oxidation at 350°C for more than 50 h was recommended without any annealing in O2 atmosphere [159]. The substituted carbon atoms were confirmed by the Cls spectrum of XPS at 282 eV, which was due to the Ti-C bond (281.9 eV). Ti2p peaks in its XPS spectrum were not different from those of pure Ti02. It was also reported that carbon-doped Ti02 with high photocatalytic activity can be obtained from TiC by oxidation at 350°C for 8 h [160] in this case the amount of substituted carbon was about 0.7 mass%. This material was gray-white in color and its diffuse reflectance spectrum showed a red shift of 36 nm compared with pure anatase-type 1102. Its photoactivity under visible light irradiation was confirmed by the decomposition of trichloroacetone. 

Figure 13-10. (a) TEM image of a microcavity reflector made up ofEu-doped SiOx/TiOz multilayer, and (b) a reflectance spectrum for a cavity with seven pairs of alternated layers. The arrow indicates a, sharp dip due to the cavity resonance (Bellessa, 2001). 

PTh has been doped chemically and electrochemically. The cleanest spectra are obtained with spectroelectrochemical reflection methods using C104 as counterion [125]. Since data are reported as difference spectra the doping induced spectrum is clearly exhibited since the unreacted background has been subtracted ( fig.7). Infrared spectra with chemical doping have been presented by Cao et al.[126] the authors of ref.126 have doped also the oligomers. ... 

Electronic spectra (Table 1.1, Fig. 1.2) have been measnred for the orange soln-tions of (RuO ] in aqueous base from 250-600 nm. [212-215, 222], and reproduced [215, 222]. There are two at 460 and 385 nm. [212, 213, 222] or three bands in the visible-UV region, at 460, 385 and 317 nm [214, 215]. These appear to be at the same positions as those for [RuO ] but the intensities and hence the general outline of the two spectra are very different. Woodhead and Fletcher reviewed the published molar extinction coefficients and their optimum values / dm (mol" cm" ) are 1710 for the 460 nm. band, 831 for the 385 nm. band and 301 for the 317 nm. band - the latter band was not observed by some workers [214]. The distinctive electronic spectrum of ruthenate in solution is useful for distinguishing between it, [RuO ]" and RuO [212, 222]. Measurements of the electronic spectra of potassium ruthenate doped in K CrO and K SeO and of barium ruthenate doped into BaSO, BaCrO, and BaSeO (in all cases the anions of these host materials are tetrahedral) indicate that in that these environments at least the Ru is tetrahedrally coordinated. Based on this evidence it has been suggested that [RuO ] in aqueous solution is tetrahedral [RuO ] rather than franx-[Ru(0H)3(0)3] [533, 535]. Potential modulated reflectance spectroscopy (PMRS) was used to identify [RuO ] and [RuO ] " in alkaline aqueous solutions during anodic oxidation of Ru electrodeposited on platinum from [Ru3(N)Clg(H30)3] [228]. 

Metallic polymers have a lower density of electrons both the length of the repeat unit along the chain and the interchain spacing are relatively large compared to the interatomic distances in conventional metals. Typically, for metallic polymers N is of the order 5 x 10 cm . Thus, for metallic polymers, the plasma frequency is at approximately 1 eV [66,67]. The reflectance of high quality, metallic polypyrrole (doped with PF ) is shown in Fig. III-2. Metallic polymers exhibit high reflectance (and thus look shiny ) in the infrared, but they are semitransparent in the visible part of the spectrum. The residual absorption... 

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