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A newly oxospiro[indoline-3,4′-pyran]-5′-carbonitrile derivative has been synthesized and characterized by FT-IR, NMR spectroscopies, and elemental analysis. The compound thin film form has been prepared by spin coating technique. The optical absorbance, transmittance, and reflectance measurements were carried out in the wavelength (300–2500 nm) range. The absorption and dielectric parameters were determined and discussed. The electronic transition energies (2.56, 3.45& 3.97 eV) were deduced and correlated to the onset, optical, and transport gaps, respectively. The electrical resistance and Seebeck coefficient measurements revealed the n-type semiconducting behavior of the films. The detected rapid reversibility of the O 2 - chemisorption process on the surface of the present films at room temperature was exploited for the NH 3 gas sensing application. The revealed fast reversibility, low response (180/224 s) and recovery (3 s) times, good selectivity, as well as the long-term stability of the present films, prove their promises for RT-NH 3 gas sensing applications. [Display omitted] • Optical and electrical characterization of newly synthesized organic compounds. • Discussion of the electronic transition energies through HOMO-LUMO orbitals. • n-type conduction behavior revealing by the present film. • Proof of the film ability for RT-NH3 gas sensing. [ABSTRACT FROM AUTHOR]

Comparison of the absorption spectra of the ethanolic solution (3 ppm) of some diethyl 3,4-diaminothieno[2,3- b ]thiophene-2,5-dicarboxylate (TT amino ester) derivatives has revealed that the azo dye derivative compound 4 manifests smaller band gap and higher absorption maximum close to solar maximum wavelength. Very good adhesive thin films to glass substrates of the azo dye compound 4 have been successfully prepared by thermal evaporation technique. The optical spectral analysis of such compound film revealed three absorption transitions corresponding to the optical gap, the electron transition between impurity levels in band gap and the fundamental band gap (HOMO to LUMO π → π * transitions). Absorption, dielectric and dispersion parameters have been determined for as- deposited and gas treated films and discussed. This film manifested a fast response and high sensitivity toward iodine vapor with a reasonable recovery time indicating a reversibility of iodine adsorption process. In contrast, the film illustrated slow response and weak sensitivity toward HCl gas with irreversible adsorption process. Besides, the azo dye compound 4 solution manifests strong emissive properties that recommend it as promising candidate for fluorescence sensors. [ABSTRACT FROM AUTHOR]

(V 2 O 5) 1-x Zn x powdered samples with different light doping levels (x = 0.03–0.09) were prepared by a solid-state thermal reaction and studied by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), energy dispersive analysis (EDAX), and optical diffuse reflectance spectroscopies. The prepared samples has been revealed that the increments in Zn-doping levels accompanied by vacuum heat treatment lead to the appearance of an additional V 12 O 26 phase beside the pure V 2 O 5 oxide, resulting not only in more donor vanadium atom liberation but also in multi-heterojunction component formation. Besides, Eg values decrease from 2.38 to 2.2 eV as Zn doping increases from x = 0 to x = 0.09. All previous observations improve the process of purifying water from pollutants by increasing the number of free carriers of V 2 O 5 powder by adding Zn atoms and making vacuum heat treatments. The photocatalytic examination has been carried out using constants of 0.5 g and 0.01 g/L (10 ppm) of the catalyst quantity and MB-dye concentration, respectively, under Vis – irradiations. The acidic solution medium with a pH of 2 strongly motivated the degradation activity. The highest catalytic efficiency of 99.78% was attained by the (V 2 O 5)0.91 Zn 0.09 compound within a time of 70 min and continued invariably for 5 hours in the dark. These catalytic results have proved the possibility of their reusability. [ABSTRACT FROM AUTHOR]