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Highlights: [•] Nano-pentacene thin film was prepared via thermal evaporation. [•] Optical constants and optical dispersion parameters were calculated. [•] The complex dielectric constant and the band gap were determined. [•] The optical conductivity σopt , (VELF) and (SELF) functions were calculated. [•] Pentacene is a good candidate for the organic thin film transistor. [Copyright &y& Elsevier]

Abstract: The effects of the molar ratio of stabilizer on structural and optical properties of ZnO nanocrystalline films have been investigated. The AFM images indicate that the ZnO films are formed from the nanofibers. The optical transmittance spectrum indicates the average transmittance higher than 85% at higher wavelengths. In UV spectrum, the transmittance increases with followed by a slight decay within visible range. The results of the absorption coefficient were analyzed in order to determine the optical band gap of the films. The optical constants (refractive index and absorption index) of the thin films were determined. Moreover, the dispersion parameters such as dispersion energy, oscillator energy, dielectric constants and dissipation factor were determined. The most significant result of the present study is to indicate that the molar ratios of MEA to ZnAc in the prepared ZnO nanocrystalline films have a little effect on the optical band gap but can be used to modify the optical dispersion parameters of the prepared ZnO nanocrystalline thin films. [Copyright &y& Elsevier]

Abstract: The optical properties of 2(3),9(10),16(17),23(24)-tetrakis-{6-(-benzofuran-2-carboxylate)-hexylthio} phthalocyaninatozinc(II) {Zn[Pc(b-S(CH2)6OCOBz-furan)4], (ZnPcBzF) thin film prepared by spin coating method were investigated. The optical constants of the prepared film were determined using spectrophotometric measurements of the transmittance and reflectance at normal incidence in the spectral range 200–800nm. The analysis of the spectral behavior of the absorption coefficient in the intrinsic absorption region revealed two direct allowed optical band gap of 2.58 and 3.87eV. The dispersion of the refractive index was discussed in terms of the single oscillator using Sellmeier dispersion formula. The high frequency dielectric constant (ε ∞ ) and the lattice dielectric constant (ε L ) were estimated. From the optical constants analysis, the optical conductivity was also considered. Discussion of the obtained results and their comparison with the previous published data were also given. The obtained results of this new zinc phthalocyanine benzofuran derivative (ZnPcBzF) support the desirable feature for the microelectronic and optoelectronic devices. [Copyright &y& Elsevier]

Rhodamine B (RhB) films prepared via spin coater on polyacetate flexible substrates. The X-ray diffraction spectroscopy has been done for RhB/polyacetate flexible substrate and displays an amorphous structure of RhB films in the various thicknesses in the range of 74–303 nm. K-K relations used for determining the refractive index and exhibits a normal dispersion at λ > 600 nm and an anomalous dispersion at λ < 600 nm. The electronic transitions reveal two bands of absorbance Q band which due to the first π→π* transitions and Soret band due to the second π → π * transitions. Also, other linear optical constant such as absorption coefficient, band energy gap, dielectric constants, and optical conductivity were discussed. On the other hand, the first (χ (1) ) and third (χ (3) ) orders of nonlinear optical susceptibilities as well as a nonlinear refractive index (n 2) were calculated and discussed. The electrical and optical conductivities demonstrated the high absorption of RhB/flexible substrates inferring the chance of utilizing these films as optoelectronic gadgets. • Flexible optoelectronic materials have an increasing interest in the advancement of solar energy and biomedicine. • Investigated the optical spectroscopy by Kramers-Kronig (K‑K) method For Rhodamine B (RhB) films. • Calculated the nonlinear optical constants (χ(1)), (χ(3)) and nonlinear refractive index (n 2). • Calculated the electrical and optical conductivities. [ABSTRACT FROM AUTHOR]