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Pyronin Y (PY) is an organic dye which is used extensively before in staining RNA and other organo-cells. Nowadays, it can be used in electronic and optoelectronic devices as an organic semiconductor. X-ray diffraction (XRD) showed that PY is a polycrystalline material and both the lattice structure and the lattice constants were calculated for the first time by using crysfire and checkcell software. In addition, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and differential thermal analysis (DTA) have been studied. Diffused reflectance (DR) of pyronin Y in the wavelength 200–2300 nm was measured and analyzed to calculate the optical parameters and the absorption region of pyronin Y. The optical band gap was calculated on the basis of Kubelka–Munk theory (KMT). It is clear that there are three optical band gaps in the studied range of photon energy and equal 2.13, 1.82 and 1.67 eV. The high band gap (2.13 eV) is corresponding to the fundamental band gap (between HOMO and LUMO) and other two gaps (1.82 and 1.67 eV) are corresponding to the trap energy inside the band gap (i.e. onset gaps). On the basis of the DR measurements and applicable of KMT, we are able to calculate the refractive index, absorption index and the dielectric constants for pyronin Y in powder form. Pyronin Y is an organic semiconductor due to the increasing of DC (direct current) electrical conductivity with increasing temperature and the electronic parameters of direct current was calculated. Ac electrical conductivity, dielectric constant and dielectric loss were calculated and interpreted on the basis of ac fields causes the different kind of polarization inside the materials. Hence, pyronin Y can be used as a new materials for advanced technology. [ABSTRACT FROM AUTHOR]

Abstract: Thin films of ZnGa2Se4 were deposited by thermal evaporation method of pre-synthesized ingot material onto highly cleaned microscopic glass substrates. The chemical composition of the investigated compound thin film form was determined by means of energy-dispersive X-ray spectroscopy. X-ray diffraction XRD analysis revealed that the powder compound is polycrystalline and the as-deposited and the annealed films at T a =623 and 673K have amorphous phase, while that annealed at T a =700K is polycrystalline with a single phase of a defective chalcopyrite structure similar to that of the synthesized material. The unit-cell lattice parameters were determined and compared with the reported data. Also, the crystallite size L, the dislocation density δ and the main internal strain ε were calculated. Analyses of the AFM images confirm the nanostructure of the prepared annealed film at 700K. The refractive index n and the film thickness d were determined from optical transmittance data using Swanepoel''s method. It was found that the refractive index dispersion data obeys the single oscillator model from which the dispersion parameters were determined. The electric susceptibility of free carriers and the carrier concentration to the effective mass ratio were determined according to the model of Spitzer and Fan. The analysis of the optical absorption revealed both the indirect and direct energy gaps. The indirect optical gaps are presented in the amorphous films (as-deposited, annealed at 623 and 673K), while the direct energy gap characterized the polycrystalline film at 700K. Graphical representations of ε 1, ε 2, tan δ, −Im[1/ε*] and −Im[(1/ε*+1)] are also presented. ZnGa2Se4 is a good candidate for optoelectronic and solar cell devices. [Copyright &y& Elsevier]

Abstract: Optical properties of the interaction between thiophanate methyl and human serum albumin have been investigated for biosensor applications. The interaction between human serum albumin (HSA) and thiophanate methyl (MT) was investigated by UV–Vis absorption spectra and atomic force microscopy. The optical constants (refractive index, absorption index, band gap and dielectric properties) of HSA, MT and MT+HSA films were determined using absorbance, transmittance and reflectance spectra. The refractive index dispersion curve (>530nm) exhibits the normal dispersion. The refractive index of the MT+HSA is higher than both HSA and MT alone due to the highest reflectance of the mixture of MT and HSA. This behavior is indicative of the complex formation between the MT and HSA. [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]