NMR spectroscopic, linear and non-linear optical properties of 1,3-benzothiazol-2-yl-(phenylhydrazono)acetonitrile (BTPA) azo dye

A novel organic semiconductor 4-phenylthiazol-2-yl-(phenylhydrazono) acetonitrile (PTPA) thin films: synthesis, optical and electrical properties

In this study, 4-phenylthiazol-2-yl-(phenylhydrazono) acetonitrile (PTPA) azo dye was synthesized and studied from optical and electrical point of view. The tautomerization phenomenon of the PTPA dye was clarified using one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (1HNMR and 13C NMR), absorbance (UV-Vis), emission, and Fourier transform infrared spectroscopy (FT-IR). X-ray diffraction (XRD) evaluations were indicated that PTPA in powder and thin films crystallizes in a monoclinic system structure with nonstructural characteristics. Spectrophotometric measurements of absorbance A (λ), transmittance T (λ) and reflectance R (λ) at normal incidence light in the wavelength range 200-2500 nm were used to determine the optical band gap, extinction coefficient, k and refractive index, n. Also, non-linear optical parameters such as the third order non-linear susceptibility, χ(3) and nonlinear refractive index, n(2) of PTPA have revealed an awe-inspiring switching behavior, implying the possibility of using PTPA in optical switching systems. Finally, the electrical conductivity of the PTPA was shown to increase with rising temperature, indicating that it is a typical organic semiconductor. Mott's parameters were determined and discussed at low temperatures. Thus, PTPA is a promising organic semiconductor with broad utility potential in organic electronics such as organic light-emitting diodes (OLEDs).

Morphological, structural, and optical properties of flexible Tin Oxide(II) thin film via thermal evaporation technique

Tin oxide compounds have been highly studied due to their important properties. Tin Oxide (II) SnO compound is considered an ideal p-type conductive material, with large p-type carrier mobility. It is getting a lot of attention in next-generation electronic applications. In this work, the SnO thin film was deposited on the polyethylene terephthalate (PET) substrate by the thermal evaporation method. The X-ray diffraction pattern revealed the amorphous structure of the SnO/PET thin film. The purity of the SnO/PET film was confirmed using the Raman spectrum. An atomic force microscope was carried out to investigate the topography (roughness and particle size) of the obtained SnO thin film. The optical band gap $$E_{{\text{g}}}^{{{\text{Opt}}}}$$ E g Opt for SnO/PET thin film in the absorption region was estimated using Tauc’s equation. The refractive index for the SnO/PET thin film was estimated at the normal dispersion range by a single oscillator model. The dielectric optical properties of the SnO/PET thin film were estimated. The calculated third-order nonlinear susceptibility χ(3) and nonlinear refractive index n(2) were in the order of ~ 10−10 and ~ 10−9esu, respectively, within the photon energy range (0.5 to 4 eV). The Sheik–Bahae model was used to determine the nonlinear absorption coefficient βc for SnO/PET thin film. Based on these detailed results, the high nonlinear optical parameters pave the way for the probability of using the SnO/PET in flexible optoelectronics devices.

Graphical abstract

Synthesis of new azobenzo[c]cinnolines and investigation of electronic spectra and spectroelectrochemical behaviours

A series of disazobenzo[c]cinnoline dyes was prepared by coupling reaction of 3,8-dihydroxybenzo[c]cinnoline with diazotised aromatic amines. The structures of these dyes were confirmed using UV-Vis, FTIR, ¹H NMR, LC-MS/MS and LC-MS/TOF spectroscopic techniques. ¹³C NMR, ¹³C-DEPT, ¹H-¹H COSY, ¹H-¹³C HMQC and ¹H-¹³C HMBC spectra of dye 12 were demonstrated in this study. In addition, the effects of the substituent attached to the phenyl ring, solvent and acid-base on the UV-Vis spectra of the dyes were investigated. Besides, voltammetric and spectroelectrochemical behaviours of four disazobenzo[c]cinnolines (2, 8, 11 and 13) in acetonitrile (ACN) solution were also evaluated. It was observed that the disazobenzo[c]cinnoline derivatives indicated reversible voltammetric behaviour in acetonitrile-tetrabutylammonium perchlorate (ACN-TBAP) solution. A square-wave potential step method coupled with optical spectroscopy was used to probe switching times and optic contrast of the dyes.

Synthesis, spectroscopic, electrochemical and photophysical properties of high band gap polymers for potential applications in semi-transparent solar cells

BACKGROUND

The design of new polymers able to filter the electromagnetic spectrum and absorb distinctly in the UV and high-energy part of visible spectrum is crucial for the development of semi-transparent solar cells. Herein, we report on the synthesis and spectroscopic, electrochemical, and photophysical characteristics of three new polymers, namely (i) Poly(triamterene-co-terephthalate), (ii) Poly[triamterene-co- 3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine-p,p'-disulfonamide], and (iii) Poly(5-hydroxyindole-2-carboxylate) that might show promise as materials for semi-transparent solar cells.

RESULTS

The energy band gap, refractive index, dielectric constant, and optical conductivity of the electron donor polymer, poly(triamterene-co-terephthalate), were determined to be 2.92 eV, 1.56, 2.44 and 2.43 × 104 S cm-1, respectively. The synthesized electron acceptor polymers showed a relatively high refractive index, dielectric constant, and optical conductivity. The presence of a direct allowed transition was confirmed between intermolecular energy bands of the polymers.

CONCLUSIONS

The polymers showed relatively high energy gap and deep HOMO levels, making them strong absorbers of photons in the UV region and high energy part of the visible region. The synthesized donor and acceptors performed well relative to P3HT and fullerenes due to the close match of the HOMO and LUMO levels. With further development, the polymers could be viable for use as the active layers of semi-transparent solar cells.