New bisimide derivatives, low molecular compounds with π-π* conjugated system consisting of a pyromellitic diimide core and imine linkages were synthesized by Schiff bases reactions, the studied compounds were prepared from N,N'-bis amino pyromellitic diimide which was condensed with different derivatives of aldehydes, the materials show a high melting point and some above 300 ◦C depended intramolecular attractive and the Vander Waals attraction between various substituent groups. The optical properties of the prepared compounds were investigated by UV–vis measurement. The prepared compounds showed the highest intensity with maximum absorbance at 243-908 nm. In all studied molecules, the electrochemically estimated theoretical HOMO level is in the range of -7.515 to -7320 eV, whereas the LUMO level is close to 7.219 eV and -5.889 eV. The estimated compounds exhibited low electrochemical band gap (<2 eV).

The effects of higher order excitations on the bandgap renormalization of quasi-one dimensional semiconductor systems within the dynamical random phase approximation is studied. The contribution of the first and second excited states wave functions is incorporated in the calculation of the bandgap narrowing due to many-body exchangecorrelation effects. It is shown that incorporation of the higher order excitations leads to the result that absolute values of the bandgap narrowing in these cases are larger than the corresponding renormalization which is calculated by only considering the ground state wave function.

In this paper design and analysis of bandgap voltage reference with CMOS transistor for elimination of temperature and source voltage effect is presented. In this paper, by applying techniques such as the base current provider circuit to independent the output voltage from the fabrication process, as well as using a large capacitor and self-bias cascade current mirrors with high swing, the power supply rejection ratio, without affecting the spectral density power, improves. In this design self bias cascade current mirror with high swing is used for decreasing the effect of bias voltage on the output voltage. Two base-emitter voltage with series structure is used for compensation of transistors mismatches, also it used circuits for base current compensation for designing of output voltage independent from the production process, and large capacity for removing external interference. Simulation result of designed bandgap voltage reference with ADS achieves output voltage of 1. 236V; PSRR and output power spectral density at frequency of 100HZ obtained-109. 94 dB and 3. 072 nv/√ HZ, respectively. Also, the output voltage temperature coefficient is 28. 3 ppm/℃ at-40 ℃ to 120 ℃ .

Compared to the long history of plasmonic gratings, there are only a few studies regarding the bandgap in the propagation of plasmonic surface waves. Considering the previous studies on interpretation of plasmonic bandgap formation, we discuss this phenomenon using the effect of both surface plasmon polariton (SPP) and localized surface plasmon (LSP) for our fabricated onedimensional metallic-polymeric grating. This structure is composed of metallic grating on the surface of PDMS with different concentration of embedded gold nanoparticles. By sweeping the incident angles, we have seen that the SPP, LSP and their coupling cause two gaps in reflection regime which are originated from SPP supported by thin film gold film and LSP supported by gold nanoparticles. The first gap is attributed to the patterned metallic film because it vanishes by increasing the nanoparticles which may destroy the pattern while the second gap can be formed by embedded nanoparticles because it becomes more considerable by raising the incubation time. Therefore, the drowning time of patterned samples (e. g. 24h, 48h, and 72h) in HAuCl4 plays the key role in adjustability of plasmonic bandgap. Notably, the interaction between SPP and LSP can be the origin of the shift in gap center from 300 to 550. To best of over knowledge, this study is the first study on the plasmonic band gap as a function of both SPP and LSP.

Titanium-di-oxide nanoparticles are synthesized via a microwave-assisted solvothermal route for different pH values. The effect of the acidic and basic nature of the solvent due to the pH value is reflected in the crystalline size of the compound. The purpose of this work is to synthesize Titanium dioxide nanoparticles and to observe their application in degrading industrially contaminated water using normal tap water. The crystalline sizes are calculated using XRD analysis and confirmed with HRTEM. The chemical composition and oxidation state are confirmed with XPS studies. Optical properties are carried out with UV-Vis, FTIR, and PL spectra. Photocatalytic studies are carried out to degrade the dye in industrial water. The efficiency of degradation is calculated with the UV-Vis data and formula. The reduction in band gap and high permanence has greatly supported in making it acceptable for photocatalytic activity under visible light. Dependence of time, initial dye concentration, and pH of the dye solution on TiO2 as a catalyst is investigated under the illumination of a visible lamp, and degradation efficiency to the highest of 96.79% has been obtained.

The physical properties of Zr-doped CrS films were examined in-depth in this study, focusing on the influence of precursor temperature during electrochemical deposition for photovoltaic use. The spectra show a decrease in absorbance from 300 to 600 nm in the visible range and an increase from 650 to 1100 nm in the ultraviolet range. The transparency of chromium sulfide films is enhanced by adding a zirconium dopant at precursor temperatures ranging from 45 to 55 oC. The energy bandgap of Zr-doped CrS and CrS varies between 2.35 and 3.33 eV. As the precursor temperature increases, the crystallite size of the CrS and Zr-doped CrS material increases. This shows a better quality and growth of the material's grains. Precursor temperature influences the crystal structure of CrS and Zr-doped CrS films. The studies revealed that variations in the precursor temperature influence the film's crystallinity, phase composition, and grain size.