Structural, Optical, and Electrical Parameters of Doped PVA/PVP Blend with TPAI or THAI Salt.

The 70% polyvinyl alcohol/30% polyvinyl pyrrolidone (PVA/PVP) polymer blends, with different weight ratios of tetrapropylammonium iodide (TPAI) or tetrahexylammonium iodide (THAI) salt, were prepared using dimethyl sulfoxide (DMSO) as a solvent. The X-ray diffraction technique was used to trace the crystalline nature of the formed blends. The SEM and EDS techniques were applied to figure out the morphology of the blends. The variation in the FTIR vibrational bands was used to investigate the chemical composition and the effect of different salt doping on the functional groups of the host blend. The influence of the salt type (TPAI or THAI) and its ratio on the linear and nonlinear optical parameters for the doped blends were investigated in detail. Absorbance and reflectance are highly enhanced in the UV region reaching a maximum for the blend with 24% TPAI or THAI; so, it can be employed as shielding materials for UVA and UVB types. The direct (5.1 eV) and indirect (4.8 eV) optical bandgaps were reduced continuously to (3.52, 3.63 eV) and (3.45, 3.51 eV) while increasing the content of TPAI or THAI, respectively. The blend doped with 24% wt TPAI exhibited the highest refractive index (around 3.5 in 400-800 nm). The DC conductivity is affected by the content and type of salt, its dispersion, and blend-salt interaction. The activation energies of different blends were obtained by applying the Arrhenius formula.

Development of Perovskite (MACl)0.33FA0.99MA0.01Pb(I0.99Br0.01)3 Solar Cells via n-Octylammonium Iodide Surface Passivation.

The influence of n-octylammonium iodide (OAI, passive layer) on the types of phases formed in a (MACl)0.33FA0.99MA0.01Pb(I0.99Br0.01)3 perovskite film was studied using X-ray diffraction. Using UV spectrophotometric techniques, it was determined how varied OAI additive layer ratios affected the linear and nonlinear optical characteristics of glass substrates/FTO/compact TiO2/mesoporous TiO2/(MACl)0.33FA0.99MA0.01Pb(I0.99Br0.01)3 films. All films' direct optical bandgap energies were determined to be 1.54 eV. The effects of OAI addition on the films' photoluminescence intensity and emitted colors were also investigated. For the fabricated perovskite solar cells (PSCs) without an OAI passivation layer, the corresponding power conversion efficiency (PCE), open-circuit voltage (VOC), short-circuit current density (JSC), and fill factor (FF) values were 18.8%, 1.02 V, 24.6 mAcm-2, and 75%, respectively. When the concentration of OAI reached 2 mg, the maximum obtained values of PCE, VOC, JSC, and FF were 20.2%, 1.06 V, 24.2 mAcm-2, and 79%, respectively. The decreased trap density and increased recombination resistance were responsible for the improvement in solar cell performance.

Impact of ZnS/Mn on the Structure, Optical, and Electric Properties of PVC Polymer.

The most efficient way to create novel materials that may be used in a variety of optoelectronic applications is thought to be doped mixed polymers with appropriate fillers. Undoped and doped PVC polymers with ZnS/Mn formed at different temperatures were fabricated using the casting method. The Rietveld method was used to discover the structure and microstructure of Zn0.95Mn0.05S prepared at T = 300, 400, and 500 °C. The distribution and existence of the nanofiller over the PVC matrix were determined via XRD, FTIR, EDS, and SEM techniques. The effect of the preparation temperatures of the ZnS/Mn nanofiller on the absorption, transmittance, reflectance, refractive index, extinction coefficient, dielectric constant, AC conductivity, electrical modulus, and DC conductivity activation energy data of the PVC polymer was studied using the diffused reflectance technique. Doping PVC with ZnS/Mn (prepared at 300 °C) lowered the direct and indirect optical band gaps from 5.4 and 4.52 eV to minimum values of 4.55 and 3.63 eV. The fluorescence intensity of pure PVC is greatly enhanced upon loading with ZnS/Mn. The PVC exhibited two near UV peaks, one violet and one blue color, while, in addition, the doped polymers exhibited green and orange colors. The corresponding CIE diagram for all the samples was also determined.

Laser induced infrared spectral shift of the MgB2:Cr superconductor films.

During illumination of the MgB2:Cr2O3 films it was established substantial spectral shift of the infrared spectra in the vicinity of 20-50cm(-1). The excitations were performed by nanosecond Er:glass laser operating at 1.54µm and by microsecond 10.6µm CO2 laser. The spectral shifts of the IR maxima were in opposite spectral directions for the two types of lasers. This one observed difference correlates well with spectral shift of their critical temperatures. The possible explanation is given by performance of DFT calculations of the charge density redistribution and the time kinetics of the photovoltaic response. To understand the kinetics of the photoinduced processes the time kinetics of photoresponse was done for the particular laser wavelengths.

IR laser induced spectral kinetics of AgGaGe3Se8:Cu chalcogenide crystals.

The possibility to operate by optical spectra near the absorption edge gap was discovered for the AgGaGe3Se8:Cu semiconducting chalcogenide crystals under influence of microsecond CO2 laser with pulse energy 60 mJ operating at wavelength 10.6 µm. An occurrence of substantial photoinduced optical density was observed at wavelengths in the spectral range of 610-620 nm. Introducing of Cu ions leads to substantial spectral asymmetry in the observed spectra. The process achieves its maximum value after the 80-120 s of CO2 laser treatment and relaxes with almost irreversible changes after the same time. The contribution of thermo heating did not exceed 5-6%. Only the irreversible changes of the sample's surface topography were observed during the CO2 laser treatment, which do not influence the treatment. So the surface states do not play a principal role and the effect is prevailingly originated from the. The observed effect may be used for control of the CO2 laser power density.

Synthesis and antimicrobial activity of some new 2-chloro-4-nitrobenzoylamino acid and dipeptide derivatives.

The synthesis of a series of 2-chloro-4-nitrobenzoylamino acid methyl esters (II-VIII), corresponding hydrazides (IX-XV), dipeptide methyl esters (XVI-XXII) and dipeptide hydrazides (XXIII-XXIX) was achieved employing the carbodiimide and azide methods. The derivatives containing the residues of Phe and Tyr were found to be active against several microorganisms.

Synthesis of some 1-acetylindoline-5-sulphonylamino acid derivatives and studies of their antimicrobial activities.

The synthesis of a series of 1-acetylindoline-5-sulphonylamino acids and some of the corresponding methyl esters and hydrazides (II-XXIII) is described. Coupling of 1-acetylindoline-5-sulphonylamino acids with amino acid methyl ester hydrochlorides in THF-Et3N medium, using the dicyclohexylcarbodiimide method gave the desired 1-acetylindoline-5-sulphonyldipeptide methyl esters (XXIV-XXVIII). Most of the synthetic 1-acetylindoline-5-sulphonylamino acid and dipeptide derivatives (II-XXVII) were found to possess various antimicrobial activities against a number of microorganisms.

Synthesis of some isonicotinoyl- and nicotinoyl-sulphonylamino acid derivatives and their antimicrobial activity.

The synthesis of isonicotinoylamino acids-2-sulphonylamino acids and nicotinoylamino acids-5-sulphonylamino acids (III-VII) and (XXIII-XXVII) and their corresponding methyl esters, hydrazides and some dipeptide methyl ester derivatives (VII-XXII) and (XXVIII-XXXVII) are described. Thirty two of various substituted nicotinoyl and isonicotinoyl sulphonylamino acid derivatives were found to possess specific antimicrobial activities towards different microorganisms.

Synthesis and antimicrobial activity of some new isonicotinoylamino acid and dipeptide derivatives.

The synthesis of a series of isonicotinoylamino acids (II-XI) and some of their corresponding methyl esters (XII-XVIII), hydrazides (XXI-XXVI), dipeptide methyl esters (XXVII-XLII), the di- and tri-glycine peptides (XIX-XX) is described. Sixteen of various isonicotinoylamino acid and dipeptide derivatives were found to possess specific antimicrobial activities towards different microorganisms.

Biologically active halophthaloylpeptides. I. Synthesis of tetrachlorophthaloylamino acids and dipeptide derivatives.

The synthesis of a series of tetrachlorophthaloylamino acids and some of the corresponding methyl esters is described. Coupling of tetrachlorophthaloylamino acids with amino acid methyl esters by the N,N'-dicyclohexylcarbodiimide method yielded the desired tetrachlorophthaloyldipeptide methyl esters. All of the synthesized tetrachlorophthaloylamino acids, esters and some dipeptide methyl esters were found to be active against a number of microorganisms.

Synthesis of some 3-hydroxynaphthalene-2-carbonylamino acid and dipeptide derivatives.

Synthesis of a series of 3-hydroxynaphthalene-2-carbonylamino acid methyl esters (II-XI) and some of their corresponding hydrazides (XII-XXI), dipeptide methyl esters (XXII-XXXV) and dipeptide hydrazides (XXXVI-XXXIX) is described. 3-Hydroxynaphthalene-2-CO-L-Tyr-N2H3 (XX) and the corresponding L-Val-L-Ala-N2H3 (XXXVI) were found to be active against a number of micro-organisms.

Synthesis of some 2- and 4-methoxyacetylaminobenzenesulphonylamino acid derivatives and their antimicrobial activity.

The synthesis of a series of 3-acetylamino-4-methoxy-,2-acetylamino-4-methoxy- and 2-methoxy-5-acetylaminobenzenesulphonylamino acids, methyl esters, hydrazides and dipeptide methyl esters (IV-LXI) is described. Some o-, m- and p-anisidine and 2-aminopyridine derivatives have also been prepared by analogous procedure. Twenty of various by substituted acetylaminomethoxybenzenesulphonylamino acid and dipeptide derivatives were found to possess specific antimicrobial activities towards different microorganisms.

Synthesis and biological activity of some new 2-(aminoacyl- and dipeptidyl-)aminopyrazine derivatives.

Synthesis of some new 2-(N-tosyl- or N-phthalylaminoacyl or free aminoacyl or N-tosyldipeptidyl- or N-phthalyldipeptidyl)aminopyrazine derivatives (II-XXX) are described. All 2-(aminoacyl)aminopyrazines (XIV-XVIII) have been found to be biologically active against a number of microorganism.

Synthesis and biological activity of some new substituted aminoacyl-carbazole derivatives. Part II.

3-Nitro-9-(N-phthalyl- and N-tosylaminoacyl)carbazoles (II-XI) have been synthesized by the action of 3-nitro-9H-carbazole (I) on N-phthalyl- or N-tosylamino acid in THF-Et3N medium using the DCC method. Treatment of the 3-nitro derivatives (II-XI) with Sn/HCl gave the corresponding 3-amino-9-(N-phthalyl- or N-tosylaminoacyl)carbazoles (XII-XIX). Hydrazinolysis of the N-phthalylcarbazoles derivatives (III-VII) in ethanol gave the corresponding 3-nitro-9-(aminoacyl) carbazoles (XX-XXIII). Compounds (II-XI and XXI, XXII) were found to be active against some microorganisms.

Synthesis and biological activity of some new 3,6-dinitro-1:8-naphthaloyl- and 3,6-diamino-1:8-naphthaloylamino acids and dipeptide derivatives.

Synthesis of a series of 3,6-dinitro-1:8-naphthaloylamino acids (II-IX) and some of their corresponding methyl esters (X-XVI) and 3,6-diamino-1:8-naphthaloylamino acid derivatives (XXIX-XXXVI) is described. Coupling of 3,6-dinitro-1:8-naphthaloylamino acids with amino acid methyl ester hydrochlorides in dioxane-DMF-Et3N medium using DCC method furnishes the desired 3,6-dinitro-1:8-naphthaloyldipeptide methyl esters (XVII-XXVIII). Most of the synthesized 3,6-dinitro-1:8-naphthaloylamino acids, esters and dipeptide derivatives (compounds III-VI, XI-XV, XVII, XIX-XXI, XXIII and XXV) and 3,6-diamino-1:8-naphthaloylamino acid derivatives (XXIX-XXXV) were found to be active against a number of microorganisms.

Synthesis of some biologically active substituted thiazole and thiazoline-amino acid derivatives. Part I.

Synthesis of a series of N-(2-acetylaminothiazole-5-sulphonyl) amino acids (II-VI) and some of their corresponding methyl esters (VII-XI) is described. Coupling of N-tosyl-or N-phthalylamino acid with 2-amino-2-thiazoline using the DCC method furnishes 2-(N-tosyl- or N-phthalylamino acyl) amino-2-thiazoline (XII-XXI). Hydrazinolysis of 2-(N-Pht-L-Phe or N-Pht-L-Ala) amino-2-thiazoline in ethanol afforded 2-(L-Phe or L-Ala) amino-2-thiazoline (XXII and XXIII) respectively. Synthesis of the dipeptide 2-(N-Tos-L-Val-L-Leu) amino-2-thiazoline (XXIV) has been achieved employing the azide method. Sixteen thiazole- and thiazoline-amino acid derivatives were found to be active against a number of microorganisms.