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Extensive Study of Rhodanine-Arylamine-Based Chromophores: Consolidated Optical, DFT/TD-DFT and Non-Linear Optical Properties
摘要： Three push-pull rhodanine-arylamine based D-π-A dyes (2a-2c) are prepared to study the effect of donor on electronic, linear and nonlinear optical properties. The dyes, 2a,2b and 2c have a vinyl spacer conjugated with triphenylamine, julolidine, and carbazole donors respectively, with a methoxy group and rhodanine-3-acetic acid. The dyes exhibited solvent dependent absorption-emission up to the red region with large Stokes shifts (2a = 77-130 nm). This dyes possess charge transfer characteristics as established by transition dipole moment (μeg), dipole moment ratio (μe/μg), Generalised Mulliken-Hush analysis, and electron distribution (DFT). The non-linear optical study revealed that quadratic hyperpolarizability (μβCT) are 1098.9 (2a), 515.0 (2b) and 339.6 x 10-48 e.s.u. (2c) depending on donor strength. The intrinsic hyperpolarizabilities fall below βint0 = 10-3/2 limit i.e. less than unity. Solvatochromic two-level model is used to study the trends in two photon cross-section (σ2PA). The dye 2a exhibited high σ2PA, 216 GM (λmax 485 nm and 564 nm). The dyes 2a and 2c with analogue dye 3a show reverse saturable absorption (RSA) therefore, show positive third order nonlinear absorption coefficient, β and reasonable values of third order nonlinear susceptibility and high laser damage threshold. The Re χ(3) factors are responsible for the high values of χ(3) in the range of 0.77 to 8.09 x 10-12 e.s.u. Therefore, this material would serve as good candidate in the photonic application.
关键词： hyperpolarizability,Z scan,Arylamine donors,σ2PA,LDT
更新于2025-09-23 15:23:52
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Rb <sub/>10</sub> Zn <sub/>4</sub> Sn <sub/>4</sub> S <sub/>17</sub> : A Chalcogenide with Large Laser Damage Threshold Improved from the Mn-Based Analogue
摘要： In the military and civilian fields, with the development of new technologies, high-powered nonlinear optical (NLO) crystals demonstrate broad application prospects. For purposes of designing a better NLO material, a new chalcogenide Rb10Zn4Sn4S17 was successfully designed with a high temperature solid-state method on the basis of previously reported compound Sr3MnSn2S8. The experimental results indicate that Rb10Zn4Sn4S17 possesses a prominent band gap of 3.59 eV, compared with the laser damage threshold (LDT) of Sr3MnSn2S8 (3 times that of AgGaS2); Rb10Zn4Sn4S17 shows an outstanding LDT about 5 times that of AgGaS2. Meanwhile, it has an ideal second harmonic generation (SHG) response approximately 0.7 times that of AgGaS2.
关键词： second harmonic generation (SHG),laser damage threshold (LDT),chalcogenide,nonlinear optical (NLO) crystals
更新于2025-09-19 17:13:59
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Benzothiazole pyrazole containing emissive azo dyes decorated with ESIPT core: Linear and non linear optical properties, Z scan, optical limiting, laser damage threshold with comparative DFT studies
摘要： Positional isomers of "benzothiazoles-pyrazole based azo dyes containing separate with ESIPT core" are analyzed for their "linear and non-linear optical (NLO)" properties. Dyes are emissive in ACN having Stokes shift in the range of 75 nm. Spectroscopic properties are further utilized to calculate band gap by CV. Band gap obtained by DFT and cyclic voltammetry (CV) are in good agreement with each other. Vertical excitation in six different functionals is compared with experimental absorption maxima. Non-linear absorptive coef?cient (b), nonlinear refractive index (?2), third-order non-linear optical suscep- tibility (c3) and optical limiting (OL) in acetone, ethanol and DMSO are obtained using Z-scan technique and results are appreciable than previously reported dyes. Satisfactory laser damage threshold (LDT) values are in the range of 7.9e9.7 (cid:1) 1013 W/m2. TGA study indicates that these compounds are useful in several high-temperature processes in the construction of electronic and optical devices. The geometry of the dyes are optimized at "B3LYP/6-311 t G (d,p) level". "Molecular Electrostatic Potential" (MEP), "Frontier Molecular Orbitals" (FMO) are presented using "Density Functional Theory (DFT)" to gain structural insights. Relatively new electrophilicity descriptor- "Hyperhardness" for both the molecules are calculated which suggests the stability of molecules. Global hybrid (GH) functional (B3LYP, BHandHLYP) and range separated hybrid (RSH) (CAM-B3LYP, uB97, uB97X, and uB97XD) functional are used to calculate linear and NLO properties. uB97 is a more suitable functional observed for determining bo and g. Direct relation in-between "dipole moment" (m) and "linear polarizability" (a) is also presented. These dyes can emerge as attractive NLOphores in optoelectronic applications.
关键词： ESIPT,NLO,Z-scan,LDT,DFT,Emissive azo dyes,Benzothiazole-pyrazole
更新于2025-09-11 14:15:04
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Growth, Optical, Thermal, Mechanical, Laser Damage Threshold and Electrical Polarizability of Cadmium Chloride Doped l-Alanine (LACC) Single Crystal for Optoelectronic Applications
摘要： L-Alanine doped with cadmium chloride crystal was grown by slow evaporation technique in an optimum condition using de-ionized water as solvent. Single crystal x-ray diffraction analysis was carried out to con?rm the unit cell parameters and cell volume. The presence of amine vibrations and carboxylic acid vibrations af?rm the presence of L-alanine in grown material by Fourier transform infrared (FT-IR) analysis. The ultraviolet visible near-infrared region (UV–Vis-NIR) spectrum revealed that the grown crystal has a lower cut-off wavelength at 246 nm and has high transmission in the entire visible region. Further, energy gap and the refractive index of the crystal were also calculated. Thermo-gravimetric (TG) and differential thermal analysis (DTA) were carried out, and it is estimated that the material is thermally stable up to 233°C and the melting point of the crystal was found to be 298°C. The mechanical strength of the material is estimated for various loads using Vicker’s microhardness and it reveals that material belongs to a soft material category. The electrical polarizability was calculated using known values such as valence electron, molecular weight, energy gap and density of the material. Z-scan technique for nonlinear studies was carried out on a LACC crystal to determine the third order nonlinear absorption (b), nonlinear refractive index (n2) and third order nonlinear susceptibility (v(3)) using continuous wave Nd: YAG laser of 532 nm. Grown crystal shows that the material is very much suitable for second harmonic generation for frequency conversion applications.
关键词： electrical polarizability,LDT,Z-scan technique,X-ray diffraction,FT-IR,microhardness,TG-DTA
更新于2025-09-11 14:15:04
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Structural, Optical, Mechanical and Laser Damage Threshold Studies on an active Nonlinear Optical Material: Potassium Thiourea Bromide (KTB) in a Novel Crystal System
摘要： The enhancement of optical transparency, crystalline perfection, laser damage threshold values and principally, mechanical strength of thiourea doped potassium bromide crystals grown under slow evaporation solution growth technique were assessed. The validation and morphology were done by X-ray diffraction analysis. The sample KTB crystallized in orthorhombic system is unique and novel. The vibrational range in the FT-IR affirmed the functional groups present in the title compound. The energy gap Eg found to be 4.12eV with broad transparency window between 300.600nm to 1100nm. Second harmonic studies manifest the suitability of the crystal for frequency conversion and doubling applications. The positive photo conducting nature of the material aspires that the sample would be more electrically conductive on the absorption of electromagnetic radiation. The laser damage threshold value indicates the aptness of the sample to confront against high power intensities. The elastic(C11), plastic, fracture traits(Kc) along with the yield strength(σv) and brittleness index(Bi) were calculated and reported for the first time under orthorhombic system. The result also evident appreciable mechanical strength of the crystal, as it holds cardinal importance in technological applications.
关键词： Crystal growth,Mechanical properties,Non linear optical material,Characterization,LDT,Photoconductivity
更新于2025-09-11 14:15:04