Third-order NLO Properties Research Articles

Crystal growth and characterization of Benzimidazolium salicylate single crystal for nonlinear optical studies and antibacterial activity

Organic non-linear optical Benzimidazolium salicylate (BISA) single crystals have been harvested from methanol solution by slow evaporation method. The grown crystals belong to the monoclinic crystal system with space group P21/c. Good crystalline nature of grown BISA crystal was confirmed by PXRD. The FTIR spectrum analysis affirms the presence of functional groups in BISA crystal. From the UV‒Vis-Absorption spectrum, the lower cut-off wavelength (356 nm) and its energy band gap and linear refractive index were calculated. Luminescence spectrum was recorded to explore the emission peak at 426 nm. The mechanical strength of BISA crystal was determined by Vickers microhardness tester and mechanical parameters like C11, Hk, Kc, and Bi were calculated for the first time. Dielectric properties of grown crystals were systematically investigated for different temperatures. Further, electronic polarizability (α) were calculated using Penn analysis and Clausius‒Mossotti equation. Z‒scan measurement was taken to explore the third-order NLO properties of BISA crystal. For the first attempt, the BISA crystals were tested against five human pathogenic bacterial, i.e. Bacillus cereus, Staphylococcus aureus, Shigella flexneri, Vibrio cholerae, and Klebsiella pneumoniae. Existing results established that Benzimidazolium salicylate crystals might find useful applications in nonlinear optics and antimicrobial field.

Third order non linear optical properties of novel furan based organic crystal

A crystal for potential nonlinear optical applications, namely 1-(furan-2-yl)-3-(3, 4, 5-trimethoxyphenyl) prop-2-en-1-one (FT3MP), has been synthesized using slow evaporation technique. The functional groups present in the compound have been studied with Fourier transform infrared spectroscopy. The Z-scan technique with the single beam was used to examine the third-order NLO properties of the crystal. The measured nonlinear optical absorption coefficient (β), nonlinear refractive index (n2) and the third order nonlinear optical susceptibility (χ(3)) of FT3MP suggest that the crystal is good for possible photonic applications.

New quinacridone derivatives: Synthesis, photophysical and third-order nonlinear optical properties

A series of quinacridone third-order nonlinear optical chromophores containing phenyl, 4-methoxyphenyl and N,N-bis(4-methoxyphenyl)aniline groups were designed and synthesized. The optical properties, electrical properties, theoretical calculations and Z-Scan of the compounds were measured and analyzed to investigate the relationship between structure and third-order NLO properties. The experimental results showed that the introduction of electron-donating groups at the N-position of quinacridone decreases the energy gap (Egap) between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of the molecule, and promotes intramolecular charge transfer (ICT). Quinacridone derivatives containing N, N-bis (4-methoxyphenyl) aniline have good third-order nonlinear optical properties, with the nonlinear absorption coefficient (β) value of 1.4319 × 10−13 and the second-order superpolarizability (γ) of 2.6849 × 10−33 esu.

Synthesis and characterization of GO doped bio-resource based composites for NLO and multifaceted applications

The objective of the present work is to synthesize three different types of cardanol based benzoxazines such as cardanol-{1,4-bis(4-aminophenoxy)ethane}benzoxazine (CBAE2Bz), cardanol-{1,4-bis(4-aminophenoxy)butane} benzoxazine (CBAE4Bz) and cardanol-{1,4-bis(4-aminophenoxy)octane}benzoxazine (CBAE8Bz) by varying aliphatic ether link chain length through solventless method. The benzoxazines obtained with varying chain length were converted in to three different types of composites using paraphenylenediamine (PPDA) functionalized gaphene oxide (f-GO) as nano-reinforcement with varying weight percentage and were characterized by different analytical techniques. The molecular structure of the monomers was confirmed from Fourier transform infrared (FTIR) spectroscopy, 1HNMR, 13C NMR and MALDI mass. Data obtained from thermal studies infer that the prepared composites possess good thermal stability and enhanced values of Tg with respect to weight percent of functionalized graphene oxide content. However, the values of thermal stability, Tg, dielectric constant and dielectric loss were marginally decreased with respect to increase in length of the spacer aliphatic chain. The SEM and TEM studies confirm the homogeneous dispersion and single layer thickness of graphene sheet, respectively. The feasibility of usage of f-GO/PCAE2Bz composite in both gram positive bacteria (Bacillus subtilis, Staphylococcus aureus) and gram negative bacteria (Pseudomonas aeruginosa, Escherichia coli) environments were checked and the results obtained were discussed. Further, third-order NLO properties of open and closed aperture Z–scan results conclude that GO doped bio-resource based composites exhibit saturable absorption and self-defocusing type optical non-linearity. The third-order NLO susceptibility (χ3) of GO doped bio-resource based composites are increased with respect to quantity of reinforcement of GO to bio-based polymer. The maximum value of 1.03X 10−4 esu was observed and this nonlinearity is thermal in nature. Thus, the prepared composites may find wide range of applications in diverse surrounding conditions.

Two new isolated Zn-ε-Keggin clusters modified by conjugated organic ligands with decent electrocatalytic and third-order NLO properties.

Two new bifunctional isolated hybrid compounds, [ε-PMoV8MoVI4O37(OH)3Zn4][iql]4·6H2O (1) and [ε-PMoV8MoVI4O38(OH)2Zn4][bipy]3[(CH3COO)(bipy)2Zn]·2H2O (2) (where iql = isoquinoline and bipy = 2,2'-bipyridine), based on Zn-ε-Keggin were successfully synthesized by self-assembly under hydrothermal conditions. It is interesting to note that acetate in 2 acted as a linker connecting the ε-Keggin anion with the one Zn atom (Zn5) and enabled the ε-Keggin anion to coordinate with more bipy ligands, culminating with a larger isolated system, which is the first reported isolated cluster of Zn5PMo12. Meanwhile, compounds 1-2 show great electrochemical behaviors and excellent electrocatalytic activity for the degradation of NaNO2. In addition, compound 2 displays better third-order NLO performance than 1 due to the presence of more conjugated rings, with a TPA cross section (σ) of 1819 GM, which suggests that compound 2 has the potential to function as a bifunctional material with tremendous prospects.

Auto-controlled fabrication of a metal-porphyrin framework thin film with tunable optical limiting effects.

Metal–organic frameworks (MOFs) with third-order nonlinear optical (NLO) properties are still in their infancy but are very important. In this work, we first develop a layer by layer autoarm immersion method for preparing porphyrin-based MOF (PIZA-1) thin films with third-order NLO properties. By precisely controlling the thickness, the nonlinear absorption of PIZA-1 thin films can be switched continuously between reverse saturable absorption (RSA) and saturable absorption (SA) by using the Z-scan technique. In addition, the optical limiting effect could be further optimized by loading C60 in the pores of the PIZA-1 thin film. These findings not only open a new route for the exploitation of third-order NLO thin film materials, but also offer an insightful understanding of porphyrin-based MOF thin films for future broad practical applications.

Correlation between structural studies and third-order NLO properties of three new semi-organic compounds

Correlation between structural studies and third-order NLO properties of three new semi-organic compounds

Novel blue-green emitting NLOphoric triphenylamine-imidazole based donor-π-acceptor compound: Solvatochromism, DFT, TD-DFT and non-linear optical studies.

Novel Donor (D)-π-Acceptor (A) NLOphoric triphenylamine-imidazole based dye 9 was designed, synthesized, and confirmed by Mass, 13C NMR, and 1H NMR analysis. Photophysical properties of 9 were studied in solvents of different polarities and compared with analogues compounds 7 and 8. Phenonthroline acceptor based dye 9 shows highly bathochromic shifted absorption and emission compared to dyes 7 and 8. Positive solvatochromism was noticed in 7, 8, and 9 which was supported by the linear (i.e. Lippert-Mataga and Mac-Rae polarity functions) and multi-linear (i.e. Kamlet-Taft and Catalan parameters) analysis. Moreover, solvent polarizability (dSP) and solvent dipolarity (CSdP) are the major factors responsible for red shift in absorption as well as in emission spectra. Charge transfer descriptors as well as the polarity graphs are in good relation with Generalized Mulliken-Hush (GMH) parameters. NLO properties of 7, 8, and 9 were studied by using solvatochromic and computational methods. The static first hyperpolarizability (β0) and relevant microscopic parameters (μ,α0,α,β,γ) were determined using DFT with B3LYP, BHHLYP, and CAM-B3LYP functionals. Third-order NLO properties of nitrogen containing phenanthroline based compound 9 were observed to be several times higher than those of the compounds 7 and 8, justify the design approach.

Effect of Cu2+ ion on single crystal of nonlinear optical material (glycinium oxalate)

Single crystals of pure and Cu2+doped glycinium oxalate of dimensions 18 × 10 × 2 mm3 and 10 × 7 × 2 mm3 were grown by the solvent evaporation technique, respectively. Influences of Cu2+ ions on the crystalline quality of glycinium oxalate (GOX) crystal were studied. The grown pure and doped crystals were characterized by using powder X-ray diffraction, FT-IR, and FT-Raman techniques. UV–Vis–NIR spectra of GOX and Cu2+ doped GOX single crystals had transparency in the entire visible region with cut off wavelengths, 257 nm and 265 nm, respectively. Mechanical properties of pure and doped crystals were studied using Vicker’s micro-hardness test. The presence of transition metal ion has been confirmed by energy dispersive X-ray spectroscopy (EDAX) and EPR analyses. The g-value (2.4899) was calculated from EPR analysis. The TGA/DTA analysis was performed to find the thermal stability of samples. The dielectric behavior of pure and doped crystal have been reported from 102 to 106 Hz. The third-order NLO properties such as nonlinear absorption coefficient (β), third-order nonlinear susceptibility (χ(3)) and nonlinear refractive indices (n2) of pure and doped crystal were estimated in the order of 10−6 esu.

Effect of nano fillers on electrical, mechanical, fluorescent and third order non linear optical properties of PVA

This paper explores the preparation of TiO2, MoO3 nanoparticles and PVA/(x)TiO2(15−x) MoO3 nanocomposites for filling concentration x = 0, 1, 5, 7.5, 10, 14 and 15 wt% via solution casting method. The XRD spectra of prepared samples confirm the formation of nanocomposites based on the observation of the peaks representing PVA and TiO2, MoO3 nanoparticles. The aforementioned reconnoitres the crystalline parameters specifying a high percentage crystallinity for x = 10 wt% filling concentration. The structural confirmations of nanocomposites are done using FTIR spectroscopy. The UV-Vis studies also reflects the same trend of decreasing energy gap for x = 10 wt% filling concentration. This surveillance is due to the interaction of added dopants with the OH group of host PVA. IV studies spectacles a high conductivity and low resistance for x = 10 wt% optimum filling concentration. The UTM explores the high tensile strength and Young’s modulus for x = 10 wt% filling concentration. The surface morphological studies determined by means of AFM shows average roughness of 125.3 nm. Photoluminescence studies gives an emission band at 390 nm corresponds to the surface trap induced effects and intense emission band at 680 nm resemble the electron hole recombination of TiO2 and MoO3 nanoparticles. AC conductivity shows that the conductivity increases for different doping concentrations with the rise in frequency. The frequency dependent dielectric constants with various doping concentrations of the prepared nanocomposites have been recorded. Using Z-scan technique the sign and magnitude of the third-order NLO properties of prepared nanocomposites were studied. From closed and open aperture Z-scan statistics it is perceived that the material exhibit strong two-photon absorption (2PA) with the nonlinear absorption (NLA) coefficients (β), nonlinear refractive index (NRI) and third order Non-linear optical susceptibility (χ3).

New Coumarin-benzoxazole derivatives: Synthesis, photophysical and NLO properties

In this work, a series of novel D-π-A structure coumarin-benzoxazole derivatives have been synthesized. The third-order NLO properties of the coumarin derivatives in DMSO are investigated by Z-scan measurement, and the photophysical properties of the compounds are studied through experimental and theoretical calculation methods. The results showed that the introducing specific functional groups at multiple active sites of coumarin reduced the π-π intermolecular stacking, while the formation of push-pull structure decreased E-gap of entire molecule. The excellent third-order NLO responses based on chromophore 4c with maximum nonlinear absorptive coefficients is 50.64 × 10−13 esu and the largest second-order NLO hyperpolarizability is 7.12 × 10−30 esu. Experimental results have also been confirmed through DFT, TDDFT and ZINDO calculations. Our results indicate that the coumarin fluorescent dyes are promising candidate materials for NLO applications.

Doping effect of urea on growth, spectral, thermal, mechanical, electrical, nonlinear and optical studies of Sr(HCOO)2·2H2O crystal: enhanced third-order NLO properties with a high laser-induced damage threshold

Pure and urea doped (with 3 different concentrations, viz. 0.005, 0.05, and 0.1 M) strontium formate dihydrate (SFD, Sr(HCOO)2·2H2O) single crystals were grown from aqueous solutions by using slow solvent evaporation technique. In order to understand the effect of urea doping on the structural, chemical, thermal, morphological, optical properties of SFD crystals, the grown crystals were characterized by carrying out CHN analysis, powder X-ray diffraction, high resolution X-ray diffraction, Fourier transform infrared spectral, thermogravimetric, UV–Vis–NIR spectral, photoluminescence spectral, second harmonic generation efficiency, and Z-scan measurements. The results obtained indicate that the urea molecule have entered into the SFD crystal matrix and has improved the crystallinity. Also, the results indicate that urea doping significantly tunes the optical and thermal properties without significantly distorting the crystal structure of SFD crystal. The laser damage threshold (LDT) energy for the grown crystal has been measured by using a Q-switched Nd:YAG laser as a source in single-shot mode (1064 nm, 10 Hz, 420 mJ). The result of laser damage threshold (LDT) energy indicates that grown title crystal has excellent resistance to laser radiation than those of some known inorganic NLO materials. Its third-order nonlinear optical properties were investigated by Z-scan technique and proved that the grown crystal possesses two-photon absorptions (TPA) and the self-defocusing effect.

A pair of new chiral polyoxovanadates with decent NLO properties.

Two pure enantiomers of polyoxovanadate clusters [(l-/d-C4O6H2)2V4O8]·2C6N2H18 (abbreviated as 1-L and 1-D) have been synthesized by a two-step method. During the two-step synthesis process, we first carried out the solvothermal synthesis and then evaporated the solvent, ending up with orange-yellow crystals. The unique chiral architectures are built up by a single chiral ligand (tartaric acid) and polyoxovanadium. The chiralities of the products were confirmed by circular dichroism (CD) spectra. Due to the presence of protonated free tetramethyl ethylenediamine (TMEDA) cations, the adjacent clusters and TMEDA cations can be connected by hydrogen-bonding interactions. The {V4} cluster linked adjacent clusters via hydrogen bonds to form a 3D supramolecular network. The open aperture Z-scan spectra of two compounds show that molecular TPA cross-section σ of 1-L and 1-D are 1412 and 1094 GM, respectively, which illustrate that they feature decent third-order NLO properties and may have great potential applications as NLO materials.

Bulk crystal growth, spectral, optical, thermal, electrical and third-order NLO properties of benzylidene malononitrile derivative single crystal: a promising material for nonlinear optical device applications

Bulk organic intramolecular charge transfer nonlinear optical single crystal of 2-(2,4-dimethoxybenzylidene) malononitrile (DMM) with the sizes of 24 × 18 × 13 mm3 have been successfully grown by slow evaporation solution growth technique at 35 °C using acetone as the solvent. The lattice parameters of the grown DMM crystal was evaluated by single crystal X-ray diffraction analysis. The optical transmittance (T) data was taken from the well-polished crystal of DMM, and cut-off wavelength (λ = 483 nm) was identified by UV–Vis spectral studies. Thermal stability and melting point (145.78 °C) were studied with TGA–DSC analysis. The low value of the dielectric constant (er) of DMM suggests that the crystal can be used in the microelectronics industry. The laser-induced damage threshold experiment shows that the grown DMM bulk crystal possess an excellent resistance to laser radiation with a high threshold up to 1.75 GW/cm2, much larger than those of several known organic and inorganic NLO materials. The DMM crystal exhibits positive optical non-linearity and reverse saturation absorption. It also exhibited a nonlinear refractive index (n2) in the order of 10−11 m2/W, a nonlinear absorption coefficient (β) in the order of 10−5 m/W, third order non-linear susceptibility (χ(3)) in the order of 10−5 esu and a second-order molecular hyperpolarizability (γ) in the order of 10−33 esu. All the above results indicate that DMM has a potential application as a useful NLO candidate.

Third-order NLO properties of ultrathin films containing cationic phthalocyanine and Keggin polyoxometalates fabricated using layer-by-layer deposition from aqueous solution

Third-order optical nonlinearities of ultrathin films derived from cationic phthalocyanine and Keggin polyoxometalates can be well tuned and enhanced.

Structural, optical, electrical properties of new hybrid organic–inorganic NLO single crystal: bis(1H-benzotriazole) hexaaqua-zinc bis(sulfate) tetrahydrate (BZS)

A new hybrid organic–inorganic nonlinear (NLO) single crystal, Bis(1H-benzotriazole) hexaaqua-zinc bis(sulfate) tetrahydrate (BZS), has been successfully synthesized and the single crystals were grown by slow evaporation solution growth technique (SESG) using Millipore water as a solvent. The structure of the BZS crystal was solved and refined by single-crystal X-ray diffraction and demonstrates that the grown crystals belong to a triclinic system with the space group P-1. The asymmetric part of the titled compound contains isolated organic cation (C6H6N3)2, metallic cation [Zn(H2O)6]2+, sulfate anion (SO4)2− and free H2O molecules. The interplay between the wide number of intermolecular interaction such as O–H···O, N–H···O, C–H···O and π–π stacking interactions were discussed. The optical transmittance spectrum shows that the crystal is excellent transmittance in the entire Vis–NIR region with the cutoff wavelength at 345 nm. The presences of expected functional groups were identified by Fourier transform infrared spectroscopy. The dielectric measurements were carried out at different temperature in the frequency range 100 Hz–5MHz. Furthermore, the studies of its third-order NLO properties using a Z-scan technique demonstrate that the BZS crystal possesses a strong reverse saturable absorption (RSA) and the self-focusing (SF) nature with large second order hyperpolarizability (γ = 6.24 × 10−34 esu). All the results indicate that BZS crystal might be the potential candidate for the third-order NLO applications.

Enhanced nonlinear optical absorption and optical limiting properties of superparamagnetic spinel zinc ferrite decorated reduced graphene oxide nanostructures

Nonlinear absorption and optical limiting properties of ZnFe2O4-rGO magnetic nanostructures was investigated by the Z-scan technique using Q-switched Nd:YAG laser (5ns, 532nm, 10Hz) as an excitation source. Excited state absorption was the dominant process responsible for the observed nonlinearity in ZnFe2O4 decorated rGO which arises due to photo-generated charge carriers in the conduction band of zinc ferrite and increases in defects at the surface of rGO due to the incorporation of ZnFe2O4. The magnitude of the nonlinear absorption co-efficient was found to be in the order of 10−10m/W. A noteworthy enhancement in the third-order NLO properties in ZnFe2O4-(15wt%) rGO with those of individual counter parts and well known graphene composites was reported. Role of induced defects states (sp3) arising from the functionalization of rGO in the enhancement of NLO response was explained through Raman studies. Earlier incorporation and distribution of ZnFe2O4 upon GO through one-step hydrothermal method was analyzed by XRD and FTIR. Formation of (nanospheres/nanospindles) ZnFe2O4 along with reduction of graphene oxide was confirmed through TEM analysis. VSM studies showed zinc ferrite decorated rGO posseses superparamagnetic behavior. The tuning of nonlinear optical and magnetic behavior with variation in the content of spinel ferrites upon reduced graphene oxide provides an easy way to attain tunable properties which are exceedingly required in both optoelectronics and photothermal therapy applications.

Zwitterionic Cyanine–Cyanine Salt: Structure and Optical Properties

Cyanines with long conjugation length such as heptamethines are well known to have strong intramolecular and/or intermolecular interactions (i.e., ion paring and aggregation), which can affect their structures (i.e., symmetry breaking) and optical properties remarkably. In this paper, we report a covalently linked complementary cyanine complex of cationic and anionic heptamethines forming a highly polarizable zwitterionic cyanine–cyanine salt. The effect of the modification was studied in detail on both its electronic structure and its optical properties. This novel zwitterionic salt was found to exhibit a decreased ion-pairing-induced charge localization but with an increased electronic coupling between the excited states of the cyanine cation and the anion, resulting in unusual optical properties compared to closely related noncovalent complementary cyanine salts. The dual-arm Z-scan technique was used to study their third-order NLO properties, suggesting the electronic coupling in such preorganized zwi...

Synthesis, spectral, theoretical calculations and optical properties performance of substituted-azobenzene dyes

This paper explores the synthesis, the structure characterisation and optical properties of two new azobenzene dyes. The obtained dyes were characterized by UV, 1H and 13C NMR. Their third-order NLO properties were measured using the third harmonic generation technique on thin films at 1064 nm. The electric dipole moment (μ), the polarizability (α) and the first hyperpolarizability (β) were calculated using the density functional B3LYP method with the lanl2dz basis set. Also, the Mulliken atomic charges and the Molecular electrostatic potential were investigated.

Synthesis, spectral, optical properties and theoretical calculations on schiff bases ligands containing o-tolidine

This paper explores the synthesis, structure characterization and optical properties of two new schiff bases. These compounds were obtained by condensation of o-tolidine with salicylaldehyde and cinnamaldehyde. The obtained ligands were characterized by UV, 1H and NMR. Their third-order NLO properties were measured using the third harmonic generation technique on thin films at 1064nm. The electric dipole moment (μ), the polarizability (α) and the first hyperpolarizability (β) were calculated using the density functional B3LYP method with the lanl2dz basis set. For the results, the title compound shows nonzero β value revealing second order NLO behaviour.