Nonlinear Optical Activity Research Articles

Effects of solvents on structure and energy of 6-amino-2-mercapto-3H-pyrimidin-4-one: A computational study

6-amino-2-mercapto-3H-pyrimidin-4-one (AMP) is a π-conjugated organic molecule extensively used as a semiconductor in many optoelectronic devices. The computational hybrid meta-generalized gradient Minnesota M06-2x, ωB97XD, and B3LYP functionals in conjunction with the correlation consistent polarized valence triplet zeta (cc-pVTZ) basis set and the moderate composite CBS-QB3 procedure were used with the aid of the Gaussian 09 program and the kinetic and statistical thermodynamical package (KiSThelP) in the temperature range 250–400 K to investigate the behavior of AMP in the gas phase, and in different polar (water, ethanol), and non-polar (dimethyl sulfoxide (DMSO), acetone)) solvents. Non-linear optical (NLO) characteristics and quantum chemical parameters were examined. Natural bond orbital analysis (NBO) was used to characterize the charge transfer of the electron density in the investigated compounds. The quality of the methods used was inspected and compared to give accurate results. The stability of AMP can be returned to the hyper conjugative interactions that leading to its nonlinear optical activity. Also, the charge delocalization was analyzed using natural bond orbital technique. The molecular electrostatic potential surfaces (MEPS) plots have been generated. The rate coefficients of tautomerization processes (kuni, in s−1) were calculated from the transition state theory (TST) and unimolecular Rice-Ramsperger-Kassel-Marcus (RRKM) methods. The results indicate comparable chemical rates obtained from TST and RRKM. In addition, positive temperature dependencies were located for all channels and a high dominance of transferring H-atom from the external N-atom to the S-atom (R3 reaction) during the applied temperature range which can return to its lower activation energy. This study is the first stone in studying AMP under different conditions such as the atmosphere, combustion conditions and as a nano catalyst.

Nonlinear optical activity of polymer materials doped with quinoxaline-based chromophores containing TBDPSO groups

Nonlinear optical (NLO) activity of polymer materials doped with 30 and 40 wt% load of two novel thermally stable quinoxaline-based chromophores with bulky TBDPSO groups in donor fragments was studied by second harmonic generation technique. Poled thin polymer film with chromophore B containing five various bulky substituents demonstrates low d33 values (14–19 pm/V). Oppositely, composite material with 30 wt% load of chromophore A, which does not contain bulky substituents in acceptor moiety, have shown enhanced NLO activity (up to 51 pm/V).

An experimental and computational exploration on noncovalent interactions, spectroscopic and nonlinear optical properties of novel creatininium cyanoacetate single crystal

A novel creatininium cyanoacetate (CCA) single crystal is synthesized by the slow evaporation technique and characterized by various experimental techniques such as FT-IR, FT-Raman and UV–visible spectral methods. Similar techniques are also investigated by the computational methods using Gaussian 09 software. The structural parameters, natural bond orbital (NBO), frontier molecular orbital (FMO), molecular electrostatic potential (MEP) and nonlinear optical (NLO) investigations are performed utilizing the DFT method with B3LYP/6-311G(d,p) basis set. The polarizable continuum model (PCM) has been used to identify the effect of various solvents (DMSO, ethanol, methanol, water) on the energy gap, excitation and NLO properties of CCA molecule. Fukui analysis is performed to identify the sites prone to nucleophilic and electrophilic attacks. Different topological methods including electron localization function (ELF), localized orbital locator (LOL), independent gradient model (IGM) and interaction region indicator (IRI) has been performed to quantify the noncovalent interaction and to analyse the weak interaction region. The UV–visible analysis indicates that the CCA crystal was optically transparent and has lower cut-off wavelength. The hole-electron analysis is performed to identify the characteristics of six excitations. The third-order NLO activity of the CCA compound is performed using the Z-scan technique and is compared with some related NLO materials. The substantial NLO response suggests that the CCA molecule can be significant for its utilization in advanced NLO applications.

Growth and improved properties of single crystal α-LiIO3 doped with amino acids

In this study, the effect of doping the amino acids L-arginine and L-nitroarginine on α-LiIO3 single crystal were presented. Bulk crystals were grown both from solutions doped with L-arginine and L-nitroarginine and from pure solution of α-LiIO3.When doped with L-arginine and L-nitroarginine the optical quality of the crystals was improved and growth rate was increased. These grown crystals were studied by single-crystal X-ray diffraction, IR and UV–Vis spectroscopy, Vickers microhardness, diffuse reflection, and second harmonic generation methods. Studies of microhardness and nonlinear optical activity showed that the properties of α-LiIO3 crystals were improved in the presence of L-arginine and L-nitroarginine. UV–Vis transmittance was improved in the presence of L-arginine (range 370–800 nm) and L-nitroarginine (range 290–370 nm). The second harmonic generation activity of the crystals α-LiIO3 grown with L-arginine (1.16 times) and L-nitroarginine (1.18 times) dopants is higher than that of pure α-LiIO3. The energy of the band gap increases by 1.2 times in the case of arginine dopants, and it decreases by 1.37 times in the case of the nitroarginine dopants, compared to that for the pure α-LiIO3.

Crystal growth, structural, vibrational, spectroscopic studies of novelly synthesized NLO active melaminium sulfamate single crystal: Experimental and theoretical approach

Semi-organic nonlinear optical (NLO) melaminium sulfamate (MASA) single crystals were synthesized by slow evaporation method and analyzed by using X-ray diffraction, UV–vis, FT-IR and FT-Raman experiments. Single crystal X-ray diffraction (SXRD) analysis confirms that MASA crystal belongs to triclinic system with centrosymmetric space group P-1. The quantum chemical calculation were carried out using density functional theory (DFT) with B3LYP/6-31+G(d) basis set. The intermolecular interactions were deeply analyzed by NBO analysis. The molecule with intermolecular N-H⋯N and N-H⋯O hydrogen bonds show notable vibrational effect. The optical property of MASA was evaluated by UV–vis optical transmittance spectrum. Thermal stability of the grown crystal was performed by using TG-DTA analysis. The frontier molecular orbital analysis illustrates the charge transferred from sulfamate anion to melaminium cation. Hirshfeld and 2D fingerprint plot reveals the intermolecular N-H⋯O and N-H⋯N contacts of MASA molecule. The existence of various functional groups and vibrational modes are affirmed by Fourier transform infrared (FT-IR) and FT-Raman spectral analysis. Additionally, the molecular electrostatic potential (MESP) and topological analysis such as electron localization function (ELF), reduced density gradient(RDG), localized orbital locator(LOL) and atoms in molecule(AIM) have been used to predict the intermolecular interaction, especially the hydrogen bonds. The hydrogen atom from sulphamic acid was transferred to the melamine molecule giving the singly protonated melaminium cation. The outcome of SXRD, UV–visible, TG/DTA, HOMO–LUMO, NLO and Z-Scan values were compared with earlier reported compounds and amongst the analyzed compound MASA shows good NLO activity. The NLO activity of MASA was analyzed theoretically and experimentally by DFT and Z-scan method.

Nonlinear optical properties in chiral copper oxide nanosheets.

Chiral transition metal oxides (TMOs) are in the forefront of research as potential active materials in various optoelectronic applications. However, the nonlinear optical (NLO) properties of the chiral TMOs have not been fully understood. Here, several kinds of copper oxide nanosheets capped with different chiral amino acids are synthesized. Notably, we investigate the NLO activities of these materials, including broadband second harmonic generation and transformation of nonlinear optical properties from saturable absorption to reverse saturable absorption. This work will broaden the use of chiral TMO materials in nonlinear photonic devices.

Exploring linear and nonlinear optical behaviour of morpholine p-nitrophenol crystal: Computational and experimental analysis

Optically good quality morpholine p-nitrophenol (MPN) crystal was effectively grown from a slow evaporation technique. Unit cell parameters of MPN were estimated by single crystal X-ray diffraction and it crystallizes in the P21/c space group. The existence of several functional groups in MPN is established by FTIR analysis. UV–vis-NIR spectroscopy inspected the lower cut-off wavelength and band gap energy of MPN. A fluorescence spectral analysis of MPN was carried out. Experimental and computational calculations of nonlinear optical activity have been studied. The second harmonic generation of MPN is 1.9 times greater than the reference KDP material. Using the Z-scan approach, the grown crystal's third-order NLO susceptibility (χ3) was determined. The laser damage threshold of MPN crystal is studied and it is estimated as 5.12 GW/cm2. The highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO) and molecular tying-up explorations were executed. Ground state enhanced geometry and molecular electrostatic potential (MEP) were analysed.

Modeling, spectroscopic structural properties of platinum-II complexes of 2-((phenylimino)methyl)phenolate-based ligands and research of nonlinear optical, organic light emitting diode and solar cell performances

The hypothetical Pt(B1)2, Pt(B2)2 and Pt(B3)2 complexes were modeled. B1, B2 and B3 are Schiff bases, 2-((phenylimino)methyl)phenolate, 4-methyl-2-((phenylimino)methyl)phenolate and 4-nitro-2-((phenylimino)methyl)phenolate, respectively. The ground state structures of the complexes were computed at the DFT-B3LYP/6–31 G(d)/LANL2DZ level. From the characteristic bond lengths, bond angles, bond stretching frequencies and proton chemical shift values, the platinum environment geometry was found to be square plane. The nonlinear optical (NLO) activities of the complexes were investigated by calculating some nonlinear optical property parameters and NLO performance of Pt(B3)2 was found to be higher than other complexes. Organic light emitting diode (OLED) performances of the complexes were investigated and found that the all complexes could be suitable for the production of OLED-featured materials. The solar cell (SC) performances of the complexes were determined by considering the power conversion efficiency (PCE). it was suggested that the Pt(B3)2 complex might have the highest solar cell performance.

Wavelength-Dependent Nonlinear Optical Activities of Near-Infrared Boron-Dipyrromethene Derivatives

Near-infrared (NIR) organic dyes with strong ultrafast nonlinear optical (NLO) activities are important for various applications. However, the study of the wavelength-dependent NLO properties of NIR dyes is still ongoing. In this work, we present the first comparison of the NLO properties of two NIR boron-dipyrromethene (BODIPY) derivatives at different excitation wavelengths, in which strong electron-donating groups, namely 4-(N,N-dimethylamino)phenyl and 1-ethyl-1,2,3,4-tetrahydroquinoline groups, are connected through the BODIPY cores. Results obtained from Z-scan experiments show that the two BODIPY derivatives exhibit strong saturable absorption and large modulation depth when excited by femtosecond pulses at 800 nm. With 1300 nm excitation, both derivatives exhibit strong nonlinear refraction. In addition, the derivatives also display effective two-photon action cross-sections in the wavelength range of 1200–1600 nm. They are potentially excellent nonlinear optical materials. This comprehensive comparison of the NLO properties of BODIPY derivatives can suggest new possibilities for the design and development of NIR NLO materials.

Nonlinear optical response of silver trimer adsorbed para-aminobenzoic acid: A DFT study

The reported study is motivated by our previously done experimental demonstration of the optical limiting behavior of para-aminobenzoic acid and enhanced nonlinear optical responses of compounds with Ag3 nanoparticle complex. The present study is a theoretical insight into the nonlinear optical responses of para-aminobenzoic acid adsorbed with Ag3 trimer. The enhancement in the optical nonlinearity of the para-aminobenzoic acid after the adsorption of the silver trimer (Ag3) was accounted in the present study. The density functional theory was used to establish the occurrence of the intra and intermolecular charge transfer between the donor and acceptor moieties of the para-aminobenzoic acid and Ag3 trimer. The molecular electrostatic potential surface and inter-fragment charge transfer analysis were used to establish the donor nature of the Ag3 trimer, amino group, and acceptor of the carboxyl group. The absorption spectra and Fourier-transform infrared spectra were used to account for the electronic and vibrational modes. The value of first-order hyperpolarizability of para-aminobenzoic acid and Ag3 complex was observed to increase by six times that of para-aminobenzoic acid. The high value of first-order hyperpolarizability shows the potential nonlinear optical activity of para-aminobenzoic acid adsorbed with Ag3 trimer. The presented study forms a strong base for experimental demonstration of the nonlinear optical activity of the PABA and the silver nanoparticles and the experimental work will be done in the near future for the NLO responses and optical limiting activity of PABA combined with silver nanoparticles.

The Effect of Chromophores Concentration on the Nonlinear Optical Activity of Methacrylic Copolymers with Quinoxaline Chromophores in the Side Chain

The Effect of Chromophores Concentration on the Nonlinear Optical Activity of Methacrylic Copolymers with Quinoxaline Chromophores in the Side Chain

Multimodal Optically Nonlinear Nanoparticles Exhibiting Simultaneous Higher Harmonics Generation and Upconversion Luminescence for Anticounterfeiting and 8‐bit Optical Coding

AbstractNonlinear optical materials are essential in areas such as nanophotonics, optical information processing, and biomedical imaging. However, nanomaterials employed for these diverse applications to date are efficient only for one type of nonlinear optical activity. Herein, the first multimodal nonlinear optically active class of nanomaterials based on lanthanide‐doped lithium niobate nanoparticles, which simultaneously exhibit unprecedentedly efficient second and third harmonic generation, as well as up‐conversion photoluminescence, is reported. These dielectric nanoparticles retain their high nonlinear optical conversion efficiency both as powder and as aqueous colloidal solution. The high stability also allows for the fabrication of optically active biocompatible micron‐sized fibers and polymer‐based 3D‐printable objects, as well as for fingerprint detection. Finally, the first 8‐bit coding platform purely based on multimodal nonlinear optical activity originating from different parametric and nonparametric processes is demonstrated, showcasing the technological potential of these materials for both anti‐counterfeiting and advanced optical information processing.

Theoretical investigations on structural, spectral, NBO, NLO and topology exploration (AIM, ELF, LOL, RDG) of piperazine-2,5-dione oxalic acid monohydrate

The present work investigates the structural stability and nonlinear optical (NLO) activity of piperazine-2,5‑dione oxalic acid monohydrate (PDOAH) using quantum chemical computational techniques. The optimized molecular structure and vibrational wavenumbers of the PDOAH molecule are determined by density functional theory (DFT) with B3LYP/6–311G(d,p) basis set. The vibrational wavenumbers, IR intensities, Raman activities and their corresponding PED values are obtained and analysed. Natural bond orbital (NBO) analysis is carried out to determine inter and intramolecular charge transfer interaction, intermolecular hydrogen bonding and hyperconjugative interactions that stabilize the structure. The charge transfer interaction, electrophilic, nucleophilic and chemical reactivity sites are identified with the aid of molecular electrostatic potential (MEP) and frontier molecular orbital (FMO) analysis. The TD-DFT method is utilized in UV–Vis spectral analysis for the molecule in the water solvent. RDG and IRI analysis is performed to spot the van der Waals interaction and steric effect within the molecule. The Hirshfeld surface analysis is carried out to scrutinize the intermolecular interactions. The nonlinear optical (NLO) parameters of PDOAH are evaluated through DFT calculation and compared with that of urea.

Physicochemical and Nonlinear Optical Properties of a Stilbazolium Family Single Crystal with Third Order Nonlinear Optical Activity

AbstractA novel counter anion group was incorporated with the organic stilbazolium cation (C16H19N2+) to yield a new third‐harmonic‐generation‐active single crystal of 4‐[2‐(4‐dimethylamino‐phenyl)‐vinyl]‐1‐methyl‐pyridinium 2‐nitroaniline‐4‐sulfonate (DSNA). The slow evaporation solution growth technique is employed to obtain DSNA crystals, whose nonlinear responses are analysed through a continuous wave laser Z scan experiment. The thermally induced strong reverse saturation absorption and self‐defocusing behaviour of the DSNA crystal suggests that the material could be used as an optical limiting device. Optical characterization shows that the lower absorption edge falls in the visible region (530 nm), with a broad transparency range of 0.53 to 1 μm. Exploration of other optical constants, such as extinction coefficient (k=10−4), emission wavelength (602 nm – red light), optical (σopt=1010 Ωm−1) and electrical conductivity (σelc=1011 Ωm−1) also concludes that the DSNA crystal could be potentially employed in optoelectronic devices. The various bonds and their corresponding lengths and angles involved in the formation of DSNA ionic crystal are evaluated by means of single‐crystal X‐ray diffraction (SCXRD). Linear and nonlinear optical property findings undoubtedly affirm that the titular DSNA crystal is an effective nonlinear optical (NLO) crystal.

Spectroscopic, Topological and NLO Activity of N N’ Diphenyl Thiourea Acetone Monosolvate: Experimental and Theoretical Approach

The compound N,N’-Diphenylthiourea acetone monosolvate was synthesized using slow evapouration technique and characterized by FT-IR, FT-Raman, UV-visible spectra. The optimized molecular geometry (bondlength, bondangle and dihedral angle), the complete vibrational frequency were calculated by using density functional theory (DFT) B3LYP method with the help of 6-31 G(d,p) basis set. The protonated N–H…O intermolecular interaction liable for the NLO activity was deliberated using DFT method along with experimental spectroscopic techniques. The inter and intramolecular interactions accountable for the stabilization of the material was done via NBO and AIM analysis. In addition, the molecular electrostatic potential, frontier molecular orbital, global reactivity descriptors, Hirshfeld surface and 2D-fingerprint was analyzed to acquire a greater understanding of the molecular effect. UV-Vis spectrum of DPTA crystal exhibits good optical transmittance in the spectral analysis. By using spectroflurometer technique the green band region was observed in fluorescence emission spectrum. The dipole moment, polarizability, first-order hyperpolarizability (α 0), related properties (β, α 0 and Δα) and second-order hyperpolarizabilties were calculated for the identification of non-linear optical activity of the molecule. The molecular docking studies were performed to investigate the binding affinity of legend with target receptor.

Computational Study on Piperazine‐1,4‐Diium Acetate Using Dft Investigations: Structural Aspects, Topological and Nonlinear Optical Properties

AbstractThe work aims to investigate the nonlinear optical (NLO) activity of piperazine‐1,4‐diium acetate (PAA) molecule utilizing computational techniques. The computational calculations are performed using density functional theory (DFT) to explore the vibrational modes, electronic and NLO properties of PAA by comparing them with piperazine and acetic acid molecules. The natural bond orbital analysis is performed to identify hydrogen bonding and charge transfer interaction. A vibrational analysis is carried out and the assignment of fundamental modes is done using the vibrational energy distribution analysis (VEDA) program. Molecular electrostatic potential, frontier molecular orbital, electron localization function, localized orbital locator and Fukui analysis are carried out to identify chemical reactivity and charge transfer interaction. The UV–visible analysis is performed to obtain the electronic absorption spectrum. The hole–electron analysis is performed for the first five excitations to identify the type of excitation. The atoms in molecules, reduced density gradient and independent gradient model are performed to identify the hydrogen bonding, steric and van der Waals interactions. Hirshfeld analysis is performed to explore the intermolecular interactions within the PAA molecule. The NLO calculation is performed to evaluate the NLO parameters. The obtained results show that the PAA molecule is suitable for NLO applications.

Theoretical investigation of the performance of nonlinear optical properties in Push–pull chromophores derivatives of acrylo–azobenzene

Due to their strong molecular hyperpolarizability, organic push–pull materials are gaining interest for nonlinear optical applications. We were able to characterize the intramolecular charge transfer and the distribution of the electron cloud within the molecular unit by exciting these materials under the influence of an electric field. The series products of conjugated monomers derived from acrylo–azobenzene containing in the para position the attracting groups (–H, –NO2, –COOC2H5, –SO3H and –COOH) exhibit good nonlinear optical activity. We computed the nonlinear optical characteristics of these compounds as well as exploiting the theoretical calculations of DFT and AM1 to determine their hyperpolarizabilities. Besides, we investigated the increase in hyperpolarizability in the push–pull model of organic compounds under the effect of the strength of attracting groups, the existence of the conjugated [Formula: see text]-electron and the azo bridge.

Three-in-One Tetrahedral Functional Units Constructing Diamondlike Ag2In2SiS3.06Se2.94 with High-Performance Nonlinear-Optical Activity.

Exploration of new functional materials with enhanced performance from known ones is always an attractive strategy. A new infrared (IR) nonlinear-optical (NLO) mixed chalcogenide Ag2In2SiS3.06Se2.94 (1), was obtained through partial congener substitution originated from Ag2In2SiS6 (0). 1 crystallizes in the monoclinic space group Cc, and its three-dimensional (3D) polyanionic network is composed of {[In4Si2Se5(S/Se)11]12-}∞ helical chains sharing S/Se(5) corner atoms with cavities embedded with counterion Ag+ ions. It exhibits a much enhanced NLO response compared to that of 0, reaching 1.1 × AgGaS2. Further theoretical analysis results indicate that the large NLO response can be attributed to the synergistic effect of AgQ4 and InQ4 tetrahedral functional motifs. This work not only reports a new high-performance IR NLO material but also enriches the partial ion substitution strategy to obtain new functional materials.

A Dual-Purpose Ce(III)-Organic Framework with Amine Groups and Open Metal Sites: Third-Order Nonlinear Optical Activity and Catalytic CO2 Fixation.

The present work focuses on the synthesis and properties of a novel multifunctional cerium(III) MOF, [Ce2(data)3(DMF)4]·DMF (data2-: 2,5-diaminoterephthalate), abbreviated as NH2-Ce-MUM-2. Its crystal structure reveals an intricate 3D 4,5-connected framework with a xah topology. This MOF features unique properties, such as open metal sites, presence of free amino groups, and high stability. Two main applications of NH2-Ce-MUM-2 were investigated: (i) as a heterogeneous catalyst in the CO2 fixation into cyclic carbonates and (ii) as a material with third-order nonlinear optical activity. As a model reaction, the cycloaddition of CO2 to propylene oxide to give the corresponding cyclic carbonate was explored under mild conditions, at the atmospheric pressure of carbon dioxide and in the absence of cocatalyst and added solvent. Various reaction parameters were investigated toward optimization and exploration of substrate scope, revealing up to 99% product yields of cyclic carbonate products. Besides, the structure of NH2-Ce-MUM-2 is highly stable, permitting its recyclability and reusability in further catalytic experiments. The significant contributions of free amino groups and open metal sites within this catalyst were particularly considered when proposing a potential mechanism for the reaction. Z-Scan measurements were used to evaluate the nonlinear optical (NLO) properties of NH2-Ce-MUM-2 at various laser intensities. A high two-photon absorption (TPA) under greater incident intensities shows that NH2-Ce-MUM-2 might be applicable in optical switching devices. Besides, the self-focusing effects of NH2-Ce-MUM-2 under various incident intensities were highlighted by the nonlinear index of refraction (n2). By reporting the synthesis and characterization of a novel MOF, along with its highly promising catalytic and NLO behavior, the current study introduces an additional example of multifunctional material into a growing family of metal-organic frameworks.

Durable organic nonlinear optical membranes for thermotolerant lightings and in vivo bioimaging

Organic nonlinear optical materials have potential in applications such as lightings and bioimaging, but tend to have low photoluminescent quantum yields and are prone to lose the nonlinear optical activity. Herein, we demonstrate to weave large-area, flexible organic nonlinear optical membranes composed of 4-N,N-dimethylamino-4ʹ-Nʹ-methyl-stilbazolium tosylate@cyclodextrin host-guest supramolecular complex. These membranes exhibited a record high photoluminescence quantum yield of 73.5%, and could continuously emit orange luminescence even being heated at 300 °C, thus enabling the fabrication of thermotolerant light-emitting diodes. The nonlinear optical property of these membranes can be well-preserved even in polar environment. The supramolecular assemblies with multiphoton absorption characteristics were used for in vivo real-time imaging of Escherichia coli at 1000 nm excitation. These findings demonstrate to achieve scalable fabrication of organic nonlinear optical materials with high photoluminescence quantum yields, and good stability against thermal stress and polar environment for high-performance, durable optoelectronic devices and humanized multiphoton bio-probes.