NLO Devices Research Articles

Investigation on induced smectic phases in double hydrogen bond liquid crystal complexes derived from aromatic carboxylic acids: Experimental and quantum chemical approaches

In the present study, double Hydrogen bond liquid crystal (HBLC) complexes in different mole ratio (1:1 and 1:2) have been isolated from symmetrical aromatic dicarboxylic acid of non-mesogenic compound 1,3-Phenylenediacetic acid (1,3-PDA) and mesogenic compound 4-n-dodecyloxybenzoic acid (12 OBA). Fourier transform infrared Spectroscopy (FTIR) explores the presence of functional groups in the title complexes. Formation of H-bond between 1,3-PDA and 12 OBA is experimentally confirmed by observing the FTIR peak at 3639 cm−1 (1:1 ratio). Induced mesophases and its textures along with transition temperatures are analyzed using polarizing optical microscope (POM) and differential scanning calorimetry (DSC). The layered structures (smectic phases) and their molecular mechanism has been analyzed using density functional theory (DFT). Further, the establishment of H-bond in the title complex has been investigated with the aid of optimized geomentry, molecular electrostatic potential (MEP) and reduced density gradient (RDG) analysis. The band gap energy of title complex (1:1) is calculated by UV–Vis spectrometer and the same has been justified by HOMO-LUMO studies. Maximum absorption in the UV region and moderate bandgap energy (Eg = 4.22 eV) of the title complex clearly indicates its potential application in NLO, optoelectronics and laser tuning devices. In addition to that, LC parameters and its effect on mesophase are reported using experimental and computational methods.

Growth of L asparagine monohydrate doped potassium dihydrogen phosphate semiorganic crystals and its structural, thermal and optical properties

A novel semiorganic crystal is harvested by doping organic amino acid L asparagine monohydrate (LAM) with inorganic compound Potassium dihydrogen phosphate (KDP) by adopting slow evaporation method. Rietveld refinement of the XRD data was performed and the structural study exhibits single phase nature of the LAM doped KDP (LAM-KDP) crystals with a slight decrease in c-axis of the unit cell parameters. Other crystallographic parameters such as crystallite size and strain were also evaluated. The interaction of LAM with KDP was studied from FT-IR analysis by detecting functional groups. The constituting elements of the crystal were identified by energy dispersive X-ray (EDX) analysis. Etching study has been employed to study surface morphology of these crystals. From UV–vis transmittance data, optical band gap and different optical constants like Urbach energy, dielectric constants, electrical and optical conductivities were evaluated. Optical transparency of the LAM-KDP crystals is observed to increase. The third order nonlinear susceptibility χ(3) and nonlinear refractive index n2 of the grown crystals have been predicted using empirical Miller's rule. The value of χ(3) has increased from 1.87 × 10−13 esu to 4.29 × 10−13 esu due to LAM doping. Change in enthalpy (ΔH), change in Gibb's free energy (ΔG) and activation energy Ea during chemical reaction were calculated by thermogravimetric analysis (TGA). Thermal decomposition characteristics of the crystals were analyzed by differential scanning calorimetry (DSC). The high transparency of LAM-KDP crystals in the entire visible spectrum and larger values of nonlinear susceptibility χ(3) and nonlinear refractive index n2 make the synthesized crystal applicable for NLO and optoelectronic devices applications.

A novel Cadmium metal-organic framework with exceptional nonlinear optical properties: Unveiling anisotropic charge transport and optical limiting behavior

A novel non-centrosymmetric Cadmium Metal-Organic Framework (Cd-MOF) crystal with chemical formula CdC8N8H14O2S4 was synthesized and characterized. The band structure and optical limiting properties of the Cd-MOF were investigated using Band structure calculations and Optical limiting studies. The band structure analysis showed that the crystal displayed a larger, highly dispersive band, highlighting significant anisotropic n-channel charge carrier mobility. The optical limiting study demonstrated that the Cd-MOF exhibited Reverse Saturable Absorption (RSA) behaviour with an optical limiting threshold value of 1094 kW/cm2. The NLO behaviour of the Cd-MOF provides a promising potential for its application in NLO devices.

DFT/TD-DFT Study of D–?–A dyes explore the NLO properties

The molecular structures and optical properties of six different N.dimethylphenylendiamino dyes were analyzed using a combination of DFT functionals (B3LYP and Cam-B3LYP/6-311+G(p,d)). The six dyes are D1-D6. The various parameters of the solvated phase, such as the polarizabilities, hyperpolarizabilities, peak absorption wavelengths, and HOMO-LUMO energy gaps, were calculated and analyzed. The results of the study are in agreement with the results of the NLO activity order thiophene linker > pyrrole bridge. Compared to the dipyrrole versions, the designed dithiophene-linker dyes exhibit longer absorption wavelengths and smaller HOMO-LUMO gaps. The predicted first hyperpolarisability of dyes D1-D3 are higher than that of D4-D5. This is mainly due to its enhanced electron-withdraw ability and the long p-conjugating action of the thiophene moiety. Highly elevated total hyperpolarisability of the designed dyes, suggests its potential application in organic NLO devices, which is expected to be useful.

Influence of adsorption of gold and silver nanoclusters on structural, electronic, and nonlinear optical properties of pentacene-5,12-dione: a DFT study

The present study deals with the investigation of the change in the hyperpolarizability of Pentacene-2,5-dione (PD) on the introduction of the gold (Au) and silver (Ag) nanoclusters using the density functional theory (DFT). The involvement of the nanoclusters induces the intramolecular interactions, which is confirmed by the electrostatic potential plot and Mulliken charge distribution. The process of adsorption of metal clusters on the surface of PD is investigated by absorption spectra and the Raman spectra analysis. The global reactivity parameters validate a hike in the reactivity of the PD after the adsorption of Ag3 and Au3 nanoclusters. The study reported extraordinary enhancement in the hyperpolarizability of the metal nanoclusters adsorbed complexes. The high value of hyperpolarizability for PD-Ag3 (184.22 × 10−30esu) and PD-Au3 (2057.26 × 10−30esu) validates their applications in highly efficient NLO devices. The statistical calculation of radiative lifetime and light-harvesting efficiency reveals that probe PD can fruitfully contribute to the development of photo luminescent material and photosensitizer dye in dye-synthesized solar cells.

A study of thermal stability, vibrational spectroscopy, electric response and linear and nonlinear optical properties of pure PVP polymer for solar cell and NLO devices

A study of thermal stability, vibrational spectroscopy, electric response and linear and nonlinear optical properties of pure PVP polymer for solar cell and NLO devices

Exploring the Crystal, FT-IR, Optical, and NLO Properties of 3,4-Dichloro-6-Ehtyl-6H-Pyrano[3,2-c]Quinoline-2,5-Dione (DCPQ)

Theoretical calculations are fulfilled via DFT_B3PW91_SDD for DCPQ molecule. The experimental IR spectrum is scanned in the range 500–4000 cm−1 and compared with calculated IR. Detailed IR assignments are aided using GV5.0.9 program. The accuracy of calculation level is acknowledged by established agreement among recorded and computed wavenumbers. Frontier analysis for DCPQ molecular orbitals shows a considerable bandgap offset (3.78 eV) and overall dipole moment (TDM=7.64 D). Such results push DCPQ forward to be a highly active and more efficient replacer for current Si & Ge photovoltaics. Also, DCPQ reveal a remarkable NLO response 〖(β〗_DCPQ=4.29 * 10^(-30) esu ~12β_urea that made DCPQ a prime candidate for forthcoming NLO devices.

Polycyclic aromatic hydrocarbon-substituted push-pull chromophores: an investigation of optoelectronic and nonlinear optical properties using experimental and theoretical approaches.

A series of new push–pull chromophores were synthesized in moderate to very high yields (65%–97%) by treating TCNE and TCNQ with alkynes substituted by electron-rich diethylaniline and polycyclic aromatic hydrocarbons. Some of the chromophores exhibit strong intramolecular charge-transfer bands in the near-IR region with λmax values between 695 and 749 nm. With the help of experimental and theoretical analysis, it is concluded that the trend in λ max values is affected by PAH substituents sterically, not electronically. Steric constraints led to the increased dihedral angles, reducing conjugation efficiencies. The absorption properties of push-pull compounds have been investigated in solvents possessing different polarities. All chromophores exhibited positive solvatochromism. As an additional proof of efficient charge-transfer in push–pull chromophores, quinoid character (dr) values were predicted using calculated bond lengths. Remarkably, substantial dr values (0.045–0.049) were predicted for donor diethylaniline rings in all compounds. The effects of various polycyclic aromatic hydrocarbons on optical and nonlinear optical properties were also studied by computational methods. Several parameters, such as band gaps, Mulliken electronegativity, chemical hardness and softness, dipole moments, average polarizability, first hyperpolarizability, were predicted for chromophores at the B3LYP/6-31++G(d,p) level of theory. The predicted first hyperpolarizability β(tot) values vary between 198 to 538 × 10–30 esu for the reported push–pull chromophores in this study. The highest predicted β(tot) value in this study is 537.842 × 10–30 esu, 8150 times larger than the predicted β(tot) value of benchmark NLO material urea, suggests possible utilization of these chromophores in NLO devices. The charge-transfer character of the synthesized structures was further confirmed by HOMO-LUMO depictions and electrostatic potential maps.

Non-Linear Optical Properties and Global Reactivity Descriptors by ab initio Hartree-Fock (H.F.) Calculations of Simple Coumarins

In this present analysis, the measurement of optimized molecular structure and molecular hyperpolarizability (βtotal) of simple coumarin molecules were investigated using the HF method at 6-311G basis set level Gaussian09W. The measured nonlinear optical parameters (NLO); polarizability (α), the anisotropy of the polarizability (Δα), and first-order molecular hyperpolarizability (βtotal) of the studied coumarins indicate promising optical properties. The energy difference between HOMO and LUMO helped determine the molecular descriptors; global hardness (η), softness (σ) electronegativity (χ) Chemical potential (μ), and electrophilicity index (ω) in gas and different solvents. The molecular hyperpolarizability (βtotal) and descriptors that have been calculated in the solvent medium were taken into consideration through the Polarizable Continuum Model (PCM), This study shows the high static hyperpolarizability exhibited by HNR, FXT, and CNT and offers the potential the materials may have for NLO devices. The molecular descriptors, hardness, and chemical potential values are high for CNT and UCAcompared to other studied coumarins. This suggested that CNT and CA have the most significant chemical potential resistance to change the number of electrons among the other molecules.

Molecular docking, spectroscopic, and quantum chemical studies on aromatic heterocycle tetrakis(4-pyridyl)cyclobutane regioisomers: potential membrane-permeable inhibitors.

Aromatic heterocyclic compounds are commonly used in pharmaceutical and agrochemical products. The usage has been also extended in the production of corrosion inhibitors and electronic, opto-electronic, and NLO devices. The four regioisomers of the aromatic heterocyclic molecule, tetrakis(4-pyridyl)cyclobutane (tpcb), were optimized, and their chemical, electronic, and biological properties were examined. The rctt and rtct isomers were isolated and further characterized by the infrared and Raman spectroscopic techniques, and their vibrational modes with attention on important functional groups were discussed. The theoretical vibrational data obtained by DFT/B3LYP/6-311++G(d,p) were in very good agreement with the experimental ones. The occupancy, bond polarization, hybridization of the N-C bond, bonding characteristics between the pyridyl carbon and cyclobutane moiety, and distribution of electron density for the four tpcb isomers have been explored through NBO analysis. The inversion barrier of the cyclobutane moiety was obtained based on the optimized structures of the planar and puckered configurations of the isomers. The rccc isomer exhibited the least electrophilic character compared to the other tpcb isomers. The chemical significance of tpcb has been further explained by the wave function analyses. Molecular docking results revealed that the tpcb ligand would possess a potential anti-viral and anti-bacterial activity via a membrane-permeable mechanism.

The electronic and optical absorption properties of pristine, homo and hetero Bi-nanoclusters

The TD-DFT and DFT calculations are applied to pristine, homo and hetero Bi nanoclusters based on additive acetylene; pyrrole and thiophene monomers. Results showed that linear optical properties are improved by additive thiophenes while nonlinear are enhanced by pyrroles. Hetero BiQD nanoclusters possesses a highly efficient linear and nonlinear optical responses than both pristine and homo nanoclusters. Particularly, hetero BiQD = C2N nanocluster are expected to be widely acknowledged in NLO devices. The optical absorption spectra also depend on the attached monomer, where the UV–Vis prominent absorption peak of pristine Bi flakes can be red shifted to higher wavelengths by attaching CHN and C2N while kept unchanged by attaching SN or NS. The red shift in the first case, the active electrons from monomer not only passivate the edged atoms but also decrease energy gap. Contradictory, in second case, the monomers acts as passivation element or group with unremarkable effect on energy gap.

Growth, theoretical, optical and dielectric properties of a semi-organic zinc acetate picolinium succinate (ZAPS) single crystals for nonlinear optical applications

Nonlinear optical material Zinc Picolinate dihydrate (ZPD) was synthesized by slow evaporation solution growth technique. The grown crystals were characterised by Single crystal X-ray diffraction analysis. The presence of functional groups in the grown crystal was analyzed using FT-IR spectrum. The UV–vis spectrum shows a low absorption in the entire visible region. Optical band gap of the grown crystal was found to be 4.46 eV. The evaluation of optical constants by employing UV–visible absorbance data such as, reflectance, extinction coefficient, refractive index, are supportive towards good performance as NLO devices. The nonlinear optical behavior from the non-centrosymmetric crystal was observed by the generation of frequency doubled (2ω) optical radiation when subjected to pulsed Nd:YAG laser (1064 nm,10 ns,10 Hz) using Kurtz-Perry method.

Synthesis, growth, optical and third-order nonlinear optical properties of glycine sodium nitrate single crystal for photonic device applications

Glycine and its related compounds play a prominent role in the field of nonlinear optical studies and of fibre optical communication. In the present work, glycine sodium nitrate (GSN) crystal was grown using the method of slow evaporation method. The GSN crystal belongs to space group Cc in the monoclinic system. Using the FTIR spectrophotometer, the different functional groups have been qualitatively identified. A UV–Vis–NIR spectroscopy was used to record the optical absorption spectra, and the optical energy bandgap of GSN crystal is reported. The SHG conversion efficiency of GSN is determined by Kurtz and Perry technique. The Z-scan experiment was conducted to analyze GSN crystal for third-order NLO behavior and it is used to calculate the values of the nonlinear absorption coefficient, nonlinear refractive index, and third-order nonlinear susceptibility. Third-generation harmonic studies reveal that GSN is an excellent material useful in the fabrication of NLO devices due to its nonlinear response characteristics. The thermal stability of the grown crystal was determined through TG/DTA examination. Also photoconductivity studies confirm the negative photoconductive behavior of GSN and I–V characteristics measurement that have been carried out. The dielectric loss is significantly low and this supports defect-free growth of the crystal. These properties of GSN make it a good candidate in the fabrication of NLO devices.

Nonlinear optical activity of imino-dyes with furan, thiophene or thiazole moieties as π-conjugated bridge: a computational investigation

ABSTRACT The electronic, linear and nonlinear optical properties of some heterocycle-containing imino-dyes, namely, the synthesised dyes 1–3 and the designed dye 4, were evaluated using suitable long-range corrected DFT functionals. HOMO–LUMO gaps, dipole moments, polarisabilities, and first hyperpolarisabilities were calculated using CAM-B3LYP, ωB97XD and LC-ωPBE methods combined with the 6-311++G(d,p) basis set using CAM-B3LYP/6-31G(d,p) optimised geometries. The calculated molecular hyperpolarisabilities, µβ, increase in the order 1 < 2 < 3 as expected experimentally. The enhancement of µβ when passing from dye 1 to dye 2 is due to the replacement of furan by thiophene and the increase of µβ when passing from dye 2 to dye 3 is due to the change of the thiophene position from the acceptor side to the donor side. Interestingly, the replacement of thiophene (dye 2) by thiazole (dye 4) leads to a notable increase of the NLO response. The electronic transitions data of dyes 1–4 were calculated at the CIS/6-31G(d,p) level of theory and the predicted order 1 < 2<3 < 4 of µβ values is conveniently explained using the two-level model based on the calculation of the dipole moment absolute change, |ΔµEG |, from the ground to the excited state. Consequently, dye 4 could be a promising candidate for organic NLO devices.

Giant Enhancement of Second Harmonic Generation Accompanied by the Structural Transformation of 7‐Fold to 8‐Fold Interpenetrated Metal–Organic Frameworks (MOFs)

AbstractInterpenetration in metal–organic frameworks (MOFs) is an intriguing phenomenon with significant impacts on their properties, and functional applications. Herein, we show that a 7‐fold interpenetrated MOF (1) is transformed into an 8‐fold interpenetrated MOF by the loss of DMF in a single‐crystal‐to‐single‐crystal manner. This is accompanied by a giant enhancement of the second harmonic generation (SHG ca. 125 times) and two‐photon photoluminescence (ca. 14 times). The strengthened π–π interaction between the individual diamondoid networks and intensified oscillator strength of the molecules aid the augment of dipole moments and boost the nonlinear optical conversion efficiency. Large positive and negative thermal expansions of 1 occur at 30–150 °C before the loss of DMF. These results offer an avenue to manipulate the NLO properties of MOFs using interpenetration and provide access to tunable single‐crystal NLO devices.

Giant Enhancement of Second Harmonic Generation Accompanied by the Structural Transformation of 7-Fold to 8-Fold Interpenetrated Metal-Organic Frameworks (MOFs).

Interpenetration in metal-organic frameworks (MOFs) is an intriguing phenomenon with significant impacts on their properties, and functional applications. Herein, we show that a 7-fold interpenetrated MOF (1) is transformed into an 8-fold interpenetrated MOF by the loss of DMF in a single-crystal-to-single-crystal manner. This is accompanied by a giant enhancement of the second harmonic generation (SHG ca. 125 times) and two-photon photoluminescence (ca. 14 times). The strengthened π-π interaction between the individual diamondoid networks and intensified oscillator strength of the molecules aid the augment of dipole moments and boost the nonlinear optical conversion efficiency. Large positive and negative thermal expansions of 1 occur at 30-150 °C before the loss of DMF. These results offer an avenue to manipulate the NLO properties of MOFs using interpenetration and provide access to tunable single-crystal NLO devices.

Synthesis and DFT studies of the structure - NLO activity evaluation of 2-(4-methoxyphenyl)-1,4,5-triphenyl-2,5-dihydro-1H-imidazole

Synthesis, characterisation and single crystal X-Ray studies of 2-(4-methoxyphenyl)-1,4,5-triphenyl-2,5-dihydro-1H-imidazole are reported. Here after the compound is denoted as TSI. Small Angle X-Ray Diffraction (SXRD) showed that the crystal belonged to Monoclinic, P21/c group. The electronic and structural properties of TSI were investigated by DFT and TD-DFT methods. This molecule is a good candidate to be used in OLED devices because of high electron transport mobility and low λe value. The difference between λe and λh is smaller so that it has a better hole-electron transport balance in OLED devices. The calculated static first order hyperpolarizability β(000), showed that the material exhibited good non-linear optical behaviour and could be used for NLO devices. Fukui indices were calculated to identify the reactive sites of the title compound.

Computational study of linear and nonlinear optical properties of substituted thiophene imino dyes using long-range corrected hybrid DFT methods

The molecular structures, linear and nonlinear optical properties of a series constituted by four R-substituted thiophene imino dyes, namely A(R = SO2Me), B(R = SO2Ph), C(R = NO2), and D(R = C2(CN)3) were analysed using CAM-B3LYP, ωB97XD and LC-ωPBE hybrid DFT functionals in combination of the 6-311++G(d,p) standard basis set. The dipole moments, polarisabilities, HOMO-LUMO energy gaps, maximum absorption wavelengths and first hyperpolarisabilities were calculated in the gas phase and the obtained results are in good agreement with experimental NLO activity order A < B < C. Compared to synthesised dyes A-C, the designed dye D presents a longer maximum absorption wavelength and a lower HOMO-LUMO gap because of the appreciable stabilisation of its LUMO energy. These results were confirmed by the calculation of the total second-order stabilisation energy E(2) defined in the context of the NBO population analysis. Consequently, dye D is predicted to exhibit a higher first hyperpolarisability in comparison with dyes A-C. This result can be justified by the enhanced intramolecular charge transfer in dye D due to the stronger electron-withdrawing ability and the cumulative action of the long π-conjugation of the tricyanovinyl moiety. The very high total hyperpolarisability (27 times greater than that of para-nitroaniline) of the designed dye D suggests its promising use in organic NLO devices.

Experimental and theoretical studies on the bifurcated hydrogen bonded NLO active material of pure and crystal violet dye-doped L-argininium bis dihydrogen phosphate

Single crystals of pure and crystal violet dye-doped L-Argininium bis dihydrogen phosphate were grown using slow evaporation technique. The crystalline nature and the structure parameters were confirmed by powder X-ray diffraction technique. Blue and red shifting hydrogen bonds were predicted by DFT on the basis of vibrational spectral (FT-IR & FT-Raman), AIM and NBO analyses. Bifurcated NH⋯O and OH⋯O intermolecular hydrogen bonds in LADP molecule were visualized by Hirshfeld surface. 13C and 1H NMR spectroscopy confirmed the structure of LADP. Doped LADP crystal shows enhancements in the wavelength and longer lifetimes as identified from photoluminescence spectra and decay analysis respectively. The high values of electron mobility and low value of λelectron reflect the applicability of LADP in OLED devices. Enhancement in nonlinear optical parameters in dye-doped LADP crystal was revealed from the Z-scan technique which shows its usefulness in the fabrication of NLO devices.

Growth, Spectral, Optical, Studies of A Zinc Picolinate Dihydrate NLO Single Crystal

Nonlinear optical material Zinc Picolinate dihydrate (ZPD) was synthesized by slow evaporation solution growth technique. The grown crystals were characterised by Single crystal X-ray diffraction analysis. The presence of functional groups in the grown crystal was analyzed using FT-IR spectrum. The UV-vis spectrum shows a low absorption in the entire visible region. Optical band gap of the grown crystal was found to be 3.98 eV.The evaluation of optical constants by employing UV-visible absorbance data such as, reflectance, extinction coefficient, refractive index, are supportive towards good performance as NLO devices. The nonlinear optical behaviour from the non-centrosymmetric crystal was observed by the generation of frequency doubled (2ω) optical radiation when subjected to pulsed Nd:YAG laser (1064 nm,10 ns,10 Hz) using Kurtz-Perry method.