Ultraviolet Cutoff Wavelength Research Articles

Synthesis, structural, spectroscopic, mechanical, linear and nonlinear optical studies on 4-dimethylaminopyridinium p-toluenesulfonate: A comparative theoretical and experimental investigation

Single crystal of 4-(Dimethylamino)pyridinium p-toluenesulfonate (4DMPT) has been successfully grown by solution growth method and its structural characterization has carried out by X-ray diffraction methods. Single crystal XRD study shows that the grown crystal crystallized in the monoclinic system with unit cell dimensions a = 8.986 (6) A˚, b = 17.591 (5) A˚, c = 9.784 (8) A˚, β = 112.296˚(3), V = 1448.18 (17) A3 and Z = 4. The quantum chemical calculations have been carried out at HF and DFT (B3LYP/ CAMB3LYP/ M06–2X) with 6–311++G(d,p) levels to reach the optimized geometry, charge distributions and HOMO-LUMO nature. A good correlation is shown between computed and experimental structural parameters such as bond lengths and bond angles. The load dependent hardness values of the crystal have been analyzed. The optical spectrum revealed the ultra violet cut-off wavelength at 284 nm. The third order nonlinear optical responses have been studied by Z-Scan technique. The calculated value of third order non-linear refractive index (n2), third order non-linear absorption coefficient (β) and third order non-linear optical susceptibility (χ(3)) is 8.18 ×10−8cm2/W, 0.20 ×10−4cm/W and 12.88×10−6 esu, respectively.

Optical properties of 2-aminopyridine potassium dihydrogen phosphate cadmium chloride

A good-optical-quality crystal of 2-aminopyridine potassium dihydrogen phosphate cadmium chloride (2APKDPC) was grown through the slow evaporation technique at room temperature. The transparent and defectless bulk crystal of 2APKDPC with dimensions of 23 × 10 × 5 mm3 was grown through the solution growth method in a period of 90–95 d. From the single-crystal X-ray diffraction study, the measured lattice parameter values were a = 7·49 Å, b = 7·49 Å, c = 7·03 Å, α = β = γ = 90° and volume V = 394 Å3, which show that the grown 2APKDPC crystal belonged to the tetragonal crystal system. The crystalline nature of the grown crystal was confirmed by powder X-ray diffraction analysis. Fourier transform infrared analysis was carried out to identify metal coordination and the presence of various functional groups in the 2APKDPC crystal. In the recorded optical transmission spectrum, the ultraviolet cutoff wavelength was found to be 237 nm, and the optical energy bandgap value was also found from the absorption studies.

New transparent and thermally stable cardo poly(ether imide)s derived from 10,10-bis[4-(4-amino-2-pyridinoxy)phenyl]-9(10H)-anthrone

A new diamine bearing flexible ether, rigid pyridine, and bulky anthrone pendent group, 10,10-bis[4-(4-amino-2-pyridinoxy)phenyl]-9(10 H)-anthrone (BAPPA), was prepared in three steps from anthrone. BAPPA was reacted with six conventional aromatic dianhydrides in N, N-dimethylacetamide (DMAc) to form the corresponding new poly(ether imide)s (PEIs) via the poly(ether amic acid) (PEAA) precursors with inherent viscosities ranging from 0.85 dL g−1 to 1.26 dL g−1 and thermal imidization. All the PEAAs could be cast from DMAc solution and thermally converted into transparent, flexible, and tough PEI films with tensile strength of 72.2–112.4 MPa, tensile modulus of 1.8–2.1 GPa, and elongation at break of 10–18%. These PEIs were predominantly amorphous and displayed excellent thermal stability with the glass transition temperature of 290–388°C, the 5% weight loss temperature of 480–514°C, and the residue of 68–43% at 800°C in nitrogen. The PEIs derived from 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride and 4,4′-hexafluoroisopropylidenediphathalic anhydride exhibited excellent solubility in organic solvents such as N-methyl-2-pyrrolidinone, DMAc, N, N-dimethylformamide, pyridine, and even in tetrahydrofuran. Meanwhile, these PEIs also exhibited high optical transparency with the ultraviolet cutoff wavelength in the 374–427 nm range and the wavelength of 80% transparency in the range of 468–493 nm.

A new ultraviolet transparent hydra-cyanurate K2(C3N3O3H) with strong optical anisotropy from delocalized π-bonds.

A new metal hydra-cyanurate, K2(C3N3O3H), was synthesized by a slow evaporation method in aqueous solution. It possesses a short ultraviolet cutoff wavelength at 240 nm. First-principles calculations reveal that its birefringence (∼0.35@800nm) is two times larger than that of commercial calcite crystals. Therefore, K2(C3N3O3H) and metal cyanurates, are very promising ultraviolet birefringent materials in future optical devices.

Synthesis and characterization of novel fluorinated poly(ether imide)s containing pyridine and/or phenylphosphine oxide moieties

4-(4-Trifluoromethylphenyl)-2,6-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]pyridine (9FPBAPP), as a new aromatic diamine, was prepared by a modified Chichibabin reaction of 4-(4-nitro-2-trifluoromethylphenoxy)acetophenone with 4-triflouromethylbenzaldehyde, followed by a catalytic reduction. A series of fluorinated poly(ether imide)s containing pyridine and/or phenylphosphine oxide moieties were prepared from bis(3-aminophenyl)phenylphosphine oxide (BAPPO), 2,2′-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA), and 9FPBAPP via a conventional two-step thermal imidization procedure with various mole ratios of BAPPO and 9FPBAPP. All the polymers were amorphous and soluble in common organic solvents such as N, N-dimethylacetamide and N-methyl-2-pyrrolidone and had Tg’s of 277–285°C, 5% weight loss temperature of 521–550°C in nitrogen. Furthermore, high char yields and good limited oxygen index values indicated that these polymers exhibited good thermal stability and flame-retardant property. Tough and flexible polymer films also had good mechanical properties with tensile strengths of 75–99 MPa, tensile moduli of 1.1–1.6 GPa, and elongations at break of 12%–24% and low dielectric constants of 2.81–3.53 (1 MHz), as well as high optical transparency with the ultraviolet cutoff wavelength in the range of 350–384 nm.

Growth and characterization of succinic acid-mixed KHP crystal for NLO applications

Semiorganic single crystals of succinic acid-mixed potassium hydrogen phthalate (KHPSA) were grown from an aqueous solution by the slow evaporation method at room temperature. The structural properties of the grown crystals have been studied by single-crystal X-ray diffraction, powder X-ray diffraction and Fourier transform infrared spectral analysis. Ultraviolet (UV)–visible spectral analysis showed that the mixed crystal has a lower UV cutoff wavelength of 226 nm combined with good transparency of about 55% in a very wide range. The second harmonic generation efficiency test has been carried out and the results are discussed. Thermogravimetric–differential thermal analyses were carried out to characterize the melting behavior and thermal stability of the mixed crystal. The hardness profile of the sample is investigated by using the Vickers microhardness test. The electrical properties have been studied by carrying out dielectric constant studies. Determination of the microstructure and composition of the KHPSA crystal has been carried out by scanning electron microscopy with energy-dispersive spectroscopy.

Synthesis and characterization of novel fluorinated pyridine-based polyimides derived from 4-(4-trifluoromethylphenyl)-2,6-bis(4-aminophenyl)pyridine and dianhydrides

A series of new fluorinated pyridine-based polyimides (PIs) was synthesized by polycondensation of 4-(4-trifluoromethylphenyl)-2,6-bis(4-aminophenyl)pyridine with various aromatic dianhydrides in N, N-dimethylacetamide (DMAc) via the conventional two-step method. The inherent viscosities of the resulting poly(amic acid)s and PIs were 0.54–0.94 and 0.58–0.88 dLg−1, respectively. The obtained PIs were predominantly amorphous and soluble in polar solvents such as N-methyl-2-pyrrolidone, N, N-dimethylformamide, and DMAc at room temperature or upon heating at 70°C. They also displayed good thermal stability with the glass transition temperature of 324–416°C, the temperature at 5% weight loss of 546–584°C, and the residue of 58–69% at 750°C under nitrogen, as well as outstanding mechanical properties with tensile strengths of 69132 MPa, tensile moduli of 1.1–2.0 GPa, and elongations at break of 7–27%. Meanwhile, these PI films had dielectric constants of 2.95–3.22 (1 MHz), low water uptake 0.44–0.71%, and high optical transparency with the ultraviolet cutoff wavelength in the 388–406 nm range and the wavelength of 80% transparency in the range of 550–680 nm.

Ba(dl-C4H4O5) — An alkaline earth metal-dicarboxylate hybrid crystal with the synergy of multi-bonds

The organic–inorganic hybrid crystal, Ba(dl-C4H4O5), has been firstly prepared by hydrothermal method. It crystallizes in monoclinic crystal system with a centrosymmetric space group of P21/c with a=8.150(2) Å, b=10.447(3) Å, c=6.938(2) Å, β=95.599(3)° and Z=4. In this compound, the coexistence of organic ligand and the alkaline earth metal cation leads to the diversity of chemical bonds. The synergy of Ba–O ionic bonds and hydrogen bonds strengthens the crystal structure. Characterization of this earth metal-dicarboxylate hybrid crystal is described by using powder X-ray diffraction, infrared spectroscopy, UV–vis–NIR diffuse reflectance spectrum and the TG curve. In addition, Ba(dl-C4H4O5) possesses a short ultraviolet cutoff wavelength lower than 230nm determined by the electronic transition of C–O group, which signifies the potential use in UV region applications. And the electronic structure and optical properties are studied by first principle calculation method, which obtains a birefringence value of 0.04.

Structural, optical and mechanical property analysis of magnesium sulphate admixtured l-Threonine: A novel optoelectronic material

l-Threonine is an important amino acid and famous due to their property of frequency conversion and electro optic modulation. Single crystals of magnesium sulphate admixtured l-Threonine was grown by slow evaporation technique. Good quality single crystal with dimension 58×5×10mm3 was harvested after 60 days. The powder X-ray diffraction pattern of the grown crystal has been indexed. The optical transmission spectrum shows that the magnesium sulphate admixtured l-Threonine possess good optical transparency in the entire visible region with Ultra Violet cut-off wavelength at 250nm. The presence of fundamental functional groups was identified by Fourier Transform Infra Red spectral analysis. The structure of the grown crystal was established using Fourier Transform-Nuclear Magnetic Resonance spectral analysis. The thermal behaviour of the crystal has been discussed by Thermal Gravimetric Analysis and Differential Thermal Analysis. Magnesium sulphate admixtured l-Threonine was characterized by Energy dispersive analysis of X-ray. The second harmonic generation efficiency of magnesium sulphate admixtured l-Threonine crystal is found to be same as that of potassium dihydrogen phosphate crystal.

Growth, spectroscopic and physicochemical properties of bis mercury ferric chloride tetra thiocyanate: A nonlinear optical crystal

Single crystal of bis mercury ferric chloride tetra thiocyanate [Hg2FeCl3(SCN)4; (MFCTC)] was grown from ethanol–water (3:1) mixed solvent using slow evaporation solvent technique (SEST) for the first time. The cell parameters of the grown crystal were confirmed by single crystal XRD. The coordination of transition metal ions with the SCN ligand is well-identified using FT-IR spectral analysis. The chemical composition of MFCTC was confirmed using CHNS elemental test. The ESR spectral profile of MFCTC was recorded from 298K to 110K, which strongly suggests the incorporation of Fe3+ ion and its environment with respect to SCN ligand. The HPLC chromatogram of MFCTC highlights the purity of the compound. The UV–Vis–NIR studies revealed the ultra violet cut-off wavelength of MFCTC in ethanol as 338nm. The dielectric constant and dielectric loss of the sample were studied as a function of frequency and temperature. The TGA–DTA and DSC thermal analysis show that the sample is thermally stable up to 234.31°C, which is comparatively far better than the thermal stability of Hg3CdCl2(SCN)6; (171.3°C) and other metal–organic coordination complex crystals such as CdHg(SCN)4 (198.5°C), Hg(N2H4CS)4Mn(SCN)4 (199.06°C) and Hg(N2H4CS)4Zn(SCN)4 (185°C). The SHG conversion efficiency of MFCTC is found to be higher than KDP.

New oxyfluoride glass with high fluorine content and laser patterning of nonlinear optical BaAlBO3F2 single crystal line

A new oxyfluoride glass of 50BaF2-25Al2O3-25B2O3 (mol. %) with a large fraction of fluorine, i.e., F/(F + O) = 0.4, was prepared using a conventional melt-quenching method in order to synthesize new glass-ceramics containing nonlinear optical oxyfluoride crystals. The refractive index at 632.8 nm and ultra-violet cutoff wavelength of the glass were 1.564 and ∼200 nm, respectively. Eu3+ ions in the glass showed a high quantum yield of 88% in the photoluminescence spectrum in the visible region. BaAlBO3F2 crystals (size: 50–100 nm) showing second harmonic generations were formed through the crystallization of the glass. Lines consisting of BaAlBO3F2 crystals were patterned successfully on the glass surface by laser irradiations (Yb:YVO4 laser with a wavelength of 1080 nm, laser power of 1.1 W, scanning speed of 8 μm/s). High resolution transmission electron microscope observations combined with a focused ion beam technique indicate that BaAlBO3F2 crystals are highly oriented just like a single crystal. The present study proposes that the new oxyfluoride glass and glass-ceramics prepared have a high potential for optical device applications.

Preparation and Characterization of 2,2-bis[4-(3-Aminophenoxy)phenyl]propane/4,4′-Oxydianiline/4,4′-Oxydiphthalic Anhydride (3-BAPOPP/44ODA/ODPA) Polyimide Films with Various Co-monomer Ratios

A new diamine monomer 2,2-bis[4-(3-aminophenoxy)phenyl]propane (3-BAPOPP) was synthesized through two steps and its melting point was determined by differential scanning calorimetry (DSC). It was then copolymerized with 4,4′-oxydianiline (44ODA) and 4,4′-oxydiphthalic anhydride (ODPA) to obtain a series of aromatic polyimide(3-BAPOPP/44ODA/ODPA-PI) films. Fourier transform infrared (FT-IR) was used to characterize the structures of the monomer and the polyimide films. Water absorption, ultraviolet-visible (UV-Vis) spectroscopy, contact angle, DSC, and thermo-gravimetric analysis (TGA) were used to characterize the properties of 3-BAPOPP/44ODA/ODPA-P films. The results showed that the PI films had low water absorption in the range of 1.5%∼1.9%, low surface energy in the range of 43.3 ∼43.5 mJ/m2, glass transition temperature (Tg) in the range of 192.5°C∼226.1°C, and dielectric constant in the range of 2.79∼3.02 at 1 MHz. The films also exhibited good thermal properties and good optical properties, with the ultra violet cut-off wavelength being in the range of 346∼364 nm.

Growth and optical properties of UV transparent YAB crystals

Large and ultraviolet (UV) transparent YAl3(BO3)4 (YAB) crystals were grown by a high temperature top seeding method with Li2B4O7–AlBO3 as the flux. The UV cutoff wavelength of the YAB crystal was shorter than 190 nm. The refractive indices of the YAB at several wavelengths covering UV–visible and near infrared wavelength over the temperature range from 30 to 170°C were measured by the autocollimation method. The parameters of the Sellmeier dispersion equation were determined based on the experimental data. The phase matching curve of second harmonic generation was measured. The deviations of the phase matching angle for second harmonic generation at 473 nm as a function of temperature for the YAB crystals were investigated. The coefficient of frequency doubling d11 of the YAB crystal was measured to be 1·30 pm V−1 by a phase matching method.

Growth of YAl3(BO3)4 crystals with tungstate based flux

A new flux made of Li2WO4–B2O3 was used to grow YAl3(BO3)4 (YAB) crystals. The crystallisation region of YAB crystals was determined in the quasi-ternary system YAB–Li2WO4–B2O3. Large and transparent YAB crystals were grown by a high temperature top seeding method with Li2WO4–B2O3 as the flux. The volatility of Li2WO4–B2O3 flux was lower than that of the commonly used polymolybdate flux at high temperature. A much lower incorporation of tungstate into the crystals was observed. The ultraviolet cutoff wavelength of YAB crystal was shorter than 190 nm. The thermal expansion coefficients along two crystallographic directions over the measuring temperature range of 30–800°C were determined to be αa = 3·88×10−6 K−1 and αc = 12·5×10−6 K−1 respectively. The specific heat is ∼0·675 J g−1 K−1 at room temperature. The thermal conductivities at room temperature are 11·891 and 11·591 W m−1 K−1 along the a and c directions respectively.

Growth, optical, dielectric and ESR studies on tetrathiourea mercury(II) tetrathiocyanato manganate(II): An organometallic complex NLO crystal

Single crystals of tetrathiourea mercury(II) tetrathiocyanato manganate(II); Hg(N 2H 4CS) 4Mn(SCN) 4, (TMTM) were grown by slow solvent evaporation technique. The grown crystals were confirmed by single crystal and powder X-ray diffraction analysis. The optical absorption spectrum of TMTM in a mixed solvent of acetone and water shows the near ultra-violet cut-off wavelength corresponding to the absorption maximum as 335 nm. FT-IR spectrum identifies the characteristic absorption bands of thiourea and thiocyanate in both middle and far infrared regions, which further confirm the incorporation of both the ligands in the resulting compound. The electron spin resonance spectrum of TMTM was recorded both at room temperature and −196 °C, which reveals that the Mn environment is symmetrical with respect to the NCS ligand distribution. It is also interesting to note that there is no hyperfine coupling between Mn nucleus and its free electrons at both room temperature and −196 °C. The dielectric constant as well as dielectric loss of the sample were calculated for varying frequencies under different temperatures.

Crystal growth, structure and properties of bismuth triborate BiB3O6 crystal

BiB3O6 (BIBO) single crystals with size of 46×23×10 mm3 and weight of 26.0 g have been successfully grown by top-seeded method. Problems encountered in the growth process of this crystal have been discussed in detail, and the methods of growing high-quality large crystals have been put forward. The relationship between their structure and properties is studied. The space group of monoclinic BiB3O6 is C2 and the cell parameters are a=7.1203(7) A, b=4.9948(7) A, c=6.5077(7) A, β=105.586(8)″, and V=222.93(5) A3. The density of BIBO is 4.8965 g/cm3. The Mohs’s scale of hardness is 5.5–6. There is no cleavage face in the crystal. The transmittance of BIBO is about 80 percent in the range from visible coherent light to near-infrared light. The ultraviolet cutoff wavelength is at 276 nm. BiB3O6 is a biaxial crystal and has two sets of axes, and the relative orientation of (X, Y, Z) with regard to (a, b, c) is: X//b, (Y, c)=47.2°, (Z, a)=31.6°, determined by X-ray analysis combined with polarized microscopy. Second-harmonic-generation (SHG) experiments were carried out for the first time. In type I phase-matching (PM) directions (11.1°, 90°) and (168.9°, 90°), SHG conversion efficiencies of two directions for 1.064 μm light are up to 67.7% and 58%, respectively. We have also obtained the third-harmonic-generation (THG) of 1.064 μm. The comparative experiments between BIBO and KTP were carried out on conversion efficiency, transmittance and hardness. All the above results indicate that BiB3O6 is a kind of excellent nonlinear optical (NLO) crystal.