Jiurong Liu

Crystal growth and physical properties of UV nonlinear optical crystal zinc cadmium thiocyanate, ZnCd(SCN)4

Abstract Zinc cadmium thiocyanate, ZnCd(SCN) 4 (ZCTC) single crystals of optical quality have been grown from aqueous solution by controlled evaporation at 40 °C. The morphology of the crystal was indexed. Raman spectroscopy, refractive indices, optical transmission and optical damage threshold of the ZCTC crystal were all performed at room temperature. Violet and ultraviolet (UV) light output by frequency doubling of a 808 nm GaAlAs laser diode and a continuous wave Ti:sapphire laser at 760 nm were achieved. The dielectric constants, piezoelectric strain constants, electroptic coefficients, and direct current resistivities have also been measured.

Growth and properties of UV nonlinear optical crystal ZnCd(SCN)4

Abstract A second-order nonlinear optical coordination crystal, zinc cadmium thiocyanate, ZnCd(SCN) 4 (ZCTC) was grown as a frequency doubler, emitting UV light. A large typical single crystal with dimensions up to 15 × 7 × 7 mm 3 has been obtained by slow solvent-evaporation method for the first time. The infrared (IR) spectroscopy and X-ray powder diffraction (XRPD) of single crystals were performed at room temperature. The specific heat of the crystal has been measured to be 367.9 J/mol.K at 300 K. The thermal expansion coefficients, c- and a-oriented, have been measured to be −1.69 × 10 −5 and 1.95 × 10 −4 K −1 , respectively. The second harmonic generation (SHG) efficiency of ZCTC crystal is 51.6 times as high as that of urea reference, and the measured transmittance spectra from 190 to 3200 nm showed that the UV transparency cutoff occurs at 290 nm and the transmission is 73.22% at 380 nm. UV laser light of wavelength 380 nm has been achieved by the frequency doubling of a 760 nm laser diode at room temperature.

Studies on the growth and properties of magnesium-doped potassium lithium niobate single crystal

Magnesium-doped potassium lithium niobate (designated as Mg:KLN) single crystal free of cracks was grown for the first time. The tetragonal tungsten bronze structure of the Mg:KLN crystal was determined by X-ray powder diffraction; the lattice parameters were a = 1.261 and c = 0.398 nm. High-temperature X-ray powder diffraction patterns show that the expansion of the lattice with increasing temperature was less than that of the undoped crystal. The transmittance of the as-grown Mg:KLN crystal was measured. It only took 70 nm for the transmittance to increase to 70% from the cutoff of 380 nm. The transmittance for 404 nm was 50%, which was greater than that for the undoped crystal. Frequency-doubling experiment showed that the crystal generated blue light at a wavelength of 404 nm through noncritical phase matching frequency-doubling of an 808 nm diode laser at room temperature.

Preparation of zirconia xerogels and ceramics by sol–gel method and the analysis of their thermal behavior

Abstract Highly stable, homogeneous zirconia xerogels and ceramics were prepared from PZOs obtained by chelation of ethyl acetoacetate (Hetac) or acetylacetone (Hacac) to zirconium. The structure of PZO was analyzed by 1 H NMR. The thermal behavior of zirconia xerogels and ceramics were also determined by thermogravimetric/differential thermal analysis (TG/DTA), Fourier transform–infrared (FT–IR) spectroscopy and X-ray diffraction (XRD).

Strong luminescence of pure and yttria doped zirconia xerogels

Photoexcitation of intragap localized electronic states associated with lattice irregularities or defects in an insulating solid with a large band gap gives rise to a variety of photophysical and photochemical processes, the nature of which depends on the type of interaction between the incident light and the solid’s subsystem and on the experimental approach used. Zirconia (ZrO2) is a wide band-gap (5.0–5.5 eV) transition metal oxide with useful mechanical, thermal, optical, and electric properties. It is therefore used in a variety of applications, which include semiconductor substrates [1], damage “resistant” optical coatings [2], high temperature solid oxide fuel cells and oxygen sensors [3]. At room temperature, ZrO2 exists in the monoclinic form since the cubic or tetragonal phase is metastable [4]. However, the cubic or tetragonal phase can be stabilized when additives such as yttrium, magnesium, or calcium oxides are used. These additives “adjust” the crystallographic structure by introducing oxygen vacancies and alter the electronic structure. Generally, it is these modifications (i.e., the vacancies and changes in the geometric and electronic structure) which lead to the useful transport, chemical, and optical properties of doped zirconia [5]. The vacancies (defects) and electronic structure of pure and doped zirconia also make this material very attractive for applications in radiation or plasma-induced surface catalysis [6]. Luminescence studies can provide useful information about the electronic excitations and defects in pure and yttria-stabilized ZrO2 (YSZ) and several studies have been reported [7–10]. The present contribution reports the results of a study of the optical properties of yttria doped zirconia xerogels. The pure and yttria doped ZrO2 xerogel samples investigated in the present paper were obtained from polyzirconoxane (PZO) precursors (synthesized from zirconium oxychloride octahydrate and acetylacetone) [11] and have the chemical composition given in Table I. Samples having a thickness of 1.5 mm were used. Luminescence and excitation spectra were measured with a 2.5 nm monochrometer slit on a Japan Hitachi M-850 fluorescence spectrometer at room temperature. UV-Vis absorption spectra were determined also at room temperature employing a U-3500 UV-Vis-NIR spectrophotometer. On Fig. 1 are seen the absorption spectra of pure (curve 1) and yttria doped zirconia xerogels with

Polymeric di­aqua­tetra-μ-thio­cyanato-manganese(II)­mercury(II) bis(N,N-di­methyl­acet­amide) solvate

In the title complex, ¿[MnHg(SCN)(4)(H(2)O)(2)].2C(4)H(9)NO¿(n), each Mn atom is octahedrally coordinated to four equatorial thiocyanate N atoms and two axial water O atoms. The Mn atom and two O atoms lie on a twofold axis. Two kinds of crystallographically independent Hg atoms (denoted Hg1 and Hg2) are tetrahedrally coordinated with four thiocyanate S atoms and each Hg atom lies on a -4 axis. N,N-Dimethylacetamide molecules are connected to coordinated water molecules through hydrogen bonds. Each pair of Mn and Hg atoms is bridged via one thiocyanate ion. An Mn(2)Hg1Hg2(SCN)(4) 16-membered ring is formed as a unit and the four metal atoms are in a chair-form tetrahedral arrangement. The units are linked with one another and form infinite two-dimensional networks.