Single crystals of three new organic–inorganic hybrid compounds, tri[1-(diaminomethylene)uronium] hexachlorobismuthate ((C2H7N4S)3BiCl6·H2O, HATU-BCH), bis[1-(diaminomethylene)uronium] pentabromobismuthate, ((C2H7N4S)2BiBr5, HATU-BB), and bis [3,5-diamino-1,2,4-thiadiazol-2-ium] pentaiodobismuthate ((C2H5N4S)2BiI5, OHATU-BI), have been successfully grown by slow evaporation method. Their structures were determined by single-crystal X-ray diffraction, in which all anion sublattice structures consist of hexahalobismuthates octahedra with different connection modes involving isolated, shared-corner, and shared-edge. The spectra characters were studied by Infrared and Raman spectra, which interpreted by calculation of the density functional theory (DFT) method and diffuse reflectance spectra. Thermal properties were characterized by thermal gravimetric analysis and differential scanning calorimetry.(C2H7N4S)3BiCl6·H2O, (C2H7N4S)2BiBr5, and (C2H5N4S)2BiI5, have been synthesized, and single crystals have been obtained. BiX6 octahedra form isolated [BiCl6]3−, 1-D zig-zag infinite chains [BiBr5]2n−, and edge-sharing [Bi2I10]4−. DFT calculations and measurements of spectra and TG-DSC indicate that their band gaps are 3.40 eV, 2.59 eV, and 2.05 eV, respectively, and thermal stable.Download high-res image (115KB)Download full-size image

A series of 3-phenyl-5-isoxazolone and 3-methyl-5-isoxazolone-based compounds with different electron donors were synthesized. Fourteen single crystals in this family were obtained by slow evaporation. Single crystal X-ray studies showed that four new 3-phenyl-5-isoxazolone-based crystals, C20H18N2O2 (PDI), C15H11NO2S (PTI), C23H15NO2 (PFI), and C17H13NO2S (PMI-(I)), belong to the noncentrosymmertric space group. The inclinations to achieve noncentrosymmetric space groups in the 3-phenyl-5-isoxazolone-based crystals have been confirmed by first-principles calculations. Powder second harmonic generation (SHG) tests revealed that the abovementioned four acentric crystals exhibited very large SHG intensities that were about 1 to 3 times that of OH1 (a commonly used nonlinear optical crystal) under 2.09 μm light. Their UV-vis absorption, diffuse reflectance spectroscopy, and thermal properties were also characterized. Moreover, widely tunable and monochromatic terahertz difference frequency generation in the 3-phenyl-5-isoxazolone-based crystal C17H13NO3 (MLS) was realized for the first time.

A new noncentrosymmetric borate, Na3Y3(BO3)4, was grown in the Na2O–B2O3–NaF flux system. Its open-framework structure features a large hexagonal tunnel (5.92 Å in diameter), which is extremely rare in borates. First-principles calculations on its kinetic stability and optical properties were performed.

•The signs of NLO coefficients of LCB crystal were determined based on Maker fringe method and phase-matching method.•Compared with d22, the signs of d21, d23 and d14 are found to be negative, positive, and positive respectively.•The distribution of effective NLO coefficient (deff) for THG with LCB crystal are determined.•The optimal phase-matching angles for THG in LCB are (48.7°, 72.5°) and (65.3°, 37.5°) for two kinds of phase-matching.The signs of nonlinear optical (NLO) coefficients of La2CaB10O19 (LCB) crystal were determined by Maker fringe method and phase-matching method. Compared with d22, the signs of d21 and d23 are found by Maker fringe method to be negative and positive, respectively, and the sign of d14 is found to be positive by phase-matching method. Phase-matching angles for third harmonic generation (THG) in LCB crystal were calculated and verified by experiments. The distribution of effective NLO coefficient (deff) and the optimal phase-matching angles for THG with LCB crystal are determined for the first time, with optimal phase-matching angles of (48.7°, 72.5°) and (65.3°, 37.5°) for type-I and type-II THG, respectively. The results show that LCB is an excellent NLO crystal for THG application.

A new quaternary alkali-lanthanide metal tellurate K3LaTe2O9 has been synthesized by a conventional high-temperature solid state method, and single crystals have been grown by spontaneous crystallization. K3LaTe2O9 crystallizes in the hexagonal space group P63/mmc, with a = b = 6.0589(9) Å, c = 15.024(3) Å, and Z = 2. In the structure, [Te2O9]6− contains rare face-sharing TeO6 polyhedra, which are connected by LaO6 octahedra forming a three-dimensional framework structure. Furthermore, its properties are investigated by UV-vis-NIR diffuse reflectance spectroscopy, Raman and IR spectroscopy, thermal analysis, variable-temperature X-ray powder diffraction, and first-principles calculations.

Two nonlinear optical (NLO) crystals based on the 3-phenyl-5-isoxazolone moiety, (Z)-4-(4-(dimethylamino)benzylidene)-3-phenylisoxazol-5(4H)-one (C18H16N2O2, DLS) and (Z)-4-(4-methoxybenzylidene)-3-phenylisoxazol-5(4H)-one (C17H13NO3, MLS), have been successfully grown by a slow evaporation method. The powder second-harmonic generation intensities of DLS and MLS are strong, about 2.8 and 1.5 times that of OH1, respectively. Such a large SHG effect is further elucidated by structure analyses and theoretical calculations. The optical and thermal properties of DLS and MLS have been characterized by UV-vis absorption spectroscopy, IR spectroscopy, thermal gravimetric analysis and differential scanning calorimetry.

•The single crystal of Na2Nd2O(BO3)2 has been obtained for the first time.•It has an extremely high Nd3+ concentration (1.21 × 1022 ions/cm3).•Its absorption and emission spectra have been investigated.•The spectral parameters have also been calculated.•Na2Nd2O(BO3)2 might be a good candidate for microchip laser media.A self-activated crystal Na2Nd2O(BO3)2 has been grown from the Na2O–Nd2O3–B2O3–NaF system. Its structure was determined by single crystal X-ray diffraction, and verified by infrared spectrum and inductively coupled plasma optical emission spectrometry. Na2Nd2O(BO3)2 crystallizes in the monoclinic crystal system, space group P21/c with unit-cell parameters a = 10.804 Å, b = 6.421 Å, c = 10.450 Å, β = 117.95°, Z = 4, and V = 640.4 Å3. Its absorption and emission spectra were measured at room temperature. Based on the absorption spectrum, the spontaneous transition probabilities, fluorescence branch ratio, and the radiation lifetime of 4F3/2 state were calculated. The emission properties under the 355 nm excitation were also evaluated. The electronic structure of Na2Nd2O(BO3)2 was calculated by the first-principles method. The obtained results show that Na2Nd2O(BO3)2 may be a promising microchip laser material.A new self-activated crystal Na2Nd2O(BO3)2 was obtained. It shows a typical Nd3+ optical absorption and strong dual-wavelength emissions after excited at 355 nm.

•The single crystal of Na3Nd9O3(BO3)8 has been obtained for the first time.•It has a extremely high Nd3+ concentration (1.60 × 1022 ions/cm3).•Its absorption spectrum, emission spectrum, and decay time have been investigated.•Na3Nd9O3(BO3)8 might be a good candidate for microchip laser media.A self-activated crystal Na3Nd9O3(BO3)8 has been grown by using Na2CO3–B2O3–NaF as flux. Its structure was determined by single crystal X-ray diffraction. Na3Nd9O3(BO3)8 crystallizes in the hexagonal crystal system, space group P  6¯ 2m with unit-cell parameters a = 8.7611 Å, c = 8.4579 Å, Z = 1, and V = 562.23 Å3, which is isostructural with Na3La9O3(BO3)8. Na3Nd9O3(BO3)8 has a high Nd3+ concentration (1.60 × 1022 ions/cm3), almost three times that of the self-activated crystal NdAl3(BO3)4 (NAB). The absorption and emission spectra as well as decay time for 4F3/2 to 4I11/2 transition in Na3Nd9O3(BO3)8 were measured at room temperature. The obtained results show that Na3Nd9O3(BO3)8 may be a potential high-neodymium-content laser crystal for microchip laser application.

•Tb:LCB crystal with Tb3+ content of 3.76 × 1020 ions/cm3 has been grown.•Absorption and emission spectra were measured and analyzed based on JO theory.•The 5D4–7F5 transition is suitable for the generation of green light at 543 nm.Tb3+ doped La2CaB10O19 (Tb:LCB) crystal with dimensions of 60 × 26 × 22 mm3 has been grown by the top-seeded solution growth (TSSG) method. X-ray powder diffraction (XRPD) analysis shows that the introduction of Tb3+ does not change the structure of LCB crystal. Tb3+ content was determined by inductively coupled plasma optical emission spectrometry to be 3.76 × 1020 ions/cm3. The principal refractive indices of Tb:LCB crystal were accurately measured at room temperature by using the minimum deviation method, and Sellmeier equations were fitted. The unpolarized absorption and emission spectra were measured at room temperature by using X-, Y-, and Z-cut crystals. According to the Judd–Ofelt theory, the spontaneous transition probabilities, fluorescence branch ratio, and radiation lifetime of 5D4 state were calculated. The unpolarized and polarized emission properties under the 368 nm excitation were also evaluated. The decay time of the 543 nm emission corresponding to 5D4–7F5 transition was measured. The experimental results agree well with the calculated ones.

•Four new 1,4-dimethylquinolinium derivatives were successfully obtained.•4HQTMS is a rarely seen acentric 1,4-dimethylquinolinium derivatives crystal.•Detailed study of crystal structures and their packing.Four phenyl-substituted quinolinium salts with different counter anions, C27H27NO4S, C26H25NO5S, C25H22NO5SCl, and C25H22NO5SBr, were synthesized and their single crystals were successfully grown from methanol solution by slow evaporation. Single crystal X-ray diffraction analyses showed that C27H27NO4S crystal belongs to the noncentrosymmetric orthorhombic space group Pna21, and the other three crystals belong to centrosymmetric monoclinic space group P21/n. Their first order hyperpolarization and macroscopic nonlinearity were analyzed and physical properties were characterized by UV–vis absorption spectroscopy, and differential scanning calorimetric and thermal gravimetric analysis.Four new 1,4-dimethylquinolinium crystals were obtained and characterized. Relationship between structures and properties, and the influence of molecular interactions in the structures were discussed in detail.

•Thermal refractive index coefficient expressions were derived for the first time.•Temperature-dependent Sellmeier equations were fitted accurately.•Thermal refractive index coefficients change from positive to negative values.•PM-I directions for THG at different temperatures were calculated and measured.The principal refractive indices of Na3La9O3(BO3)8 (NLBO) crystal in the wavelength range of 0.363–2.325 μm were accurately measured by using the minimum deviation method within the temperature range from 23.5 °C to 160 °C. We derived the expressions of thermal refractive index coefficient as a function of wavelength that could be used to calculate the principal refractive indices at different wavelengths. The temperature-dependent Sellmeier equations were also derived and used to calculate the phase-matching (PM) angles for a frequency conversion device based on NLBO crystal at different temperatures. We found that the thermal refractive index coefficients of NLBO crystal changed from positive to negative values with the increase of wavelength. In addition, the phase matching conditions for third harmonic generation (THG) at different temperatures were also investigated.

CsB3O5 (CBO) single crystals without scattering centers have been successfully grown from the Cs2O–B2O3–MoO3 ternary system by the top-seeded solution growth method. The suitable region for CBO crystal growth was investigated by growth experiments, viscosity and volatility measurements, which confirmed that the optimal molar ratio of Cs2O:B2O3:MoO3 was 2:3:2.5. By carefully controlling growth parameters, including the temperature gradient in the axis, rotation rate, cooling rate, and seed direction, a free of scattering centers CBO crystal with dimensions up to 29 × 31 × 47 mm3 has been obtained. The grown CBO crystals possess high optical quality. The full-width at half-maximum (FWHM) of the rocking curve is 0.0057°, and the optical homogeneity is at the level of 10−6 cm−1. The optical absorption at the critical wavelengths of 1064 and 532 nm was measured to be 200 and 60 ppm cm−1, respectively. The laser-induced damage threshold (LIDT) at λ = 1.064 nm and τ = 5.0 ns is about 4.50 GW cm−2. Moreover, a high-power 278 nm ultraviolet (UV) laser through fourth harmonic generation (FOHG) of a diode-pumped 1112 nm Nd:YAG laser has been demonstrated in CBO crystal for the first time.

Using Na2CO3–H3BO3–NaF as fluxes, transparent RE:Na3La9O3(BO3)8 (abbr. RE:NLBO, RE=Er, Yb) crystals have been grown by the top seed solution growth (TSSG) method. The X-ray powder diffraction analysis shows that the RE:NLBO crystals have the same structure with NLBO. The element contents were determined by molar to be 0.64% Er3+ in Er:NLBO, 2.70% Yb3+ in Yb:NLBO, respectively. The polarized absorption spectra of RE:NLBO have been measured at room temperature and show that both Er:NLBO and Yb:NLBO have a strong absorption bands near 980 nm with wide FWHM (Full Wave at Half Maximum) (21 nm for Er:NLBO and 25 nm for Yb:NLBO). Fluorescence spectra have been recorded. Yb:NLBO has the emission peaks at 985 nm, 1028 nm and 1079 nm and the emission peak of Er:NLBO is at 1536 nm. Spectral parameters have been calculated by the Judd–Ofelt theory for Er:NLBO and the reciprocity method for Yb:NLBO, respectively. The calculated values show that Er:NLBO is a candidate of 1.55 μm laser crystals and Yb:NLBO is a candidate for self-frequency doubling crystal.Fluorescence spectra show the emission peaks at 985, 1028 and 1079 nm of Yb:NLBO and at 1536 nm of Er:NLBO.

A non-centrosymmetric fluoride borate, Ba3Sr4(BO3)3F5, has been synthesized by solid state reaction techniques, and a single crystal was grown by the top-seeded solution growth method using NaF as flux. Single-crystal X-ray diffraction analysis shows the structure to be hexagonal with space group P63mc (No. 186) and the following cell parameters: a = b = 10.8953(16) Å, c = 6.9381(15) Å, and Z = 2. It exhibits an intricate 3-dimensional framework of interconnecting Ba(1)O(1)3O(2)4F(2) polyhedra, Sr(1)O(2)4F(1)2F(3) polyhedra, Sr(2)O(2)6F(1)3F(3) polyhedra, and isolated BO3 triangles. The infrared spectrum indicates that the Ba3Sr4(BO3)3F5 crystal contains characteristic BO33− groups as its basic structural units, which is consistent with the crystallographic study. The transparency spectrum shows that the as-grown crystal is transparent in the wavelength range of 270 to 2550 nm, the highest transmittance exceeds 85%, and the UV cutoff wavelength is about 210 nm.The thermal analysis shows that it is chemically stable and melts congruently at 1174.3 °C.

The optical transmission spectra of BaCaBO3F (abbr. BCBF) crystal have been measured at room temperature. The refractive indices have been measured with the minimum deviation method and fitted to the Sellmeier equations. The nonlinear optical coefficient d22 of BCBF crystal determined by the Maker fringe technique is 0.74d36(KDP).

A series of potassium barium rare earth borates, KBaRE(B3O6)2 (RE = Y, Eu, and Tb), have been synthesized with solid state reaction techniques. Single crystals of the first member of the series, KBaY(B3O6)2, have been grown via spontaneous crystallization. Single crystal X-ray diffraction results show that KBaY(B3O6)2 belongs to the trigonal system, space group R3¯ with cell parameters of a = 7.1677(10) Å, c = 17.588(4) Å, and Z = 3. The nearly planar B3O6 groups serve as the fundamental building units, which are distributed layer upon layer along the c axis. Regular YO6 octahedra and irregular Ba/KO9 polyhedra alternately locate between the B3O6 layers and form YO6 and Ba/KO9 polyhedra layers, respectively. DSC analysis shows that the melting point of KBaY(B3O6)2 is 989 °C, and the X-ray powder diffraction pattern of melted KBaY(B3O6)2 crystal confirms that it melts incongruently. The photoluminescence properties of KBaEu(B3O6)2 and KBaTb(B3O6)2 under UV excitation have also been investigated.Download full-size imageHighlights► Syntheses of new borates KBaRE(B3O6)2 (RE = Y, Eu, and Tb). ► Crystal growth and structure of KBaY(B3O6)2. ► Photoluminescence properties of KBaEu(B3O6)2 and KBaTb(B3O6)2.

•Tb:NLBO crystal with a high Tb3+ content (1.089×1021 ions/cm3) has been grown.•Absorption and emission spectra were measured and analyzed based on JO theory.•Tb:NLBO has a large emission cross-section and quantum efficiency at 543 nm.•The 5D4–7F5 transition is suitable for the generation of green light at 543 nm.Tb3+ doped Na3La9O3(BO3)8 (Tb:NLBO) crystals have been grown by the top-seeded solution growth (TSSG) method. X-ray powder diffraction results show that the introduction of Tb3+ does not change the structure of NLBO crystal. Tb3+ concentration was determined by inductively coupled plasma optical emission spectrometry to be 1.089×1021 ions/cm3. The absorption and emission spectra were measured at room temperature by using a (1 0 0) oriented crystal wafer. According to the Judd–Ofelt theory, the spontaneous transition probabilities, fluorescence branch ratio, and the radiation lifetime of 5D4 state were calculated. The unpolarized and polarized emission properties under the 367 nm excitation were evaluated. The decay time of the 543 nm emission assigned to the 5D4–7F5 transition was also measured. All the results show that Tb:NLBO crystal would be a promising green laser material.

•Pr3+ doped NLBO crystal with sizes of 45×30×15 mm3 has been obtained.•The transitions at about 482, 593, and 635 nm exhibit large branch ratio.•The mean lifetime (55.81 ns) is longer than that of Pr3+:LaB3O6 (28 ns).Pr3+ doped Na3La9O3(BO3)8 (Pr3+:NLBO) crystals were grown by the top-seeded solution growth (TSSG) method. Powder X-ray diffraction results show that the introduction of Pr3+ does not change the structure of NLBO crystal. Pr3+ concentration was determined to be 1.21×1021 ions/cm3 by inductively coupled plasma optical emission spectrometry. The refractive index was measured by using the minimum deviation method, and Sellmeier equations were fitted. The absorption and emission spectra were measured at room temperature with a (100) oriented crystal wafer. The unpolarized and polarized emission properties under the 450 nm excitation were evaluated. The decay time of the 498 nm emission assigned to the 3P0–3H4 transition was also measured. The spectroscopic parameters were calculated, which are consistent with the experimental results. The results indicate that Pr3+:NLBO crystal might be a promising laser material.

A new noncentrosymmetric borate, Na3Y3(BO3)4, was grown in the Na2O–B2O3–NaF flux system. Its open-framework structure features a large hexagonal tunnel (5.92 Å in diameter), which is extremely rare in borates. First-principles calculations on its kinetic stability and optical properties were performed.

A new quaternary alkali-lanthanide metal tellurate K3LaTe2O9 has been synthesized by a conventional high-temperature solid state method, and single crystals have been grown by spontaneous crystallization. K3LaTe2O9 crystallizes in the hexagonal space group P63/mmc, with a = b = 6.0589(9) Å, c = 15.024(3) Å, and Z = 2. In the structure, [Te2O9]6− contains rare face-sharing TeO6 polyhedra, which are connected by LaO6 octahedra forming a three-dimensional framework structure. Furthermore, its properties are investigated by UV-vis-NIR diffuse reflectance spectroscopy, Raman and IR spectroscopy, thermal analysis, variable-temperature X-ray powder diffraction, and first-principles calculations.