Two novel vanadogermanates [Cd(en)(H2O)2][Cd(en)2][Cd(en)]{[Cd(en)]2[Ge8V12O42.5(OH)5]}·2H2O (1) and [Cd(en)3][Cd(en)]2{[Cd(en)]2[Ge8V12O42(OH)6]}·10H2O (2, en = ethylenediamine) have been hydrothermally synthesized and structurally characterized by elemental analysis, infrared spectroscopy, powder X-ray diffractions, thermogravimetric analysis, UV–vis spectroscopy, and single-crystal X-ray diffractions. Structural analysis reveals that the Ge–V–O cluster anions in the two compounds are derived from the classical saturated {V18O42} cluster by replacing four VO5 square pyramids with four Ge2O7 groups. Especially, the Ge–V–O cluster anion in 2 is a new configuration of Ge–V–O clusters with four Ge2O7 groups and first reported in this work. 1 is the first 1-dimensional (1-D) chain based on the linkage of centrosymmetric dimeric clusters {[Cd(en)]2[Ge8V12O42.5(OH)5]}212– and trinuclearity [Cd3O4(en)4(H2O)2]2– complexes. 2 is an unprecedented 2-D network built from unique {[Cd(en)]2[Ge8V12O42(OH)6]}8– clusters and 1-D coordination chains {Cd3O2(en)5}2+. Magnetic measurements illustrate that these compounds have overall antiferromagnetic exchange interactions between metal ions.

•Li2Eu4(MoO4)7 phosphor was synthesized by a sol-gel method for the first time.•The chromaticity coordinate of Li2Eu4(MoO4)7 (0.6497, 0.3499) is better than that of Y2O2S:Eu2+ (x = 0.63, y = 0.35).•The Li2Eu4(MoO4)7’s decay lifetime is shorter than LiGd(MoO4)2:Eu3+, KLu(MoO4)2:Eu3+ and Y2O3:Eu3+ phosphors’.A series of red light-emitting phosphors Li2Y4-x(MoO4)7:xEu3+ were synthesized by a sol-gel method. These samples were characterized by DSC-TGA, XRD, PL and FE-SEM analysis. The best dosage of citric acid is four times of metal ions. The optimal sintering temperature is 900 °C. The luminescence intensity of Li2Y4-x(MoO4)7:xEu3+ are strongest when the doping concentration of Eu3+ is 4 mol. These phosphors can be excitated by near-UV light of 395 nm and blue light of 465 nm effectively, and show strong red light at 615 nm, which is corresponding to 5D0 → 7F2 transition of Eu3+ ion. The CIE chromaticity coordinates of Li2Eu4(MoO4)7 phosphor is calculated to be (0.6497, 0.3499), and its lifetime is 0.38 ms. The results show that the phosphor is a promising red component candidate for near-UV and bule LED application.

•The optical properties of naphthalene diimides can be tuned by a facile cocrystal approach.•Five naphthalene diimide cocrystals with different optical properties were obtained.•The supramolecular structures of these five naphthalene diimide cocrystals were studied.•The contributions of non-covalent interactions were evaluated.•The π–π interactions are demonstrated to be a key factor for the optical properties.Core-substituted naphthalene diimides are attracting much interest because of their tunable optical properties, which are generally achieved by the elaborate introduction of electron-donating groups into electron-deficient core to form donor–acceptor compounds through the covalent bonds. Here we report that the optical properties of core-unsubstituted naphthalene diimides can be modulated by a facile cocrystal strategy. Based on the X-ray crystallographic and Hirshfeld surface analyses, the π–π interactions have been demonstrated to be the most important factor that answers for the optical properties of naphthalene diimide cocrystals, while other interactions, such as hydrogen bonds and solvation effects, have little impact on their properties but influence π stacking. This insight is of considerable significance for the development of naphthalene diimide based materials in various directions.

Ca3R2–xWO9:xEu3+ (R=Y, Gd) red-emitting phosphors were prepared by solid state reactions. These samples were characterized by differential scanning calorimetry and thermogravimetry analysis (DSC-TGA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), photoluminescence (PL) and field emission scanning electron microscopy (FE-SEM) analyses. The optimum sintering temperature for these phosphors was 1100 °C, and the optimum sintering time was 2 h. The optimum doped concentration of Eu3+ in Ca3Y2–xWO9:xEu3+ and Ca3Gd2–xWO9:xEu3+ were x=1.5 and x=1.1, respectively. These phosphors could be excited by near-UV light of 394 nm and blue light of 465 nm, and showed strong red emission line at 612 nm (5D0→7F2), which indicated that Ca3R2–xWO9:xEu3+ (R=Y, Gd) were promising red candidates for white LED.Excitation and emission spectra of CaY0.5W:1.5Eu3+ (a) and CaGd0.9W:1.1Eu3+ (b)

•TbVO4 crystals were grown by the Czochralski method under different growth atmosphere.•TV crystal grown at N2 + CO2 mixed atmosphere has high transmittance at 600–1500 nm waveband.•TbVO4 crystal has larger Verdet constants than those of TGG crystal.TbVO4 (TV) single crystals with dimensions of 18 × 18 × 16 mm3 were grown by Czochralski method under different atmosphere. XPS studies revealed the presence of V4+ and Tb4+ in TV crystal grown at 99.9% N2 atmosphere, which caused a wide absorption peak centered at 950 nm in the transmission spectrum. TV crystal grown at 80% N2 + 20% CO2 mixed atmosphere has high transmittance at 600–1500 nm waveband. Faraday rotation spectra of TV crystal were measured. TV crystal has a larger Faraday rotation than terbium gallium garnet (TGG) crystal at 500–1500 nm waveband.

•Sr2Tb8(SiO4)6O2 (STS) crystals were grown by the Czochralski method.•The magnetic property was characterized by magnetic susceptibility from 2 to 300 K.•STS crystal shows a higher visible transparency than Tb3Ga5O12 (TGG).•STS crystal exhibits superior magneto-optical properties.•The Verdet constants of STS crystal are between 65% and 75% larger than those of TGG.Sr2Tb8(SiO4)6O2 crystals have been grown and investigated for the first time for magneto-optical applications. The X-ray powder diffraction confirms that the compound crystallizes in the hexagonal system, with a common oxyapatite structure. The as-grown crystal exhibits low thermal expansion anisotropy (αa/αc ≈ 1.1), and the hardness is about 5.0 Moh. The temperature dependence of the magnetic susceptibility indicated that the Sr2Tb8(SiO4)6O2 crystal exhibits paramagnetic behavior over the experimental temperature-range 2–300 K. The present investigations demonstrate that Sr2Tb8(SiO4)6O2 crystals show a higher visible transparency and a larger Faraday rotation than terbium gallium garnet (TGG) crystals. Sr2Tb8(SiO4)6O2 is therefore a very promising material in particular for new magneto-optical applications in the visible–near IR wavelength region.

•Dy2Ti2O7 single crystal was grown by the Czochralski method.•As-grown crystal adopt face-centered cubic lattice.•Dy2Ti2O7 has a low absorption coefficient at 600–760 nm.•The Verdet constant of Dy2Ti2O7 at 633 nm is 40% larger than that of Tb3Ga5O12.A pyrochlore crystal with magneto-optical effect – Dy2Ti2O7 crystal with 19–20 mm in diameter and 21 mm in length has been grown by the Czochralski method. The lattice parameters were calculated by X-ray powder diffraction, which revealed that the crystal belongs to cubic system. Absorption spectrum was measured in the visible and near-infrared region at room temperature, which indicated the crystal has low absorption coefficient at 600–760 nm. The specific Faraday rotation of single crystal was measured at room temperature in 532, 633, and 1064 nm. The Verdet constant of Dy2Ti2O7 crystal at 633 nm comes up to −183 rad/(m T), which is as 1.4 times as that of TGG reported.

The large bandgap of ZnO limits its application in photovoltaic devices, thus the semiconductor quantum dots (QDs), such as CdSe, is utilized to improve light-harvesting efficiency of solar cells. The CdSe@ZnO flower-rod core–shell nanocable arrays (CSZFRs) are prepared with a simple ion exchange method from aqueous solutions. The optical absorptions of the nanocable arrays can be controllably tuned to cover almost the entire visible spectrum (>750 nm) via quantum dots (QDs) sensitized attributed to the smaller band gap of CdSe. Moreover, a typical type II band alignment enhance the separation of photogenerated charge carriers, and reduce the electron–hole recombination within CSZFRs, demonstrated by the photoluminescence (PL) quenching after the formation of CSZFR hybrid structures. In addition, the CdSe-sensitized ZnO nanostructures demonstrate broad external quantum efficiency (EQE) in the spectrum from 300 to 740 nm. Therefore, the CSZFRs nanocable heterostruture exhibits a photovoltaic performance with a higher open-circuit photovoltage (−0.93 VAg/AgCl) and short-circuit photocurrent (1.00 mA cm−2).Graphical abstractHighlights► The CdSe@ZnO flower-rod core–shell nanocable arrays are used as photoanode. ► The photoanode of CdSe@ZnO nanocable exhibits higher photovoltaic performance. ► Ion exchange is a facile method to prepare the CdSe@ZnO nanocable. ► The CdSe-sensitized ZnO nanocables demonstrate a broad EQE in visible spectrum.

Li2Y4–xEux(WO4)7–y(MoO4)y red-emitting phosphors were synthesized by solid state reaction and characterized by powder X-ray diffraction (XRD) and photoluminescence (PL) spectrum. The excitation spectra showed that the phosphors could be efficiently excited by near-UV light of 395 nm. When the relative molar ratio of Mo/W was 7:0, and the optimum doped concentration of Eu3+ was 2.8 mol, the phosphor showed strong red emission lines at 615 nm corresponding to the forced electric dipole 5D0→7F2 transition of Eu3+. Compared with Na2Y2Eu2(MoO4)7 and K2Y2Eu2(MoO4)7, the fluorescence intensity of Li2Y1.2Eu2.8(MoO4)7 phosphor was the strongest. The CIE chromaticity coordinates of Li2Y1.2Eu2.8(MoO4)7 phosphor was calculated to be (0.66, 0.34).Emission spectra (λex=395 nm) of Li2Y1.2Eu2.8(WO4)7–y(MoO4)y phosphors with different WO42– doping ratios (y=0, 0.7, 1.4, 2.1, 2.8, 3.5, 4.2, 4.9, 5.6, 6.3, 7.0) (a) and Li2Y4–xEux(MoO4)7 phosphors with different Eu3+ doping ratios (x=0.4, 0.8, 1.2, 1.6, 2.0, 2.4, 2.8, 3.2, 3.6, 4.0) (b)

Li2Tb4(MoO4)7 crystal with sizes of ∅20 × 26 mm was grown by the Czochralski method. X-ray powder diffraction was carried out and the lattice parameters were calculated, which showed that the single crystal belongs to tetragonal system. Absorption spectrum in the wavelength range of 400–1600 nm and weak absorption at 1064 nm were measured, which indicates the crystal has low absorption coefficient at 600–1500 nm regions. The Verdet constant of Li2Tb4(MoO4)7 crystal at 532 nm comes up to −347 rad/m T, which is as 1.8 times as that of TGG reported.Highlights► Li2Tb4(MoO4)7 crystal was grown by the Czochralski method. ► Li2Tb4(MoO4)7 crystal has larger Verdet constants than those of TGG crystal. ► Li2Tb4(MoO4)7 crystal may be a candidate material for magneto-optical devices.

Li2MoO4·1.8Tb2(MoO4)3 crystal, a kind of solid solution crystal, was grown in air by the top seeded solvent growth method in a Li2Mo2O7 flux. The lattice parameters of the crystal were determined by X-ray diffraction analysis. The absorption coefficient of the crystal was investigated at wavelengths from 400 to 1500 nm at room temperature. Valence states of Tb ions in Li2MoO4·1.8Tb2(MoO4)3 crystal were analyzed by X-ray photoelectron spectroscopy measurement. Verdet constants for the Li2MoO4·1.8Tb2(MoO4)3 crystal at 532, 633 and 1064 nm wavelengths were measured by the extinction method. They are −341, −239 and −75 rad m−1 T−1, respectively. The results show that the crystal has a larger magneto-optical figure of merit than terbium gallium garnet at wavelength of 633 nm.

Two new Mn(II) coordination polymers, [Mn15(atz)18(μ3-OH)4(μ3-SO4)4]n·9nH2O (1) and [Mn8(atz)4(μ-OH)4(μ4-SO4)4(H2O)4]n·nH2O (2) (atz = 5-aminotetrazolate), have been prepared under similar hydrothermal conditions except the difference of the source of the atz ligand. They were characterized by single-crystal X-ray diffraction studies, variable temperature (1.8−300 K) magnetic measurements, and thermal gravity analysis. The results of X-ray crystallographic analysis reveal that compound 1 is a 3D coordination polymer with a (3,4)-connected (83)4(86)3 topology, which is built from trinuclear [Mn3(μ3-SO4)(μ3-OH)] clusters and bridging mononuclear Mn centers. In compound 2, it contains a 3D inorganic cationic [Mn8(μ3-OH)4(μ4-SO4)4]n4+ network with an unprecedented (4,6)-connected topological net, the Schläfli symbol of which is (33·82·9)2(36·84·95). The inorganic cationic net is templated by the atz ligands to form a microporous framework with hydrophilic channels. The variable temperature magnetic data indicate that 1 exhibits antiferromagnetic behavior, whereas 2 shows ferrimagnetic behavior.

A new coordination polymer, [Cd4(atz)6(PTA)]n has been firstly synthesized by employing mixed-ligand of terephthalic acid (PTA) with the in-situ generated ligand of 5-amino-tetrazolate (atz−). Compound 1 represents a 3D microporous framework constructed from Cd-tetrazolate subunits and the subunits are bridged by PTA and atz ligands. When the subunit was collided into node, compound 1 possesses an unprecedented 3, 9-connected topological network. Furthermore, the investigations of thermal stability and luminescent property of complex 1 indicate that compound 1 may be an excellent candidate for potential blue-light emitting material.A new coordination polymer, [Cd4(atz)6(PTA)]n has been firstly synthesized by employing mixed-ligand synthetic approach. Compound 1 presents a 3D microporous framework with an unprecedented 3, 9-connected topological network.

Five Cd(II) coordination polymers with the in situ generated ligand 5-amino-tetrazolate (atz−) were prepared from the hydrothermal reactions of the corresponding Cd(II) salts, and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis (TGA) and single crystal X-ray diffraction. The results of X-ray crystallographic analysis revealed that compounds {[Cd5(atz)9]Cl}n·2nH2O (1) and {[Cd5(atz)9](SO4)0.5}n·2nH2O (3) are isostructural with the perfect Kagome layers bridged by [Cd2(μ4-atz)3] clusters to generate a three-dimensional (3D) rare lon (topological type symbol) topological network with a vertex symbol of 66. Its hexagonal channels are filled by Cl− or SO42− anions and water molecules. Compound [Cd5(atz)8(μ2-Cl)2]n·3nH2O (2) contains three different kinds of bridging modes of the atz− anion and is an intricate 3D polymer. It possesses a 5,6-connected btv topology with a vertex symbol of (47·62·8)2(410·65), which is rarely observed but only predicted by O’Keeffe in theory in coordination polymers. Compound [Cd7.5(atz)9(μ3-SO4)2(μ3-OH)2]n·4.5H2O (4) is a 3D coordination polymer with a 3,4-connected (83)4(86)3 topology, which is built from trinuclear [Cd3(μ3-SO4)(μ3-OH)] clusters and bridging mononuclear Cd centers. Compound [Cd5(atz)4(μ5-SO4)2(μ3-OH)2]n (5) is constructed by a 3D inorganic cationic [Cd5(μ5-SO4)2(μ3-OH)2]n4+ network, a 6-connected pcu topology, templated by atz− anions. The anion-exchange experiments were performed successfully for 1 and 3. Moreover, the thermal stabilities and photoluminescent properties of these compounds were investigated. This work markedly indicates that the subtle changes in the synthesis conditions profoundly influence the structures and topologies of the products.

Three new metal–organic frameworks, [Zn(atz)(nic)]n(1), [Zn(atz)(isonic)]n·nHisonic(2) and [Cd(atz)(isonic)]n(3) (Hnic=nicotinic acid, Hisonic=isonicotinic acid), have been firstly synthesized by employing mixed-ligand of pyridinecarboxylate with the in situ generated ligand of 5-amino-tetrazolate(atz−), and characterized by elemental analysis, IR spectroscopy, TGA and single crystal X-ray diffraction. The results revealed that 1 presents a two-dimensional (2D) “sql” topological network constructed from the linear chain subunit of Zn(nic)2 and atz− ligand. A remarkable feature of 2 is a 2-fold interpenetrated diamondoid network with free Hisonic molecules locating in the channels formed by the zigzag chain subunits of Zn(isonic)2. Complex 3 is a 3D non-interpenetrated pillared framework constructed from the double chain subunits of Cd–COO−–Cd. It possesses a rarely observed (4,6)-connected “fsc” topology. The thermal stabilities and fluorescent properties of the complexes were investigated. All of these complexes exhibited intense fluorescent emissions in the solid state at room temperature.Three new mixed-ligand d10 metal complexes have been synthesized by employing mixed-ligand synthetic approach. Complex 1 presents a 2D “sql” topological network. Complex 2 is a 2-fold interpenetrated diamondoid network with microporous channels. Rarely observed (4,6)-connected “fsc” topological network was found in complex 3.

The Ca0.08Gd0.92VO4 crystal and Nd-doped Ca0.08Gd0.92VO4 crystals were grown by the Czochralski method; the lattice parameters of the crystals were determined by XRD. The results showed that substituting Nd3+ caused an increase in lattice parameter; the segregation coefficient of Nd3+ ions in the crystal is lower than that of Nd:GdVO4 crystal; the absorption spectra, fluorescence spectra, absorption cross-section and the emission cross-section of the Nd:Ca0.08Gd0.92VO4 crystal were investigated at room temperature; furthermore, the Raman performance of Ca0.08Gd0.92VO4 crystal was improved.

A study was made on effect of niobium on the GdVO4 crystal structure. Yb:GdV0.995Nb0.005O4 crystals were grown by the Czochralski method, and their transmission spectra, absorption spectra, and fluorescence spectra were measured. The GdV0.995Nb0.005O4 crystals acting as new laser host crystals do not affect the absorption of Yb3+. Some spectrum parameters calculated by the Fuchbauer—Ladenburger method indicate that doping of Nb5+ in the GdVO4 crystal improves the spectroscopic properties of Yb3+.

•Single crystals of Gd2Ti2O7 with large dimensions have been grown by Czochralski method.•GTO crystal that grown along the [111] direction has an octahedral morphology.•The color of as-grown GTO crystals is sensitive to the oxygen concentration in growth or post-annealing atmosphere.Gd2Ti2O7 (GTO) single crystals having dimensions of 17×17×20 mm3 were grown by the Czochralski method. These crystals displayed a strong growth habit with {1 1 1} facets. The colors of the as-grown crystals were sensitive to the oxygen concentration both during growth and post-growth annealing. The possible reason for the different colors is discussed and based on transmission, energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and electron spin resonance (ESR) analyses.

•Tb9.33(SiO4)6O2 crystals were grown by the Czochralski method.•Structure refinement confirms that the compound crystallizes in the hexagonal system.•Tb9.33(SiO4)6O2 shows a higher visible transparency than Tb3Ga5O12.•The Verdet constant of Tb9.33(SiO4)6O2 is about 2.0 times as large as that of Tb3Ga5O12.Tb9.33(SiO4)6O2 crystals have been grown by the Czochralski technique for the first time for magneto-optical applications. Rietveld structure refinement of XRD data confirms that the compound crystallizes in the hexagonal system P63/m, with oxyapatite structure. Transmittance spectra and the Faraday rotation have been investigated, which demonstrate that Tb9.33(SiO4)6O2 crystals show a higher visible transparency and a larger Faraday rotation than Tb3Ga5O12 crystals. Tb9.33(SiO4)6O2 is therefore a promising material in particular for new magneto-optical applications in the visible-near IR wavelength region.

•Na2Tb4(MoO4)7 crystals were grown by the Czochralski method.•The magnetic property was characterized by magnetic susceptibility from 2 to 300 K.•Na2Tb4(MoO4)7 shows a high transparency from 600 nm to 1500 nm.•The Verdet constant of Na2Tb4(MoO4)7 is about 1.6 times as large as that of Tb3Ga5O12.Na2Tb4(MoO4)7 crystals have been grown by the Czochralski technique for the first time for magneto-optical applications. Structure refinement of XRD data confirms that the compound crystallizes in the tetragonal system I41/a, with scheelite structure. The as-grown crystal exhibits moderate thermal stability and weak thermal expansion anisotropy (αc/αa≈1.08), and the hardness is about 4.7 Moh. Transmittance spectra indicated that the Na2Tb4(MoO4)7 crystal presents a high transparency from 600 nm to 1500 nm after annealing in O2 atmosphere at 973 K for 20 h. The Faraday effect and the temperature dependence of the magnetic susceptibility have been investigated, which demonstrate that the Na2Tb4(MoO4)7 crystal exhibits paramagnetic behavior over the experimental temperature-range 2–300 K and yields a Faraday rotation which is about 1.6 times as large as that of Tb3Ga5O12 crystal. Na2Tb4(MoO4)7 crystal is therefore a promising Faraday material in particular for new magneto-optical applications in the visible–near IR wavelength region.