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A novel 3D Zn-based coordination polymer (NH 2 -LCU-110 , LCU names Liaocheng University) with the formula [Zn(L1)(bpea) n (H 2 L1 ​= ​2-aminoterephthalic acid, bpea ​= ​1,2-bis(4-pyridyl)ethane), was hydrothermally synthesized from a flexible nitrogen-containing carboxylic acid ligand with various coordination modes as main ligands and nitrogen-containing auxiliary ligand with different structures. NH 2 -LCU-110 demonstrates an interesting 5-fold interpenetrating diamond structure. Luminescence measurements reveal that this complex has obvious emission enhancement and quenching towards Al3+ and Cu2+, respectively. The mixed matrix membranes (MMMs) incorporating NH 2 -LCU-110 and poly(methyl methacrylate) (PMMA) as well as simple test papers were both prepared for potential application. The MMMs can quickly detect Al3+ and Cu2+ and the original emission could be regenerated by lifting from the analytical solutions, demonstrating its fast response and good selectivity. The sensing mechanism was investigated in details by various measurements and compared with isostructural complex LCU-110 without –NH 2 groups. All observations indicate that introduction of Lewis basic –NH 2 groups can enhance the intermolecular interactions between the frameworks of coordination polymers and sensing analytes (Al3+ and Cu2+). An amino-functionalized coordination polymer NH 2 -LCU-110 exhibits luminescence turn-on/off toward Al3+/Cu2+, and its mixed matrix membranes and test papers were prepared. [Display omitted] • An amino-functionalized coordination polymer was employed as a multiresponsive luminescence sensor. • NH 2 -LCU-110 exhibits luminescence turn-on and turn-off behavior toward Al3+ and Cu2+, respectively. • Mixed matrix membranes (MMMs) and test papers made the detection more simple and convenient. [ABSTRACT FROM AUTHOR]

Multistimuli responsive materials based on the viologen coordination polymers have attracted much interest in the past few years due to the increasing demand for smart materials. In this paper, based on a viologen ligand 1-(3-carboxybenzyl)- 4,4′-bipyridinium chloride (Hcbbpy) and zinc(II) ion, a new crystalline complex, namely, {[Zn(cbbpy)Cl 2 ]·H 2 O} n (1) has been designed and synthesized. In complex 1 , every cbbpy ligand as a bridge links two Zn2+ ions via carboxylate O atom and pyridine N atom to extend to a 1D zigzag chain. The 1D chains are extended to 3D supramolecular structure through π···π stacking and hydrogen bonding. More importantly, 1 exhibits fast photochromic behaviors in response to UV and X-ray due to the formation of viologen radicals. Complex 1 also shows photo-modulated luminescence property in the solid state. In addition, complex 1 can be deposited on filter paper and displays the potential application as inkless print material. [Display omitted] • A new viologen complex was successfully synthesized and characterized. • Complex 1 shows fast response to UV light and X-ray irradiation. • Complex 1 can be deposited on filter paper and displays as inkless print material. [ABSTRACT FROM AUTHOR]

The encapsulation of photoactive guests into a metal-organic framework is advantageous in endowing extra functionalities such as photochromism and photoswitchable luminescence. In this paper, a host-guest MOF material, [Zn 3 (IPA) 4 ​MV] (1) (H 2 IPA ​= ​isophthalic acid, MV·2NO 3 ​= ​1,1'-dimethyl-(4,4'-bipyridine)-1,1'-diium dinitrate) has been constructed by encapsulating simplest methyl viologen guest into the anionic MOF framework. This material exhibits reversible naked-eye detectable photochromic properties varying from colorless to blue upon UV–Vis light irradiation. The MV2+ and the short O⋯N distance between the oxygen atom and pyridine ring of MV2+ play a crucial role in the photochromism of this compound. This host-guest MOF compound shows photoswitchable luminescent properties in the solid state. More interestingly, this host-guest MOF material can be deposited on filter paper and can be employed as inkless print material by controlling the UV–Vis light irradiation with the stencil. A novel MOF-based host-guest compound was prepared by incorporating the photoactive methyl viologen into the anionic framework, which exhibit photochromism upon UV–Vis light irradiation and photocontrolled luminescence. Moreover, this compound can be used as inkless and erasable print media. [Display omitted] • A host-guest compound was prepared by incorporating the viologen into the anionic MOFs. • Compound 1 exhibits fast-responsive photochromism and reversible luminescence switching upon UV–Vis light irradiation. • Compound ​ 1 ​can be employed as inkless and erasable print media by controlling the UV-Vis light irradiation. [ABSTRACT FROM AUTHOR]

In this paper, we have presented the comprehensive characterization of red-light-emitting novel β-BaB 2 O 4 : x Sm3+ (x = 0.5, 0.75, 1, 1.5, and 2 mol%) phosphor samples synthesized by making use of solid-state reaction method. The XRD patterns verified the successful synthesis and in-depth analyses were carried out to explore the structural, luminescence, and thermal properties. Notably, the introduction of Sm3+ through doping did not result in any substantial alterations in the crystal structure. Photoluminescence (PL) emission spectra exhibited 4 distinct peaks for 401 nm excitation. Out of these 4 peaks, the prominent peak was present at 601 nm, attributed to the magnetic dipole-allowed transition 4G 5/2 → 6H 7/2. The colorimetric analysis revealed the correlated color temperature (CCT) to be around 1700 K, accompanied by 99.9 % colour purity. The optimal doping concentration, before luminescence quenching, was identified as 1 mol%, with multipole-multipole interactions identified as the predominant quenching mechanism. Diffuse reflectance spectroscopy (DRS) studies on β-BaB 2 O 4 :1%Sm3+ confirmed characteristic peaks corresponding to Sm3+ transitions, revealing an ionic bonding nature between Sm3+ and the host. Also, the direct optical band gap was determined to be 5.62 eV. Furthermore, the optimized phosphor demonstrated exceptional temperature-dependent photoluminescent (TDPL) properties, exhibiting a negligible (∼5 %) decrease in emission intensity for prominent peaks even at 440 K. Overall, the phosphors displayed high activation energy, significant thermal stability, and thermal sensing properties, making them promising candidates for various optoelectronic applications. [Display omitted] • Sm3+ doped -BaB 2 O 4 phosphors have been successfully synthesized via solid-state reaction method. • XRD and FTIR revealed that the structural properties of the phosphor were not affected by the doping. • The prepared phosphor exhibited reddish-yellow emission and excellent temperature-dependent PL spectra. • Optimally optimized phosphor was thermally stable and exhibited TDPL spectra up to a temperature of 443 K. • Due these features, the phosphor is a worthy candidate for light emission, WLED, and thermal sensing applications. [ABSTRACT FROM AUTHOR]

In this paper, Short-time X-ray irradiation induced long afterglow and photostimulated luminescence from Sr 2 GeO 4 : Pr3+ has been observed. Under the X-ray irradiation, Sr 2 GeO 4 : Pr3+ can produce long afterglow and photostimulated visible luminescence mainly located at 490, 547 and 629 nm, which are attributed to 3P 0 →3H 4 , 3P 0 →3H 5 and 3P 0 →3H 6 of Pr3+, respectively. More important, even 5 s X-ray irradiation which was less than the X-ray damage from one CT scan, can induce 5400 s afterglow emission. Furthermore, due to its excellent photostimulated luminescence properties, the afterglow emission intensity of Sr 2 GeO 4 : Pr3+can be significantly improved under the radiation of 980 and 808 nm lasers and the emission intensities can still be maintained even after 12 testing cycles. The thermoluminescence results show that Pr3+ doping produces three different traps. Among these, the traps with 0.64 and 0.71 eV trap depth result in excellent X-ray long afterglow luminescence of Sr 2 GeO 4 : Pr3+. While the deep trap of 0.96 eV determines the photostimulated luminescence properties. These results indicate that Sr 2 GeO 4 :Pr3+ possesses excellent long afterglow and photostimulated luminescence under the X-ray irradiation in safety range, which thus can be regarded as in vivo light source to efficiently conduct photodynamic therapy in the future. Sr 2 GeO 4 :Pr3+ long afterglow material has been prepared, which has the characteristics of Short-time irradiation by X-ray induced long afterglow and photostimulated luminescence. The result showed that the afterglow emission peaks are mainly located at 490 nm, 547 nm and 629 nm, corresponding to the 3P 0 →3H j (j = 4, 5, 6) characteristic transitions of Pr3+, respectively. When the doping concentration of Pr3+ is 0.5 %, the sample possesses the best afterglow and the afterglow emission can still be observed after 5400 s. And the X-ray excitation can produce much better afterglow performance than 254 nm excitation. In addition, the sample also showed good afterglow performance under short-time (5 s) X-ray radiation. At the same time, the sample possesses strong PSL characteristics under the excitation of 980 nm and 808 nm lasers and still maintains strong PSL afterglow intensity after 12 cycles of measurements. Furthermore, the trap density under X-ray excitation is much higher than that under UV excitation, which thus produce much longer afterglow emission under the X-ray irradiation. These results indicate that Sr 2 GeO 4 :Pr3+ possesses excellent long afterglow and photostimulated luminescence under the X-ray irradiation in safety range, which thus can be regarded as in vivo light source to efficiently conduct photodynamic therapy in the future. [Display omitted] • X-ray induced long afterglow material Sr 2 GeO 4 :Pr3+ shows excellent photostimulated luminescence properties. • Sr 2 GeO 4 :Pr3+ showed good afterglow performance under short-time (5 s) X-ray radiation. • A model is presented to clarify the afterglow mechanisms of Sr 2 GeO 4 :Pr3+. [ABSTRACT FROM AUTHOR]

High-efficiency phosphor with excellent luminescence properties and thermal stabilities is essential for phosphor-converted white light-emitting diodes (w-LEDs). Compared with red and green phosphors, near-ultraviolet excited blue phosphors with high efficiency and excellent thermal stability are still scarce, and the development of efficient blue phosphors remains challenging. NaLi 3 SiO 4 : Eu2+ (NLSO: Eu2+) is a promising narrow-band blue phosphor. In this paper, a series of Na 1-y K y Li 3 SiO 4 : 5%Eu2+ (0.05 ≤ y ≤ 0.2) phosphors were successfully synthesized by high-temperature solid-state reaction through co-doping a small amount of K+ ions in the matrix, significantly improving their luminescence property and thermal stability. Because of the weaker electronegativity of K+ ions, the emission peaks of Na 1-y K y Li 3 SiO 4 : 5%Eu2+ were slightly blue-shifted from 467 to 463 nm compared with those of NLSO: Eu2+. With an increase in the number of K+ ions, the luminescence intensity of the phosphors increased. When the content of the K+ ion reached 0.2, the luminescence intensity of the Na 0.8 K 0.2 Li 3 SiO 4 : 5%Eu2+ (NKLSO: 5%Eu2+) phosphor reached its maximum. Compared to the NLSO: 5%Eu2+ phosphor, the luminescence intensity increased by approximately 300 %. At 150 °C, the luminescence intensity of NLSO: 5%Eu2+ phosphor was retained at 75.98 % compared with room temperature, while the NKLSO: 5%Eu2+ phosphor maintained a luminescence intensity of 84.36 % relative to room temperature, demonstrating excellent thermal stability. The enhanced luminescence performance of the NKLSO: Eu2+ phosphor makes it a promising high-efficiency blue phosphor for phosphor-converted w-LEDs. Through co-doping a small amount of K+ ions into the NaLi 3 SiO 4 : Eu2+, significantly improving the luminescence property and thermal stability. [Display omitted] • A series of Na 1-y K y Li 3 SiO 4 : 5%Eu2+ (0.05 ≤ y ≤ 0.2) phosphors were successfully synthesized through co-doping K+ ions in the matrix. The weaker electronegativity of K+ ions makes it easier for Eu3+ to be reduced to Eu2+. • In luminescence properties, when the content of the K+ ion reached 0.2, the luminescence intensity of the Na 0.8 K 0.2 Li 3 SiO 4 : 5%Eu2+ phosphor reached its maximum. Compared to the NaLi 3 SiO 4 : 5%Eu2+ phosphor, the luminescence intensity increased by approximately 300 %. • The Na 0.8 K 0.2 Li 3 SiO 4 : 5%Eu2+ exhibited superior thermal stability compared to NaLi 3 SiO 4 : 5%Eu2+. The luminescent intensity of NaLi 3 SiO 4 : 5%Eu2+ at 150 °C remains 75.98 % of the room temperature intensity, while the luminescent intensity of Na 0.8 K 0.2 Li 3 SiO 4 : 5%Eu2+ is significantly increased to 84.36 %. • The narrowband blue phosphor Na 0.8 K 0.2 Li 3 SiO 4 : 5%Eu2+ is a potential candidate for n-UV excited w-LEDs applications because of its excellent luminescence properties. [ABSTRACT FROM AUTHOR]

Organic amines are ubiquitous and essential in the dye, polymer, and pharmaceutical industries, but can also be highly corrosive and toxic. Developing a quick and efficient method to detect organic amines is an important challenge. In this paper, we demonstrate the detection of organic amines by colorimetric and luminescence sensing of an electron-deficient viologen metal organic material. The material, comprising 1-(3,5-dicarboxyphenyl)-4,4′-bipyridinium and Cd(II), possesses a two-dimensional framework with viologen-lined chromophores and accessible electron-deficient viologen moieties constituting Lewis acidic sites. It exhibits reversible photochromic behavior under UV–Vis light irradiation and a visual color change and fluorescence quenching upon contact with amine vapors and solutions. Due to the defined pore size of the framework, the fluorescence sensing efficiency showed organic amine size dependence. The vapochromism and fluorescence quenching is attributable to electron transfer from the organic amine to the electron-deficient viologen moiety, generating colored viologen radicals. An electron-deficient metal-organic material has successfully synthesized based on the viologen ligand, which exhibit reversible photochromic behavior and selective colorimetric and luminescence sensing of organic amines. [Display omitted] • An electron-deficient viologen metal-organic material was prepared. • Compound 1 exhibit reversible photochromic behavior under UV–visible light irradiation. • Complex 1 shows colorimetric and luminescence sensing of organic amines. [ABSTRACT FROM AUTHOR]

Abstract Four new coordination polymers, namely, [Zn 2 (L) 2 (1,3-bdc)(H 2 O) 2 ] n (1) , [Cd 2 L 2 (Cl) 2 ] n ·0.5nH 2 O (2) , [Cd 2 L 2 (adip)] n ·2nH 2 O (3) , and [CdLCl] n (4) were solvothermally synthesized by reaction of Zn(NO 3) 2 ·6H 2 O, CdCl 2 ·H 2 O with an asymmetrical rigid N-heterocyclic carboxylatic acid (HL), where HL = 1-(4-carboxylphenyl)-3-(prazin-2-yl)-1H-1,2,4-triazole, 1,3-bdc = benzene- 1,3-dicarboxylic acid, H 2 adip = adipic acid, H 2 glu = glutaric acid. Compound 1 is a 1D ladder chain. Compound 2 is a (3,6)-connected network with the Point symbol of (42·6) 2 (44·62·88·10). Compound 3 displays a intriguing (3,3,4,4)-connected topological net with the Point symbol of (4·64·8)(4·72)(42·6·72·9)(42·6). Compound 4 presents a new (3,5)-connected topological net with the Point symbol of (3·4·5)(32·4·5·62·74). In addition, the thermal stabilities and photoluminescence properties of these compounds were also studied. Dramatically, compound 3 shows the high selectivity and sensitivity for Fe3+ cation via a luminescence quenching effect. Graphical abstract In this paper, we have synthesized four new Zn/Cd compounds based on HL, namely, [Zn 2 (L) 2 (1,3-bdc)(H 2 O) 2 ] n (1) , [Cd 2 L 2 (Cl) 2 ] n ·0.5nH 2 O (2) , [Cd 2 L 2 (adip)] n ·2nH 2 O (3) , [CdLCl] n (4). Meanwhile, the luminescence properties and thermal stabilities of 1 – 4 were also studied. Compound 3 shows the high selectivity and sensitivity for Fe3+ cation, via a luminescence quenching effect. fx1 Highlights • Four new coordination polymers were solvothermally synthesized. • HL ligand displays multiple coordination modes. • Compound 3 shows the high selectivity and sensitivity for Fe3+ cation. [ABSTRACT FROM AUTHOR]

Abstract Dy3+-activated Bi 4 Si 3 O 12 -Bi 4 Ge 3 O 12 pseudo-system phosphors have been synthesized by a solid state reaction method and characterized using XRD, SEM and fluorescence spectrometry. Upon 279 nm excitation, the emission of Dy3+ ions is observed at 486 nm (blue), 574 nm (yellow) and 662 nm (red), corresponding to 4F 9/2 → 6H 15/2 , 4F 9/2 → 6H 13/2 and 4F 9/2 → 6H 11/2 transitions, respectively. The different kinds of excitation for the luminescence intensity behaviors have been discussed through efficient Bi3+ → Dy3+ energy transfer. As Si4+ is substituted by Ge4+, the crystallization and the intensity of emission are improved; however, the value of correlated color temperature (CCT) is also increased. The values of CIE chromaticity coordinates and CCT endorse warm white light emission from the phosphor. The paper shows that phosphor could be a potential single-emitting-component warm white emitting for LED applications. Graphical abstract The energy transfer process from Bi3+ to Dy3+ takes place in Dy3+-activated Bi 4 Si 3 O 12 -Bi 4 Ge 3 O 12 pseudo-system phosphors and the value of CCT will increase when Si4+ is substituted by Ge4+. fx1 [ABSTRACT FROM AUTHOR]

A "V"-shaped terpyridine ligand 3,3':5′,3″-terpyridine (L) was firstly applied to construct metal-organic frameworks. Two Zn-MOFs, [Zn 2 (L) (BDC) 2 (H 2 O)] n (1) and {[Zn(L) (ISO)]·H 2 O} n (2) (H 2 BDC ​= ​terephthalic acid, H 2 ISO ​= ​isophthalic acid) had been successfully synthesized by L and auxiliary dicarboxylic ligands. Structurally, 1 features an unprecedented (3,3,8)-connected framework constructed from tridentate L units, mononuclear Zn units, binuclear [Zn 2 (CO) 2 ] units and BDC2− bridges. While 2 shows a rare (3,5)-connected architecture assembled from tridentate L units, mononuclear Zn units and ISO2− bridges. The different structures and topological diversities between 1 and 2 can be attributed to different twist angles between pyridine rings in L and distinct bridging angles from auxiliary ligands. Moreover, luminescent sensing experiments exhibit that 1 can act as a promising dual-responsive sensor for detecting TNP and Fe3+ in aqueous phase with high efficiency. The luminescence test paper was successfully developed to detect TNP for the practical applications. In addition, the emission quenching mechanisms of 1 towards TNP and Fe3+ were elucidated. Image 1 • Two Zn (Ⅱ)-organic frameworks were firstly fabricated by "V"-shaped terpyridine ligand. • 1 and 2 exhibit an unprecedented (3,3,8)-connected and a rare (3,5)-connected architectures, respectively. • 1 shows efficient luminescent dual-responsive sensing towards TNP and Fe3+ in aqueous media. • The test paper experiment provides a simple and reliable TNP sensing method in practical applications. • The sensing mechanisms towards TNP and Fe3+ were studied as well. [ABSTRACT FROM AUTHOR]

Coordination chemistry of pyridinyl-hexahydropyrimidine has not been studied to date, despite that the organic chemistry and coordination chemistry involving rigid bispyridine (bipy), pyrimidine and their derivatives have been widely reported. In this paper, the one-pot reaction of AgX (X = NO 3 − and ClO 4 − ) with three rigid-flexible bispyridine analogues, 2-(pyridin- n -yl)hexahydropyrimidine [n =4 ( L1 ), 3 ( L2 ), 2 ( L3 )], lead to the formation of seven complexes, namely, [AgL1(NO 3 )] n ·n(H 2 O) ( 1 ), [AgL1(NO 3 )] n ( 2 ), [Ag 6 (L1) 4 (NO 3 ) 6 ]·6(H 2 O) ( 3 ), [AgL1(CH 3 CN)] n ·n(ClO 4 ) ( 4 ), [Ag 2 (L2) 2 (NO 3 )(H 2 O)] n ·n(NO 3 )·n(H 2 O) ( 5 ), [Ag 3 (L2) 3 (CH 3 CN) 2 ] n 0.3n(ClO 4 ) ( 6 ), and [Ag 2 (L3) 2 (NO 3 ) 2 ] ( 7 ), which have been characterized by elemental analysis, IR, TG, PL, powder and single-crystal X-ray diffraction. Structural analyses indicate that the conformational transformations of L1-L3 cause diverse structures. In 1 and 2 , L1 presents modes I and II which connects adjacent Ag(I) into fes layers. In contrast, modes III and I in 3 and 4 join adjacent Ag(I) into hexanuclear and ladder chain structures. Complexes 5 and 6 show the same ladder chain structures with the L2 displaying the same coordination mode IV. L3 in 7 exhibits tripodal mode V to connect adjacent two Ag(I), thus forming dinuclear unit. Interestingly, adjacent dinuclear units are further joined by intermolecular hydrogen bonds to form kgd layer. Luminescent investigation reveals that 4 and 6 exhibit emissions from 443 to 581 nm. [ABSTRACT FROM AUTHOR]

In this paper, a series of MgGa 2 -x (Zn/Ge) x O 4 :0.001Mn (x ​= ​0, 0.05, 0.15, 0.3, 0.5, 1 and 1.2) phosphors were successfully synthesized using high temperature solid-state reaction. Under excitation at 377 ​nm, the sample has two emission peaks at 501 ​nm and 673 ​nm, respectively. In this material, Mn2+ and Mn4+ ions replace tetrahedral site (Mg site) and octahedral site (Ga site), respectively. The green emission at 501 ​nm belongs to the 4T 1 (G)→6A 1 (S) transition of Mn2+, and the red emission of 673 ​nm belongs to the 2E →4A 2 transition of Mn4+. Design of anti-counterfeiting application pattern. (a) Pattern under daylight (b) Pattern under 365 ​nm UV light (c) Pattern after the removal of 365 ​nm UV light (d) Pattern under 254 ​nm UV light (e) Pattern after the removal of 254 ​nm UV light. [Display omitted] • The emission color of MgGa 2 -x (Zn/Ge) x O 4 :0.001Mn were discussed. • The phosphors can emit several colors under different UV lamp by adjusting Zn2+/Ge4+ doping amount. • Potential application as anti-counterfeiting materials was estimated. [ABSTRACT FROM AUTHOR]

Y 2 Mg 3 Ge 3 O 12 : RE3+ (RE ​= ​Tb, Eu, Tm) phosphors were prepared by solid phase method. XRD and EDS show that the samples were pure phases. The ET efficiency of Y 2 Mg 3 Ge 3 O 12 : Tb3+, Eu3+ can reach up to 96.63%, and the mechanism is d-d interaction. In Y 2 Mg3Ge 3 O 12 : Tb3+, Eu3+, Tm3+, the intensity of Tb3+ decreases with the increase of Eu3+ concentrations, and the intensity of Tm3+ is basically unchanged, the intensity of Eu3+ increased first and then decreased. Meanwhile, the ET efficiency can reach up to 77.53%. Moreover, the luminescence intensity at 423 ​K can still be maintained at 87–96.58% of that at the initial temperature. The value of CCT which shows a decreasing trend with increasing Eu3+ concentrations also indicates that warm white light can be obtained by triple doping of Tb3+-Eu3+-Tm3+. The above findings show that these samples are likely to be used in warm w-LEDs. Single-component Y 1.46-y Mg 3 Ge 3 O 12 : 0.5 ​Tb3+, 0.04 ​Tm3+, yEu3+ white phosphors with excellent thermal stability were prepared by high-temperature solid-phase method.In this paper, Y 1.46-y Mg 3 Ge 3 O 12 : 0.5 ​Tb3+, 0.04 ​Tm3+, yEu3+ garnet-type phosphors with near-UV excitation were successfully synthesized. The energy transfer efficiency reached 77.53%. Y 1.46-y Mg 3 Ge 3 O 12 : 0.5 ​Tb3+, 0.04 ​Tm3+, yEu3+ samples have good thermal stability. When the samples were heated to 423 ​K, the luminescence intensity could still reach more than 87% and 96% of the luminescence intensity at the initial temperature. [Display omitted] • Y 2 Mg 3 Ge 3 O 12 : Tb3+, Eu3+, Tm3+ phosphors were synthesized by high-temperature solid-phase method. • The intensity at 423K can still reach 87% of that at 303 K, indicating a good thermal stability. • The maximum energy transfer efficiency was 93.63% and 77.53%. [ABSTRACT FROM AUTHOR]

In this paper, the synthesis of three new metal-organic frameworks of lanthanides (LnMOFs) {[Ln 2 (2,5-tdc) 3 (dmso) 2 ]·H 2 O} n (Ln=Ho (1) ; Gd (2) ; Eu (3) ; 2,5-tdc=2,5-thiophenedicarboxylate anion; dmso=dimethylsulfoxide), and their complete characterization, including single crystal X-ray diffraction, FTIR spectroscopy and thermogravimetric analysis are reported. In especial, photophysical properties of Eu(III) complex have been studied in detail via both theoretical and experimental approaches. Crystal structure of (1) reveals that each lanthanide ion is seven-coordinated by oxygen atoms in an overall distorted capped trigonal – prismatic geometry. The 2,5-tdc 2− ligands connect four Ln(III) centers, adopting ( κ 1 – κ 1 )–( κ 1 – κ 1 )– μ 4 coordination mode, generating an 8-connected uninodal 3D network. In addition, theoretical studies for Eu(III) complex were performed using the Sparkle model for lanthanide complexes. [ABSTRACT FROM AUTHOR]

This paper demonstrates the effects of Li+ co-doping on the structure, morphology, and luminescence properties of GdVO4:Er3+/Yb3+ phosphor prepared using a high-temperature solid-state chemistry method. The GdVO4:Er3+/Yb3+ powders synthesized with the Li+ co-dopant (in concentrations of 0, 5, 10, and 15 mol%) are characterized by X-ray powder diffraction, scanning electron microscopy, and photoluminescence spectroscopy. Structural analysis showed that powders co-doped with Li+ have larger crystallite sizes and slightly smaller crystal lattice parameters than powders prepared without Li+ ions. Photoluminescence down-conversion (345-nm excitation) and up-conversion (980-nm excitation) spectra show characteristic Er3+ emissions, with the most intense bands peaking at 525 nm (²H11/2→4I15/2 transition) and 552 nm (4S3/2→4I15/2). The intensity of up-conversion emission from GdVO4:Er3+/Yb3+ is enhanced (by a factor of four) by co-doping with 5 mol% of Li+ ions. The mechanisms responsible for this emission enhancement are discussed. [ABSTRACT FROM AUTHOR]

Exploring an operative approach to design materials for phosphor-converted light-emitting diode (pc-LED) remains a tough challenge, in which host structure of phosphor plays a decisive role. In this paper, we report the synthesis, structure and property analysis of Y 2 ZnGe 4 O 12 :Eu3+. The blue emission (380–500 ​nm) from the host lattice intrinsic defect and the orange-red emission (500–800 ​nm) from Eu3+ under an ultraviolent excitation was observed in the solid solution. EDX analysis and Rietveld refinement on both XRPD and NPD data indicate the existence of host lattice intrinsic defect of Y 2 ZnGe 4 O 12 ; Density Functional Theory (DFT) calculations suggest the oxygen and germanium vacancies induce the blue emission. The structural analysis implies the orange-red emission comes from the enhanced 5D 0 – 7F 4 transition of Eu3+ from an antiprism crystal-field. The exciton distribution mechanism was suggested to explain the light tuning and a mathematical description was given to demonstrate the manipulation of the blue and red lights. This work may inspire further work of new solid-state phosphor designing. A continuously adjustable white-light-emitting phosphor in wide range of correlated color temperature (CCT) was synthesized through careful control of europium doping concentration in Y 2-x Eu x ZnGe 4 O 12. Blue emission band was found originated form structural-defect-introduced non-bonding orbital, offering insight on designing new defect luminescence materials. [Display omitted] • Complete luminescence study on a novel phosphor host lattice system of Y 2 ZnGe 4 O 12 :Eu3+. • Host defect luminescence study by structural analysis and DFT calculations. • Abnormal enhanced 5D 0 – 7F 4 transition of Eu3+ from crystal field effect. • Obtainment of a series of cold to warm white lights. [ABSTRACT FROM AUTHOR]

A series of Ba 3- x Sr x ZnNb 2 O 9 : 0.3Eu3+ (x ​= ​0, 0.5, 1, 1.5, 2, 2.5, 3) orange-red phosphors were synthesized by high-temperature solid-phase reaction. In order to identify and describe the crystal structure, luminescence characteristics and thermal stability of the samples, XRD and luminescence spectroscopy tests were carried out. The refined XRD results showed that Eu3+ ions have been successfully doped into Ba 3- x Sr x ZnNb 2 O 9 matrix and occupied partly the sites of Eu3+ ions. Under UV excitation of 396 ​nm, the emission spectra of the samples are composed of two emission peaks near 593 ​nm and 612 ​nm with a slight blue shift, attributed to the increase in splitting degree of 5 d electron orbit of Eu3+ ions. At 523 ​K, the thermal stabilities of phosphors with Sr2+ ion doping concentration of 2 and 3 are 82.14% and 84.33%, respectively. With the increase of Sr2+ ion concentration, the activation energy increases from 0.198 ​eV to 0.230 ​eV, better than the other reports. In addition, the CCT (below 2000 K) and color purity (above 95%) of the samples are calculated. A WLED device can be obtained by combining the as-prepared orange red-emitting phosphor with commercial blue (BaMgAl 10 O 17 : Eu2+) and green ((Sr, Ba) 2 SiO 4 : Eu2+) phosphors. All these indicated that the self-made phosphors are promising to be used in UV/n-UV pumped WLEDs requiring low CCT. In this paper, a near-ultraviolet excited perovskite niobate Ba 3- x Sr x ZnNb 2 O 9 : 0.3Eu3+ phosphors were synthesized successfully. The study found that the replacement of Ba2+ by Sr2+ ions enhances the luminous intensity and thermal stability of the phosphor, and the replaced phosphor is more suitable for high-power WLEDs than Ba 3 ZnNb 2 O 9 : 0.3Eu3+. [Display omitted] • A serious of orange red-emitting Ba 3- x Sr x ZnNb 2 O 9 : 0.3Eu3+ phosphors were synthesized successfully. • The occupancy conditions of Eu3+ ion is discussed through the refined results of XRD. • The blue-shift of the emission peaks have been explained by the theory of crystal field splitting in the luminescent center. [ABSTRACT FROM AUTHOR]

A battery of Dy3+ single-doped and Dy3+/Eu3+ co-doped Y 2 Mg 3 Ge 3 O 12 phosphors were manufactured by high-temperature solid-phase method. The XRD patterns were tested and Rietveld refined. When the samples were excited by 352 ​nm near ultraviolet light, the energy transfer efficiency can reach 83.2%, and the energy transfer mechanism is electric dipole-electric dipole interaction. The thermal stability of Y 1.75 Mg 3 Ge 3 O 12 :0.05Dy3+, 0.2Eu3+ was tested. When the temperature reached 150 ​°C, its luminous intensity droped to 92.4% of the initial temperature (30 ​°C). By changing the concentrations of Eu3+, white light with red light can be obtained. The above results indicate that these samples are expected to become candidate materials in the domain of solid-state lighting. In this paper, a near-ultraviolet excited garnet type Y 2 Mg 3 Ge 3 O 12 : Dy3+/Eu3+ phosphors were synthesized successfully. The energy transfer efficiency reaches 83.2%. The Y 1.95-y Mg 3 Ge 3 O 12 : 0.05Dy3+, yEu3+ samples have excellent thermal stability. When the sample was heated to 150 ​°C, the luminous intensity can still reach 92.4% of the luminous intensity at the initial temperature. [Display omitted] • Y 1.95-y Mg 3 Ge 3 O 12 :0.05Dy3+, yEu3+ were synthesized by high temperature solid phase method. • For Y 1.95-y Mg 3 Ge 3 O 12 : 0.05Dy3+, yEu3+ phosphors, the energy transfer efficiency is calculated to be 83.2%. • The emission intensity can still reach 92.4% at 423K of that at room temperature. [ABSTRACT FROM AUTHOR]

In this paper, the concentration series of MgAl 2 O 4 :Nd3+ nanocrystalline powders have been synthesized by modified Pechini method. Neodymium doping concentration was varied within range of 0.05–5 ​at.%. The obtained samples have been analyzed using the various experimental methods: X-Ray diffraction, scanning electron microscopy, energy dispersive X-Ray spectroscopy, as well as steady-state and kinetics photoluminescence spectroscopy. According to XRD, all synthesized samples are monophasic without any structural impurities. The doping concentration effect on the luminescent characteristics of MgAl 2 O 4 :Nd3+ nanocrystalline particles has been studied in terms of emission intensity and lifetime. The optimal doping Nd3+ concentration was determined to be 0.1 ​at.%. Concentration quenching in MgAl 2 O 4 :Nd3+ powders occurred via energy transfer among the nearest neighbor ions. Performed studies shed the light on behavior of Nd3+ ions in nanoscale magnesium aluminum spinel. The Nd3+ doping concentration effect on the luminescent emission spectra of MgAl 2 O 4 :Nd3+ nanopowders. Image 1 • MgAl 2 O 4 :Nd3+ ​nanocrystalline powders were synthesized by modified Pechini method. • The most prominent emission line centered at 1075 nm is attributed to the transition ​4F 3/2 –4I 11/2. • Concentration quenching in Nd3+-doped MgAl 2 O 4 ​powders occurred via energy transfer among the nearest neighbor ions. • The optimal doping concentration was determined to be 0.1 at.%. • The synthesized MgAl 2 O 4 :Nd3+ ​samples can be regarded as bright phosphors for diverse applications. [ABSTRACT FROM AUTHOR]