JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
·
IF 6.2
Jinrong Gao,He Bai,Xiao Ling,Yunjiang Yang,Xinru Liu,Zhipeng Fan,Jinrong Bao,Wenxian Li,Ying Liu,Xiaowei Zhu
A rare earth organic complex, SiO 2 @ATPA-Si-RE (RE = Eu, Tb), exhibiting a core-shell structure, was synthesized using the ligand (HOOC) 2 C 6 H 3 NHCONH(CH 2 ) 3 Si(OCH 2 CH 3 ) 3 (ATPA-Si) to connect the silica microspheres core and coordinate with rare earth ions. The pH value of the reaction was adjusted to produce organic complex shells with thicknesses of 2.0 nm and 5.0 nm, while the SiO 2 core measured a diameter of 125 nm. Luminescence spectra indicated that the emission intensity of the SiO 2 @ATPA-Si-RE (RE = Eu, Tb) core-shell structure was stronger than that of the ATPA-Si-RE organic complex due to a perfect match between the triplet energy level of SiO 2 @ATPA-Si and the excited energy level of rare earth ions (Eu 3+ , Tb 3+ ). Remarkably, the core-shell structure with a 2.0 nm shell thickness possessed a greater emission intensity compared to the 5.0 nm shell thickness. Moreover, these findings unveiled the tunability of luminescence color, ranging from green or red to white, by adjusting the doping ratio of Eu 3+ and Tb 3+ ions and the coating thickness of complexes. Particularly, a warm white light emission, characterized by CIE coordinates (0.389, 0.347), a color rendering index value of 86.7, and a low correlated color temperature value of 3550 K, was achieved using the organic complex with a 2.0 nm thickness coated on SiO 2 microspheres with a doping ratio of Eu 3+ at 0.7 mmol and Tb 3+ at 0.3 mmol. Conversely, the complexes with a 5.0 nm coating thickness and Tb 3+ doping ratio of 0.3 mmol yielded a cold white light emission. These findings demonstrate the potential applications in next-generation lighting industry and display systems.
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高影响因子
JOURNAL OF RARE EARTHS
·
2026
·
IF 9.6
Biao Xu,Zihao Xu,Chunyu Li,Jian Peng,Xingyu Li,Wubin Dai
Phosphor with thermally stable and highly efficient photoluminescence (PL) is a premise/challenge for use in high-quality phosphor-converted light-emitting diodes (pc-LEDs). Herein, via a facile solid-phase sintering method in air, a negative thermal quenching (TQ) blue emitting SrGa 2 B 2 O 7 (SGB): Bi is reported, mainly associating with the underlying collaborative effect of negative volumetric thermal expansion of rigid host, heterovalent substitution (Bi 3+ → Sr 2+ )-induced V Sr /V O vacancies, and generating self-reduction ions (Bi 2+ ). For charge balance under the condition of temperature rising, both opposite process of self-oxidation (Bi 2+ to Bi 3+ ) and charge release from trap levels can compensate blue-PL loss. This phosphor is comparable to Eu 2+ /Ce 3+ -activated blue-emitting phosphors, and even boasts superior quantum efficiency (QE) and thermal stability. Via artificially codoping Na + for charge compensation, the QE of the SGB:Bi/Na can be further significantly enhanced. Color-tunable PL is achieved via cascade-connected energy transfer (ET) from Bi 3+ to Tb 3+ (green)/Eu 3+ (red) in SGB: Bi/Na/Tb/Eu that possesses high QE/stability than the case of blue/green/red tricolor phosphor blends adopted in warm white LEDs (wLEDs). Finally, the SGB: Bi/Na and SGB: Bi/Tb/Eu/Na are respectively, encapsulated with distinct encapsulants via either traditional or remote “capping” packaging strategy to form blue LEDs and wLEDs, showcasing splendid electroluminescence behaviors and luciferous application prospects.
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高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Jingfang Tong,Weijie Lin,Ruixin Guo,Zhongzheng Deng,Haitao Zhou,Shu Guo,Xiaojun Kuang
Strong magnetic anisotropy in low-dimensional magnets leads to a significant rotating magnetocaloric effect, presenting new opportunities for the exploration of more efficient and streamlined refrigeration systems. In this study, we have successfully synthesized a series of centimeter-scale rare-earth-containing fluorocarbonates, K 4 RE 2 (CO 3 ) 3 F 4 ( RE = Ce, Pr, Nd, Sm, Eu, Tb, and Dy) through a supercritical hydrothermal method, featuring unique RE 2 O 12 F 4 magnetic dimers. The above materials' fundamental magnetism has been systematically investigated, and no long-range magnetic transitions were captured above 1.8 K. Based on the low-temperature specific heat results, the long-range magnetic ordering was found around 0.84 K and 0.97 K for K 4 Tb 2 (CO 3 ) 3 F 4 and K 4 Dy 2 (CO 3 ) 3 F 4 , respectively. Furthermore, the anisotropic magnetism of K 4 Tb 2 (CO 3 ) 3 F 4 and K 4 Dy 2 (CO 3 ) 3 F 4 reveals significant magneto-crystalline anisotropy, with the magnetic field ( B ) aligned along the RE 2 O 12 F 4 magnetic dimer, which acts as the easy magnetic axis. The maximum rotating field entropy change, − Δ S R max for K 4 Tb 2 (CO 3 ) 3 F 4 reaches approximately 9 J kg -1 K -1 around 17 K, while for K 4 Dy 2 (CO 3 ) 3 F 4 , it is approximately 5.5 J kg -1 K -1 near 11 K, both under a 7 T field applied along the c -axis. These findings highlight the potential of these compounds for magnetic refrigeration applications through a rotating crystallographic direction.
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高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2015
·
IF 5.33
Xiaolei Zhang,Jingjing Deng,Yumeng Xue,Guoyue Shi,Tianshu Zhou
In this study, we demonstrate a colorimetric and fluorescent dual-mode method for alkaline phosphatase activity (APA) sensing in freshwater lake with stimuli-responsive gold nanoparticles@terbium-guanosine monophosphate (Au-NPs@GMP-Tb) core–shell nanoparticles. Initially, the core–shell nanoparticles were fabricated based on Au-NPs decorated with a fluorescent GMP-Tb shell. Upon being excited at 290 nm, the as-formed Au-NPs@GMP-Tb core–shell nanoparticles emit green fluorescence, and the decorated GMP-Tb shell causes the aggregation of Au-NPs. However, the addition of ALP destroys GMP-Tb shell, resulting in the release of Au-NPs from the shell into the solvent. As a consequence, the aggregated Au-NPs solubilizes with the changes in the UV–vis spectrum of the dispersion, and in the meantime, the fluorescence of GMP-Tb shell turns off, which constitutes a new mechanism for colorimetric and fluorescent dual-mode sensing of APA. With the method developed here, we could monitor the dynamic change of APA during an algal bloom of a freshwater lake, both by the naked eye and further confirmed by fluorometric determination. This study not only offers a new method for on-site visible detection of APA but also provides a strategy for dual-mode sensing mechanisms by the rational design of the excellent optical properties of Au-NPs and the adaptive inclusion properties of the luminescent infinite coordination polymers.
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PubMed
高影响因子
Materials Chemistry Frontiers
·
2022
·Vol. 7
·期 1
·168-182
·
IF 8.683
Peiran Huang,Zuhui Wen,Yue Yu,Jingyi Xiao,Zhanhua Wei,Tianshuai Lyu
X-Ray or 254 nm UV-light charged storage phosphors have various promising applications such as in anti-counterfeiting and information storage. However, developing such storage phosphors with high charge carrier storage capacity remains challenging. In this work, photoluminescence spectroscopy, thermoluminescence (TL), and vacuum-referred binding energy (VRBE) diagram were combined to study the trapping and liberation processes of charge carriers in Bi3+ and/or Ln3+ (Ln = Tb, Pr, or Dy) doped LiLuGeO4. Unintended defects act as good electron trapping centers, while Bi3+, Tb3+, and Pr3+ act as hole-capturing and recombination centers. Dy3+ does not act as an electron trapping center but as a luminescence center by energy transfer from Bi3+ → Dy3+. The ratios of the integrated TL intensities between 303 K and 650 K for LiLuGeO4:0.005Bi3+, LiLuGeO4:0.005Bi3+,0.005Tb3+, or LiLuGeO4:0.005Bi3+,0.005Dy3+ after X-ray charging to that of the state-of-the-art BaFBr(I):Eu2+ is about 1.24, 0.59, and 0.90, respectively. More than 10 h or 40 h afterglow was measurable in both LiLuGeO4:0.005Bi3+ and LiLuGeO4:0.005Bi3+,0.005Tb3+ after X-ray or 254 nm UV-light charging. The stored charge carriers stored can be efficiently excited to produce optically stimulated luminescence with a wide range 365 nm UV-light to 850 nm infrared laser beam. Proof-of-concept colour-tailorable afterglow, X-ray irradiation time or sample mass-dependent dosimetry, and optically-stimulated luminescence with a wide range of 365 nm UV-light to 850 nm infrared laser stimulation will be demonstrated for anti-counterfeiting, information storage, and display applications in the developed Bi3+ and/or Ln3+-doped LiLuGeO4. This work not only reports Bi3+ and/or Ln3+ doped LiLuGeO4 storage phosphors with excellent charge carrier storage capacity but also deepens our understanding of the afterglow and storage phosphors and luminescence mechanisms, which can guide us to explore new afterglow and storage phosphors for multimode applications.
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高影响因子
OPTICAL MATERIALS
·
2024
·
IF 3.8
Mengran Ouyang,Huimin Du,Jiahao Wu,Shanshan Hu,Jun Yang
KSrGd(PO 4 ) 2 :Ln 3+ (Ln = Ce, Sm, Eu, Tb, Dy, Dy/Eu, Yb/Ho, Yb/Er, Yb/Tm) phosphors were synthesized by high temperature solid state method. Doping the KSrGd(PO 4 ) 2 matrix with 5%Dy 3+ ions resulted in white light emission under 345 nm excitation. The calculated color temperature (CCT) of this white light is 5523 K, indicating as positive white light. It was found that the luminous intensity of the obtained KSrGd(PO 4 ) 2 :5%Dy 3+ at 200 °C was 76.80 % of that at room temperature, showing good thermal stability as well as possibility of application in white LED. Under the excitation at 392 nm, the fluorescence quantum yield of KSrGd(PO 4 ) 2 :10%Eu 3+ is 79.92 %. Energy transfer between Dy 3+ and Eu 3+ is observed in KSrGd(PO 4 ) 2 :Dy 3+ /Eu 3+ samples, with identified mechanism as the quadrupole-quadrupole interaction. Tunable luminescence ranging from white to yellow then to orange-red is achieved by adjusting the doping concentration of Eu 3+ in KSrGd(PO 4 ) 2 :5%Dy 3+ , x%Eu 3+ . Under the excitation of 980 nm near-infrared light, the prepared KSrGd(PO 4 ) 2 :Yb 3+ /Ho 3+ , KSrGd(PO 4 ) 2 :Yb 3+ /Er 3+ and KSrGd(PO 4 ) 2 :Yb 3+ /Tm 3+ samples showed up-conversion emissions of red, yellow and blue, respectively, with two-photon processes. In KSrGd(PO 4 ) 2 matrix, multi-color and multi-security marks were successfully prepared by utilizing up/down conversion luminescence characteristics, which obtained good anti-counterfeiting effect and improved anti-counterfeiting security. Therefore, the obtained KSrGd(PO 4 ) 2 : Ln 3+ phosphors exhibit promising application prospects in the fields of WLED and multiple anti-counterfeiting.
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高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
·
2019
·
IF 2.29
Zhan-Ping Qiao,Meng-Yao Su,Yuan-Lin Dang,Qi-Chao Yang
The phase diagrams of the Mg(NO 3 ) 2 –Ln(NO 3 ) 3 (Ln = Nd, Sm, Eu, Tb)–HNO 3 –H 2 O systems in the (∼20%) HNO 3 regions at T = 298.15 K were determined by using an isothermal solution saturation method. The Schreinemaker’s wet residues method was used to determine the compositions of solid-phases. Both Mg(NO 3 ) 2 –Nd(NO 3 ) 3 –HNO 3 –H 2 O and Mg(NO 3 ) 2 –Sm(NO 3 ) 3 –HNO 3 –H 2 O systems are complicated with three equilibrium solid phases Mg(NO 3 ) 2 ·6H 2 O, Mg 3 Ln 2 (NO 3 ) 12 ·24H 2 O and Ln(NO 3 ) 3 ·6H 2 O (Ln = Nd, Sm). But the systems Mg(NO 3 ) 2 –Eu(NO 3 ) 3 –HNO 3 –H 2 O and Mg(NO 3 ) 2 –Tb(NO 3 ) 3 Tb–HNO 3 –H 2 O are simple eutonic type. The two new solid-phase compounds Mg 3 Nd 2 (NO 3 ) 12 ·24H 2 O and Mg 3 Sm 2 (NO 3 ) 12 ·24H 2 O are congruently soluble in an average medium of ∼20 mass % HNO 3 , and they were identified and characterized by the methods of powder X-ray diffraction, X–ray diffraction single crystal structure analysis, and thermogravimetric/differential thermogravimetric. The XRD diffraction patterns for the two new solid-phase compounds are identical due to their isomorphic structure. They belong to hexagonal systems, with space group R 3 . For Mg 3 Nd 2 (NO 3 ) 12 ·24H 2 O, a = b = (1.0993 ± 0.0005) nm, c = (1.7211 ± 0.0007) nm, V = (1.8012 ± 0.0013) nm 3 , D c = (4.2532 ± 0.0024) g·cm −3 , Z = 3; for Mg 3 Sm 2 (NO 3 ) 12 ·24H 2 O, ( a = b = 1.1198 ± 0.0004) nm, c = (1.7257 ± 0.0006) nm, V = (1.8742 ± 0.0011) nm 3 , D c = (4.1201 ± 0.0012) g cm −3 , Z = 3. The standard molar enthalpies of solution of the compounds Mg 3 Nd 2 (NO 3 ) 12 ·24H 2 O and Mg 3 Sm 2 (NO 3 ) 12 ·24H 2 O in water (aq) were measured to be (101.26 ± 0.77) kJ mol −1 and (80.27 ± 0.81) kJ mol −1 , and their standard molar enthalpies of formation were calculated to be – (12214.13 ± 2.5) kJ mol −1 and – (12183.6 ± 2.5) kJ mol −1 , respectively.
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高影响因子
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