查找使用阿拉丁产品的科研文献

High thermal stability and quantum efficiency of (Sr,Ba)2Ga2SiO7: Eu2+ phosphors for full-spectrum WLEDs

Daiyuan Liu,Ru Zhao,Chao Wang,Zhichao Liu,Jian Zhang,Yuan Wang,Xue Yu,Jianbei Qiu,Xuhui Xu,Yichun Liu

High-quality phosphors with color tunability are urgently needed for the full-spectrum white light-emitting diodes (WLEDs) with healthy and comfortable lighting like the solar spectrum. Here, a Sr 2 Ga 2 SiO 7 : Eu 2+ phosphor with tunable luminescence color is reported, achieving a luminescence tuning from maize-yellow to yellow by changing the Eu 2+ ion concentration. Importantly, the quantum efficiency of BaSrGa 2 SiO 7 : 1.0 % Eu 2+ is as high as 85.7 % compared with 49.1 % of Sr 2 Ga 2 SiO 7 : 5.0%Eu 2+ , and the emission intensity of BaSrGa 2 SiO 7 : 1.0 % Eu 2+ retains 92 % of the room temperature (RT) emission intensity at 473 K by Ba 2+ substitution. Furthermore, the increase of Ba 2+ ion concentration also makes the phosphor achieve tunability from yellow to green. The as-prepared full-spectrum WLEDs exhibits a continuity spectrum like solar spectrum with an extremely high color rendering index of 93.5 and low correlated color temperature of 4562 K. This work provides new insights into the exploration of new phosphors for high-performance full-spectrum WLEDs devices.

Preparation of K2SbPO6-Loaded Porous Geopolymer Particles for Efficient Sr(II) Removal: Adsorption Performance and Mechanism

Chufeng Cheng,Wei Fang,Gaoshang Ouyang,Jingsong Wang

To achieve efficient separation of Sr2+under complex ionic-strength conditions, porous geopolymer particles (PGs) were used as a support to construct a K2SbPO6-loaded porous geopolymer composite, denoted as K2SbPO6@PGs, via in situ loading of one-dimensional K2SbPO6by a high-temperature solid-state route. Its adsorption performance and mechanism were systematically compared with those of pristine PGs. Structural characterization (SEM/EDS, XRD, FTIR, XPS, and BET) confirmed that the K2SbPO6crystalline phase was uniformly anchored onto the PGs framework while preserving interconnected mesoporous channels. K2SbPO6@PGs exhibited excellent Sr2+removal over a wide pH range (3–12), with a removal efficiency of approximately 92% at pH 3, which was significantly higher than that of PGs (approximately 5%). The isotherm data were better fitted by the Sips model (R2= 0.982), and the maximum adsorption capacity reached 189.35 mg·g−1(theoretical qm = 201.14 mg·g−1). Kinetic fitting showed that PGs followed the pseudo-first-order model, whereas K2SbPO6@PGs were better described by the pseudo-second-order model, indicating that chemical adsorption dominated the process through K+/Sr2+exchange and surface complexation. Coexisting-ion experiments demonstrated strong resistance to monovalent ions, whereas Ca2+and Mg2+caused more pronounced competitive effects. The results indicate that PGs mainly provide interconnected mass-transfer pathways and granular structural support, whereas K2SbPO6provides selective exchange sites with high affinity for Sr2+. The synergy between these two components endows the composite with good pH adaptability and enhanced adsorption performance and suggests its potential for subsequent continuous-flow separation studies.

Synergistic Regulation of Thermal Expansion and Conduction in Epoxy Composites via (Ca,Sr)SnF6 Ceramic Filler

Xin Jin,Feiyu Qin,Ruixin Li,Xin Yang,Yuanbin Qin,Jun Sun,Xiangdong Ding,Lei Hu

Low thermal expansion and high thermal conductivity are essential for advanced integrated circuit packaging materials. In this study, an isotropic negative thermal expansion fluoride, Ca 0.85 Sr 0.15 SnF 6 (CSSF), exhibiting a linear coefficient of thermal expansion, α l of −7.3 × 10 −6 /°C, is synthesized via a hydrothermal method. TEM results capture the diverse lattice distortion in CSSF, including attractive Moiré fringe, dislocations, and obvious lattice strain. Subsequently, CSSF is introduced into epoxy resin (EP) to design the unconventional CSSF/EP composites. Compared with the pure epoxy, the composite with 60 wt.% CSSF filler exhibits a significant reduction in α l , from 69.5 × 10 −6 /°C (glassy region) and 172.0 × 10 −6 /°C (rubbery region), down to 35.8 × 10 −6 /°C and 87.4 × 10 −6 /°C, respectively. Meanwhile, the thermal conductivity increases from 0.19 to 0.48 W·m −1 ·°C −1 . Moreover, a higher Shore hardness (93.3 HD) is achieved for the CSSF60/Epoxy composite. Furthermore, the composite demonstrates desirable dielectric properties, with a dielectric constant of 9.48 and a dielectric loss of 0.166 at 1 MHz. In particular, fracture surface analysis reveals that CSSF filler achieves strong interfacial adhesion with the epoxy matrix without surface treatment, which can be attributed to its isotropic nature. This unconventional strategy of incorporating NTE fluorides into EP presents a viable approach for advanced electronic packaging applications.

AIn3Si4P9 (A = Ca, Sr): quaternary phosphides with double-helix structures exhibiting high laser-induced damage thresholds

Ming-Shu Zhang,Bin-Wen Liu,Xiao-Ming Jiang,Guo-Cong Guo

Two quaternary phosphides AIn3Si4P9 (A = Ca, 1; Sr, 2) belonging to the non-centrosymmetric space group P41212 are discovered and synthesized through the solid-state method for the first time. They present extraordinary double-helix frameworks composed of corner-shared tetrahedral [InP4] and [SiP4] units. Although compounds 1 and 2 have undesirable band gaps (1.25 and 1.15 eV), their extremely low thermal expansion coefficients (∼10−6) result in high laser-induced damage thresholds approximately seven times that of benchmark AgGaS2 under a 2050 nm laser. Moreover, both compounds show weak second-harmonic generation intensities primarily caused by Kleinman forbidden nonlinear optical coefficients. Theoretical calculations further reveal that the electron transitions mainly originated from the tetrahedral [InP4] and [SiP4] units.

Novel high-entropy microwave dielectric ceramics Sr(La0.2Nd0.2Sm0.2Eu0.2Gd0.2)AlO4 with excellent temperature stability and mechanical properties

Feng Li Lin,Bing Liu,Cheng Chao Hu,Kai Xin Song

Novel high-entropy Sr(La 0.2 Nd 0.2 Sm 0.2 Eu 0.2 Gd 0.2 )AlO 4 ceramics with a layered perovskite structure have been prepared via the standard solid-state reaction method. The design of high-entropy improves the bond valence and subsequently optimizes the large negative temperature coefficient of resonant frequency ( τ f = −32 ppm/°C) of the simple SrLaAlO 4 ceramics. Excellent temperature stability ( τ f = −6 ppm/°C) together with a relative permittivity ( ε r ) of 18.6 and a quality factor ( Qf = 14,509 GHz) are obtained in Sr(La 0.2 Nd 0.2 Sm 0.2 Eu 0.2 Gd 0.2 )AlO 4 ceramics sintered at 1475 °C. It indicates that the present ceramics have great application prospects in passive microwave components such as resonators and filters. Meanwhile, significant improvements in compressive strength and strain are achieved, which are 1040 MPa and 15.7% for Sr(La 0.2 Nd 0.2 Sm 0.2 Eu 0.2 Gd 0.2 )AlO 4 compared to 583 MPa and 12% in SrLaAlO 4 . The enhanced mechanical properties originate from the dislocation strengthening mechanism as the intertwining of interlayer lattices is revealed from the high-resolution transmission electronic micrographs.

Facile Synthesis of MOF-Derived Hierarchical Flower-Like Sr-Doped Co3O4 Structure for Effective TEA Sensing

Heming Sun,Xiaonian Tang

Electrocatalytic degradation of perfluorooctanoic acid by LaNixY1-xO3 (Y = Fe, Cu, Co, Sr) gas dispersion electrode

Yongyang Chen,Dan Guo,Xiaochun Dong,Yahui Li,Yixuan Huang,Hao Chen,Shanping Li

Perfluorooctanoic acid (PFOA), as a refractory organic pollutant, seriously harms the environment and damages human health. Here, the electrocatalytic method was selected to degrade PFOA. In this work, perovskite catalysts doped with different elements, and corresponding gas diffusion electrodes (GDE) were prepared by the gel-sol method and citric acid complexation method. The crystal structure, microscopic morphology, and electrochemical properties of the LaNi x Y 1-x O 3 (Y = Fe, Cu, Co, Sr) perovskite catalyst electrode were analyzed by XRD, TEM, and CV. Moreover, the electrocatalytic performances of the as-prepared electrodes were assessed by the degradation of PFOA, and the Sr-doped GDE exhibited the highest degradation rate of PFOA. The optimum degradation conditions, such as the current density, pH, and initial concentration were also investigated. It was observed that when the current density was 20 mA/cm 2 , pH was 5, and initial concentration was 0.25 mmol/L, the Sr-doped GDE had the best degradation and defluorination efficiency of PFOA reached 90.0 % and 75.1 %, respectively. High performance liquid chromatography-mass spectrometry (HPLC-MS) was used to analyze the intermediate products of PFOA degradation and obtain the degradation pathway. With the combined action of OH and O 2 , PFOA was degraded by stepwise removal of CF 2 groups, which were ultimately degraded into F − and CO 2 .

Tunable luminescence of Bi3+/Eu3+-doped SiO2–Al2O3-MCO3 (M = Ca, Sr, Ba) glasses for WLED

Falin Zhang,Xiaoying Liang,Rongfei Wei,Hai Guo,Fangfang Hu

In this work, a group of Bi 3+ /Eu 3+ -doped SiO 2 –Al 2 O 3 -MCO 3 (M = Ca, Sr, Ba) glasses were fabricated through melt-quenching method. Their structure and photoluminescence characters were studied via X-ray diffraction (XRD), UV–Vis transmission spectra (TRS), excitation spectra, emission spectra and decay lifetimes. The XRD results show that no nano-crystal phase forms in glass matrix with different doping concentrations of Bi 3+ and Eu 3+ ions. Through regulating optical alkalinity value, the intensity of Bi 3+ ions increases and the peak position shifts to red wavelength. The Bi 3+ /Eu 3+ co-doped glasses show a blue-white-yellow-red luminescence by changing concentration of Eu 3+ ions. Energy transfer efficiency from Bi 3+ to Eu 3+ can reach as high as 10.54%. At 423 K, the emission intensity of 55SiO 2 –10Al 2 O 3 –35BaO-0.25Bi 2 O 3 (GBE0.5) is 31.1% of that at 308 K. Meanwhile, the activation energy of the glass matrix is 0.251 eV. All results suggest that these Bi 3+ /Eu 3+ co-doped glass samples possess potential application in LED field.

The immobilization of Sr(ll) and Co(ll) via magnetic easy-separation organophosphonate-hydroxyapatite hybrid nanoparticles

Keren Lu,Zhiren Zhao,Jin Cui,Cuiyun Bai,Hongling Zhang,Xuetao Zhao,Fengyun Wang,Mingzhu Xia,Yanru Zhang

The magnetic Hexamethylene diamine tetramethylene phosphonic acid (HDTMP)-hydroxyapatite nanoparticles (HD-MHAP) were firstly prepared and applied for the immobilization of radioactive Sr 2+ (Strontium ion) and Co 2+ (Cobalt ion). The molar ratio of organic phosphine in HDTMP to total phosphorus was 10% (10HD-MHAP) and can also be easily separated from aqueous solution. At the equilibrium concentration of Sr 2+ and Co 2+ (200 mg/L), the adsorption capacity of MHAP and 10HD-MHAP on Co 2+ was 28.4 mg/g and 172.3 mg/g, respectively and for Sr 2+ , the adsorption capacity was 54.9 mg/g and 320.7 mg/g. Additionally, the desorption percentage of Sr 2+ (%) and Co 2+ (%) was very low, which was 0.66 and 1.61, respectively. This is significant because the irreversible adsorption of HDTMP/Fe 3 O 4 /HAP composite for Sr 2+ and Co 2+ ensures the captured radionuclides will not be released back into the aquatic systems. Moreover, the affinity between HDTMP and HAP and the coordination of HDTMP and Sr 2+ or Co 2+ was probed by Multiwfn wavefunction analysis. The results indicated that the formation of a ternary surface complex of MHAP-HDTMP-M (Sr 2+ or Co 2+ ) was the key to the excellent immobilization performance of HD-MHAP composite for Sr 2+ or Co 2+ .

Solution-processed Sr-doped NiOx as hole transport layer for efficient and stable perovskite solar cells

Jiankai Zhang,Wujian Mao,Xian Hou,Jiaji Duan,Jianping Zhou,Sumei Huang,Wei Ou-Yang,Xuehua Zhang,Zhuo Sun,Xiaohong Chen

Nickel oxide (NiO x ) hole transport layer (HTL)-based planar perovskite solar cells (PSCs) have attracted much attention due to high power conversion efficiency (PCE) and simple processing. In this work, smooth and compact Sr-doped NiO x films with different Sr doping concentration were successfully prepared through a simple low temperature sol-gel method. The 1 at.% Sr-doped NiO x HTL-based PSCs exhibited the best performance with PCE of 20.07%, which is greatly higher than PCE of reference NiO x based PSCs (15.73%). Furthermore, the unencapsulated PSCs based on Sr:NiO x HTL still retains over 60% of the original PCE value aging for 100 days under ambient air, showing better stability. The superior performance of Sr-doped NiO x based PSCs is attributed to better electrical conductivity, crystallinity of perovskite film and energy level matching with perovskite layer, which can greatly improve hole transport and extraction abilities and reduce carrier recombination, resulting in high PCE and better stability.

Enabling efficient visible light photocatalytic water splitting over SrTaO2N by incorporating Sr in its B site

Xiaoqin Sun,Fangfang Wu,Gang Liu,Xiaoxiang Xu

The perovskite oxynitride SrTaO2N is a promising compound for solar energy conversion because it has strong visible light absorption at wavelengths as long as 650 nm. However, its photocatalytic activity is generally very poor, primarily because of the high defect concentration induced during its synthetic procedures as well as photocatalytic self-decomposition events. In this work, we introduce Sr into the B site of SrTaO2N to form a complex perovskite oxynitride, Sr3(Sr1/3Ta2/3)3O9−xNy (i.e. Sr4Ta2O9−xNy). The new compound has a much lower defect concentration compared to SrTaO2N and much higher stability against photocatalytic self-decomposition. More importantly, Sr4Ta2O9−xNy demonstrates significantly improved photocatalytic activity for water oxidation and reduction reactions under visible light irradiation (λ ≥ 400 nm) than SrTaO2N, approaching an apparent quantum efficiency as high as 3.4% at 420 ± 20 nm.

Energy transfer and luminescence properties of Sr[1−3(x+y)/2]Al2B2O7:xEu3+, yBi3+ phosphor

Renping Cao,Tao Liang,Wensheng Li,Chunyan Cao,Yufeng Wen,Qianglin Hu

Sr [1−3( x + y )/2] Al 2 B 2 O 7 : x Eu 3+ , y Bi 3+ ( x   =   0–5   mol% and y   =   0–5   mol%) phosphors are synthesized by a solid-state reaction method in air, and their crystal structure, fluorescence lifetime, and luminescence properties are investigated. The optimal composition is determined to be (Sr 0.94 Eu 0.03 Bi 0.01 )Al 2 B 2 O 7 . The PLE band peaks within the range 200–550   nm are due to O 2−   →   Eu 3+ charge transfer band, 7 F 0   →   5 H 3 , 5 D 4 , 5 L 7 , 5 L 6 , 5 D 3 , 5 D 2 , and 5 D 1 transitions, respectively. The strongest PL band peak under excitation 394   nm light is at ∼615   nm owing to 5 D 0   →   7 F 2 transition of Eu 3+ ion. The PL intensity of Eu 3+ , Bi 3+ co-doped SrAl 2 B 2 O 7 phosphor is 1.3   times that of Eu 3+ doped SrAl 2 B 2 O 7 phosphor due to the energy transfer between Eu 3+ and Bi 3+ ions, which is explained by the energy level diagrams of Bi 3+ and Eu 3+ ions. The CIE chromaticity coordinates of Sr 0.955 Al 2 B 2 O 7 :0.03Eu 3+ and Sr 0.94 Al 2 B 2 O 7 :0.03Eu 3+ , 0.01Bi 3+ phosphors under excitation 394   nm light are ( x   =   0.6292, y   =   0.3702) and ( x   =   0.6284, y   =   0.3711), respectively. These phosphors will be used as reddish orange emitting phosphor candidate for white LED with ∼394   nm near ultraviolet LED chip.