Journal of Materials Chemistry C
·
2022
·Vol. 11
·期 3
·1082-1094
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IF 8.067
Xueshuang Jiang,Yubo Long,Kaijin Chen,Qiaoxi Yu,Long Jiang,Zhenguo Chi,Siwei Liu,Jiarui Xu,Yi Zhang
Two new bioderived diamines with two cis-fused cyclopentane ring structures, bis(4-aminophenyl) (octahydropentalene-2,5-diyl)dicarbamate (OAC) and 4,4′-((octahydropentalene-2,5-diyl)bis(oxy))dianiline (OOD), were designed and synthesized from natural citric acid for the first time. Two series of new bio-based polyimides ((PI(B/F/HAC) and PI(B/F/HOD)) were developed by the polymerization of OAC and OOD with three commercial dianhydrides, respectively. Due to the introduction of the two cis-fused cyclopentane ring structures with optically asymmetric active carbon atoms, the as-prepared polyimides exhibit light color or even colorless and transparent properties, as well as interesting optical activities. The transmittance at 400 nm and total optical transmittance (380–800 nm) for PI(HAC) are 83.5% and 86.6%, and those for PI(HOD) are 84.3% and 88.5%, respectively. PI(BAC) containing carbamate moieties in the polymer backbone shows excellent dimensional stability and mechanical properties, with a coefficient of thermal expansion (CTE) value below 18 ppm k−1 (close to that of Cu), a tensile strength of 115.8 MPa and a modulus of 2.9 GPa. The relationship between the structure and properties of polymers was also investigated through molecular simulation and Gaussian calculations. In addition, we have studied the biodegradable behaviors of these bio-based polyimides. After 49 days of degradation by porcine pancreatic lipase, the number average molecular weight and weight average molecular weight of PI(FAC) changed by approximately 75% and 90%, respectively, which proved to be a potential solution to the environmental problems caused by polyimide. This work provides new ideas for the development of new biomass functional monomers, chiral polymers, and biodegradable polyimides, which have strong academic exploration value.
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CHEMISTRY-A EUROPEAN JOURNAL
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2022
·Vol. 28
·期 53
·e202201588
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IF 5.02
Ru-Ling Tang,Xin Lian,Xiao-Hui Li,Lei Huai,Wenlong Liu,Sheng-Ping Guo
Graphical Two new mixed-alkali metal tantalum fluorides CsATaF 7 (A=K, Na) were synthesized by hydrothermal reactions based on the parent compounds A 2 MF 7 (A=monovalent cations and M-d 0 transition-metal cation). Interesting structure transformation for β-K 2 TaF 7 , CsKTaF 7 , and CsNaTaF 7 are induced via alkali metal cation regulations. Among them, CsNaTaF 7 crystallizes in polar structure and own moderate SHG effect. Inorganic metal halides play important roles in wide range of areas including fluorescence, X-ray detection, and nonlinear-optics. Herein, two new mixed alkali metal tantalum fluorides, CsKTaF 7 and CsNaTaF 7 , have been obtained based on the strategy of cations regulation in A 2 MF 7 (A represents monovalent cations and M is d 0 transition-metal cation) system by a conventional hydrothermal route. CsKTaF 7 crystallizes in the centric Pnma space group, while CsNaTaF 7 crystallizes in the polar Cmc 2 1 space group and exhibits moderate and phase-matchable NLO activity. Both halides possess large optical band gaps above 5.0 eV. The crystal structure evolution, optical properties, and detailed theory calculations of these two halides were elucidated in this work.
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DALTON TRANSACTIONS
·
2022
·Vol. 51
·期 37
·14214-14220
·
IF 4.569
Song Qing,Xi Zhang,Tao Yang,Lingxiang Chu,Yayun Zhou,Jing Wan,Zhengliang Wang,Huaijun Tang,Qiang Zhou
In this work, a series of Cr3+-doped A2NaYF6 (denoted as ANYF:Cr; A = K, Rb, and Cs) fluoroyttrate double-perovskites with broad blue excitation and near-infrared (NIR) emission bands were prepared using a high-temperature solid-state reaction method. The physicochemical and spectroscopic properties of the as-prepared products, including crystal structure, bandgap, morphology, luminescence behaviour and optical performance, were studied in detail. The results show that the Cr3+ activators undergo a decreasing crystal field in ANYF in the direction from K to Cs, yielding a red shift of the emission peak position from 758 to 786 nm, whilst the full-width-at-half-maximum (FWHM) expands from 98 to 104 nm. By virtue of the broadband NIR emission, clear structural images of the tangerine section, mini LED flashlight and circuit board were obtained by merging the optimal RNYF:Cr phosphor on a blue InGaN chip, implying its potential use in light-emitting diodes for non-destructive testing.
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Nano Energy
·
2022
·
IF 19.069
Zhihai Wu,Yichen Zhang,Bintao Du,Keyang Yang,Jun Wu,Tianyi Dai,Chengkun Dong,Jun Xia,Anlang Wu,Zhenfu Zhao
Perovskite nanocrystals (PNCs) are promising to replace the traditional phosphor color conversion layers in backlit displays due to their excellent optical properties , which can enhance the color gamut and saturation of displays. However, poor stability and low luminescence efficiency hinder the development of perovskite-based devices. Here, inspired by the Yunnan cicada wing, a low-cost, easy-to-fabricate, and large-area (> 78 cm 2 ) all-dielectric metasurface based on the Purcell effect is developed to tune and improve the light extraction efficiency of PNCs. All-dielectric metasurfaces composed of weakly disordered TiO 2 /PS spheres are embedded in the PNCs/PVDF ( Poly (vinylidene fluoride)) films prepared by in-situ fabrication strategy, resulting in 3.19-fold photoluminescence (PL) maximum enhancement of these composite films . The stability of PNCs is also markedly improved after PVDF encapsulation. As an application demo, these all-dielectric metasurface-modulated perovskite composite films are applied in LCD backlit, with the color gamut of 157% of commercial LCD and 107% of NTSC, showing tremendous potential in high-end lighting and display. Furthermore, combined with the scalability of large-area fabrication, cost-effective weakly disordered metasurfaces are a potential method to bridge the gap between high-efficient laboratory demonstrations and commercialization in the field of display.
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JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2023
·
IF 5.7
Wenhao Li,Zexuan Sui,Chunli Fan,Ci Wang,Yao Zhu,Jing Ren,Jianzhong Zhang
Nano-glasses are next-generation scintillators combining favorably the merits of both scintillator crystals and glasses. Here, a new nano-glass scintillator is prepared embedding CsGd 2 F 7 :Ce 3+ nanocrystals (NCs). The microscopic morphology, particle size, and distribution of the NCs are studied by high resolution transmission electron microscopy . Significantly enhanced radioluminescence efficiency is obtained in the nano-glasses. The largest integrable intensity of X-ray excited luminescence is 316% of the standard Bi 4 Ge 3 O 12 (BGO) crystal. A well-resolved full-energy peak with an energy resolution of 17.4% is registered for the 662 keV gamma rays, and the light yield is determined to be 827 ± 8 ph/MeV. The nano-glass scintillators exhibit good radiation hardness and thermal stability. As a proof of concept, an X-ray imaging system of a good resolution is built on the nano-glass scintillators.
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JOURNAL OF LUMINESCENCE
·
2023
·
IF 3.6
Yi Qin,Lingxiang Chu,Tao Yang,Jing Wan,Qiang Zhou,Yanqing Ye,Huaijun Tang,Zhengliang Wang
In this study, an efficient polyfluoride red-emitting phosphor, Cs 3 RbGe 2 F 12 :Mn 4+ (denoted as CRGF:Mn), has been synthesized using a simple co-precipitation method. The crystal and electronic structures, spectroscopic properties, and photoluminescence thermal stability of CRGF:Mn have been systematically characterized. The results show that Mn 4+ ions experience a strong crystal field and present a series of intense red emission peaks under blue light excitation. Moreover, CRGF:Mn exhibits a high color purity (95.1 %), high internal quantum efficiency (82.4 %), and enhanced photoluminescence thermal stability at 150 °C, with an intensity of 113 % relative to room temperature . A warm white light-emitting diode exhibiting a low correlated color temperature (3572 K), high color rendering index (90.7), and suitable luminous efficiency (132.6 lm/W) was prepared using CRGF:Mn as a red component, demonstrating viable application in solid-state lighting.
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Molecular Catalysis
·
2023
·
IF 4.6
Yanzhao Gao,Xianglei Meng,Shiqi Huang,Hui Wu,Liantao Jiang,Yu Zhou,Yuting Song,Yanyan Diao
Gamma alumina is widely utilized for preparing the supported noble metal catalysts for the hydrogenation reaction. It is an effective strategy to improve the catalytic performance of catalysts via modifying gamma alumina with alkaline earth metal to regulate its surface acidity and electronic properties. Herein, Pd catalysts supported by Al 2 O 3 and Mg-modified Al 2 O 3 are synthesized via the wet impregnation method, and the effects of MgO doping on the structure, composition, and surface acidity of Pd/γ-Al 2 O 3 catalysts are investigated via X-ray diffraction patterns (XRD), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Temperature programmed desorption (TPD). The results show that Pd/MgO-Al 2 O 3 –2 (γ-Al 2 O 3 modified with 2 wt% Mg) has more metallic state palladium and weak acid sites and exhibits the best catalytic performance for the hydrogenation of perfluoro-4-methyl-2-pentene (D1). Density functional theory (DFT) calculations on Pd/Al 2 O 3 and Pd/MgO-Al 2 O 3 –2 catalysts are also performed to further explore the mechanism of D1 hydrogenation. The studies for Gibbs free energy of the potential reaction steps and intermediates reveal a complex process to generate the target product C 6 F 12 H 2 , and the rate-determining-step is the addition of the first hydrogen on the second carbon of perfluoro-4-methyl-2-pentene molecule.
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OPTICAL MATERIALS
·
2023
·
IF 3.9
Qun Jing,Menglin Zhu,Lu Li,Xu Ji,Haiming Duan,Henglei Chen,Ming-Hsien Lee
In recent years, phosphates have become a research hotspot to explore new ultraviolet (UV) nonlinear optical (NLO) materials. Herein, two NLO materials MZnPO 4 (M = Rb, Cs) are synthesized by cation substitution in alkali-zinc orthophosphates. Although they crystallize in different space groups P 2 1 and Imm 2, respectively, they both have a honeycomb-like topological structure consisting of corner-shared PO 4 and ZnO 4 tetrahedra and separated by "M" cations. Two compounds exhibit mild powder second harmonic generation (SHG) responses (1.2 and 0.5 × KDP for RbZnPO 4 and CsZnPO 4 , respectively) with type I phase matching behaviors and short absorption edges (226 nm for RbZnPO 4 and 231 nm for CsZnPO 4 ). Furthermore, their thermal properties , infrared (IR) spectra and theoretical calculations are also mentioned in the paper. The synthesis and structure-property relationship described in the system will enable discovery of new NLO materials.
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MACROMOLECULAR BIOSCIENCE
·
2023
·
IF 4.6
Runhai Chen,Yu Xia,Zhifang Ma,Yue Ke,Qiang Shi,Fazly I. Ataullakhanov,Mikhail Panteleev
Excessive amounts of reactive oxygen species (ROS) cause various biological damages and are involved in many diseases, such as cancer, inflammatory and thrombotic complications, and neurodegenerative diseases. Thus, ROS-responsive polymers with inherent ROS scavenging activity and biodegradability are extremely needed for the efficient treatment of ROS-related diseases. Here, this work fabricates the amphiphilic diblock copolymer PEG-b-PBC via ring-opening polymerization (ROP) of phenylboronic acid ester conjugated cyclic carbonate monomer. The copolymer easily forms micelles (BCM) and scavenges ROS rapidly. BCM not only releases the delivered drug but degrades to produce the small molecules p-hydroxybenzyl alcohol (HBA) with anti-inflammatory capability in the presence of H 2 O 2 . BCM can reduce the oxidative stress of human umbilical vein endothelial cells (HUVEC) and the levels of inflammatory factors secreted by macrophages, showing antioxidative and anti-inflammatory activity. Finally, BCM exerts a significant capability to reduce the complications of inflammation and thrombosis in vivo. The biodegradable aliphatic poly(carbonate)s have the potential to be used for drug delivery systems (DDS) for diseases induced by reactive oxygen species.
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Advanced Optical Materials
·
2023
·
IF 9
Sisi Liang,Liping Song,Wendong Nie,Zihao Wang,Dejian Chen,Fulin Lin,Haomiao Zhu
Synthesis of a Mn 4+ -activated fluoride red-emitting phosphor combining high efficiency, excellent thermal stability, and outstanding moisture resistance still remains a challenge. Herein, this work synthesizes a red-emitting phosphor Cs 2 NbF 6 : Mn 4+ (CNF: Mn 4+ ) based on the cation-exchange method. Interestingly, as a result of the redox reaction between Mn 3+ (Mn 2+ ) and Nb 5+ ions during the exchange reaction, the real Mn 4+ concentration is remarkably increased, while Nb 5+ ions are reduced to Nb 4+ . The obtained optimum CNF: Mn 4+ phosphor shows high internal and external photoluminescence (PL) quantum yield (QY) of 92% and 58%, respectively. Moreover, the CNF: Mn 4+ exhibits excellent thermal stability ( I @150 = 105%) and moisture resistance. A white light-emitting diode (LED) packaged by combining blue diode chips, Y 3 Al 5 O 12 :Ce 3+ yellow phosphor, and CNF: Mn 4+ red phosphor demonstrates a low correlated color temperature (CCT) of 3872 K, high color rendering index (CRI) of Ra = 88, and a luminous efficacy of 105 lm W −1 . The high-performance of the white LED suggests the great potential of the CNF: Mn 4+ narrowband red phosphor in display and lighting fields.
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ACS Applied Materials & Interfaces
·
2021
·
IF 9.229
Hongkun Liu,Bingbing Zhang,Ling Li,Ying Wang
Deep-UV (DUV) nonlinear optical (NLO) materials are of vital importance to demanding DUV laser applications; however, those with a large NLO coefficient, wide band gap, and sufficient phase-matching ability are rare. In this work, by combining π-conjugated B3O6 groups and distort AlO3F tetrahedra, we successfully designed and synthesized two fluoroaluminoborates, RbAlB3O6F (RABF) and Cs0.5Rb0.5AlB3O6F (CRABF). In addition, the solid solution CsxRb1–xAlB3O6F (0.2 < x < 0.8) polycrystalline samples were obtained by the standard solid-state reaction. It was shown that all these compounds are NLO-active and possess short UV cutoff edges (<200 nm). Interestingly, although they have the same fundamental structural units, their crystal structures and second harmonic generation (SHG) responses are significantly different owing to the cation effect. Theoretical calculations reveal that both B3O6 and AlO3F groups contribute to the SHG responses. Remarkably, it also indicates that RABF exhibits a large birefringence (Δn = 0.0946 at 1064 nm), which is capable of realizing deep-UV phase matching down to 174 nm. The exploration of fluoroaluminoborates provides a new perspective for searching excellent deep-UV NLO materials.
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MICROPOROUS AND MESOPOROUS MATERIALS
·
2020
·
IF 4.551
Tianjiao Wang,Hongyan Yao,Ningning Song,Yanchao Yang,Kaixiang Shi,Shaowei Guan
In recent years, linear polyimides of intrinsic microporosity have been widely used in the field of gas adsorption and separation because of their high BET surface area and microporous structures. Most of the microporous structures come from the twisted main-chain structures in the linear polyimides of intrinsic microporosity. Therefore, most linear polyimides (PI) without twisted structure have no porosity. Herein, to construct the linear polyimide with microporous structure, a sequence of microporous polyimides (PIs-CL) were constructed from the flexible linear polyimide precursors through the thermal crosslinking reaction. The polyimide precursors without twisted structure were synthesized from a well-designed diamine TFVBPA with cross-linkable ethynyl groups and several commercial dianhydrides (ODPA, BPDA, PMDA and 6FDA) by polycondensation to research the influence of the main-chain structure on the porous characters. The introduction of crosslinked structures gives the linear crosslinked polyimides (PIs-CL) with porous structures. The PIs-CL show obviously improved porosity (0.52–1.71 nm) and higher BET surface area (337–618 m 2 g −1 ) than those of the uncrosslinked polyimides (PIs). Moreover, PIs-CL have favorable CO 2 adsorption (5.7–9.3 wt%) as well as good CO 2 /N 2 selectivity (34.4–58.5) at 273 K, which are better than other polyimides materials. The introduction of crosslinked structures is an effective way to improve microporous porosity and gas sorption performance.
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