CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Wei Wang,Hang Yang,Meiqian Fu,Xinyang Zhang,Mengyu Guan,Yi Wei,Chun Che Lin,Guogang Li
Thermal quenching is still a pivotal challenge for phosphor materials in white light emitting diodes lighting applications. Herein, we propose an effective strategy to design a near zero-thermal-quenching green emission in zero-thermal-expanding Zn 4 B 6 O 13 host based on unique 3D isotropic cage structure. The integrated emission intensity of Zn 4 B 6 O 13 :Mn 2+ could maintain 103% of initial intensity at 150 °C and 98% at 250 °C under blue light excitation. During the low-frequency vibrations, the unchanged bonds and angles induce the zero thermal expansion, and the unaffected lattice and coordination environment contribute the nearly unchanged emission intensity during the heating process. In addition, an efficient self-reduction of activators in the studied system is ascribed to vacancy and interstitial oxygen defects act as donors to provide electrons. This work initiates a novel strategy to construct thermally-stable and self-reductive phosphors for multiple optical applications.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
INORGANIC CHEMISTRY
·
2022
·
IF 5.436
Chen Li,Ke Liu,Dequan Jiang,Cheng Jin,Tianyao Pei,Ting Wen,Binbin Yue,Yonggang Wang
Negative thermal expansion (NTE) and zero thermal expansion (ZTE) properties are of great significance for the long-life stable operation of precision equipment. However, there are still existing challenges in finding new materials that exhibit NTE or ZTE over a wide temperature range. Here, we report negative, zero, and positive thermal expansion in NiAs-type, defective Cr1−δTe, containing three compounds: hexagonal CrTe, monoclinic Cr3Te4, and trigonal Cr5Te8. CrTe shows the NTE behavior from 280 to 340 K with the volume coefficient of thermal expansion αV = −27.6 × 10–6 K–1. Cr3Te4 shows the ZTE behavior over a wide temperature range of 180–320 K (αV = 0.16 × 10–6 K–1). And Cr5Te8 holds the PTE behavior over the whole temperature range (αV = 38.5 × 10–6 K–1). All of the samples show obvious anisotropic thermal expansion on heating. Combined with the magnetic measurements, it can be confirmed that the NTE and ZTE properties in ferromagnetic Cr1−δTe originate from the magnetovolume effect (MVE). Such NiAs-type, defective compounds with similar compositions but different structures provide a new perspective for tuning the NTE properties of materials and searching for new materials with ZTE over a wide temperature range.
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
PubMed
高影响因子
Inorganic Chemistry Frontiers
·
2022
·Vol. 9
·期 8
·1692-1700
·
IF 7.779
Decai Huang,Xianguo He,Jingrong Zhang,Jie Hu,Sisi Liang,Dejian Chen,Kunyuan Xu,Haomiao Zhu
In recent years, near-infrared phosphor-converted light emitting diodes (NIR pc-LEDs) have been emerging as a promising compact and efficient NIR light source for a variety of applications such as sensing, bioimaging and food analysis. However, the development of broadband NIR phosphors with both high emission efficiency and excellent photoluminescence (PL) thermal stability is still facing a great challenge. Herein, a blue light excitable AlP3O9:Cr3+ phosphor with a broadband NIR emission covering 650–1000 nm is presented. In particular, in situ variable-temperature XRD measurements demonstrate that the AlP3O9:Cr3+ phosphor shows a near zero thermal expansion in the temperature range of 300–423 K, which is beneficial for achieving good PL thermal stability. The experiment shows that ∼91% of the PL intensity is retained at 423 K compared to that at room temperature, verifying our hypothesis. An efficient NIR pc-LED is fabricated by using the AlP3O9:Cr3+ phosphor and commercial blue diode chips, generating a NIR radiant flux of 29.5 mW at 60 mA drive current. Finally, the NIR pc-LED was successfully used as the light source for identifying spoiled eggs based on the NIR spectroscopic technique. This work provides a strategy to achieve high performance NIR phosphor systems.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
CHEMISTRY OF MATERIALS
·
2022
·
IF 10.508
Youquan Liu,Xingxing Jiang,Maxim S. Molokeev,Xingyu Zhang,Zheshuai Lin
With the capability to keep the size invariant along all dimensions over a certain temperature range, isotropic zero thermal expansion (ZTE) materials have been attracting wide interest in many scientific and engineering fields. Herein, based on the “cage-restricting” model for the ZTE materials with β-sodalite-like structures, we design and synthesize two new isotropic ZTE materials, Zn3GaB6O12As (ZGBA) and Zn4P6N12S (ZPNS), from the molecular engineering strategies of enhancing the cage-restricting force and of increasing the rigidity of β-sodalite cages, respectively. ZGBA and ZPNS exhibit isotropic ZTE behaviors in the temperature range from 20 to 300 K, with the coefficients of thermal expansion 1.18(17)/MK and 1.37(17)/MK, respectively, both of which are lowered by ∼30–20% in comparison with their template compound Zn4B6O12S (ZBS). The mechanisms of improved isotropic ZTE in ZGBA and ZPNS are unraveled by lattice dynamic analysis and temperature-dependent crystal structure evolution. This study paves new avenues to enhance the ZTE behavior in the materials with cage-like structures and has great implication on the exploration of isotropic ZTE materials.
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2022
·
IF 6.371
Chang Zhou,Yongxiao Zhou,Saiyue Liu,Lianyu Zhang,Peiyu Song,Qiang Zhang,Biyuan Ma,Gaohui Wu
Negative thermal expansion particles can compensate metal matrix composites to achieve near-zero thermal expansion materials. However, there are huge thermal residual mismatch stresses in the particles due to the thermal expansion mismatch between matrix and reinforcement. The use of hybrid reinforcement is required to solve the stress concentration problem. In this study, the hybrid Al matrix composites reinforced with ZrW 2 O 8 and SiC reinforcements (SiCp, SiCnw) were fabricated by the pressure infiltration process. The effect of SiC content on microstructure, phase composition, thermal expansion and mechanical properties were examined by a combination of XRD , SEM, thermal dilatometer and bending tests. The results showed that the high-pressure phase (γ-ZrW2O8) content of hybrid metal matrix composites decreased with increasing SiC fraction. Among them, the composites containing 61.7 vol%ZrW 2 O 8 and 3.3vol%SiCnw achieved the best performance with a bending strength of 100–150 MPa and a near-zero thermal expansion (2.0–3.0 ×10 –6 K −1 ) in a wide range of − 50–120 °C, which was attributed to the synergetic hybrid effects of SiCnw and ZrW 2 O 8 . This work opens up a new frontier for the design and preparation of lightweight zero-thermal expansion materials.
研究领域:
材料科学
·
力学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2020
·
IF 4.495
Keqiang Zhang,Kai Wei,Jiaxin Chen,Bo Liang,Daining Fang,Rujie He
Ceramics and their structures with tunable thermal expansion are deemed necessary to develop. In this study, multi-ceramic structures with tunable thermal expansion, including negative thermal expansion (NTE), zero thermal expansion (ZTE), and positive thermal expansion (PTE), were developed for the first time. Firstly, multi-ceramic triangle structures with tunable thermal expansion were designed based on ZrO 2 and Al 2 O 3 ceramics. Then, multi-ceramic triangle structures were fabricated by using the stereolithography additive manufacturing technology. Functionally gradient ceramic (FGC) layers were applied for releasing the thermal mismatch stress among the structure. Finally, the thermal expansion behavior of the multi-ceramic triangle structures were characterized and analyzed by using a homemade thermal expansion testing system. The proposed design, fabrication and characterization methods of multi-ceramic structures with tunable thermal expansion are believed to promote the engineering application.
研究领域:
材料科学
·
制造工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）