PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
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2025
·Vol. 222
·期 15
·2500353
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IF 1.9
Xia Deng,Laijun Liu,Jungu Xu
The K 2 ZnV 2 O 7 material, as reported in our previous work, undergoes a phase transition from melilite-related structure to typical melilite structure upon Ga doping on the Zn site, with interstitial oxygen introduced and accompanied by an approximately two orders of magnitude ionic conductivity improvement (≈1.01 × 10 −1 S cm −1 at 600 °C for K 2 Zn 0.7 Ga 0.3 V 2 O 7.15 ). Herein, in order to further enhance the oxide-ion conduction by introducing more interstitial oxygen into the structure, a series of Ga and Mo codoped K 2 Zn 1- x Ga x V 2- y Mo y O 7+0.5 x +0.5 y (0 ≤ x ≤ 0.2, y = 0.1 and 0.2) materials are designed and synthesized via the traditional solid-state reaction method, with their phases and electrical properties being systematically studied. The results reveal that the Ga and Mo codoped materials retain the melilite-related structure and show a much lower conductivity, e.g., only ≈1.49 × 10 −2 S cm −1 at 600 °C for the composition of K 2 Zn 0.8 Ga 0.2 V 1.8 Mo 0.2 O 7.2 , despite its higher interstitial oxygen concentration compared to the single Ga-doped K 2 ZnV 2 O 7 (e.g., K 2 Zn 0.7 Ga 0.3 V 2 O 7.15 ). Therefore, the introduction of Mo into the structure appears to suppress the phase transition and decrease the mobility of interstitial oxygen for the K 2 ZnV 2 O 7 -based materials. These findings provide a more comprehensive perspective on the oxide-ion conduction optimization of melilite or melilite-related materials.
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高影响因子
OPTICAL MATERIALS
·
2025
·
IF 4.2
Sixia Li,Peng Zhang,Fang Lu,Zhou Sai,Weisheng Liu
Self-activated near-infrared (NIR) phosphors have garnered increasing attention in advanced light sources and biomedical applications owing to their simplified synthesis, cost-efficiency, non-toxicity, and especially the absence of extrinsic activator ions. However, developing efficient and thermally stable self-activated NIR phosphors remains a significant challenge for practical applications. Herein, a NIR phosphor Ca 0 · 95 LaMgSbO 6 (C 0.95 LMSO) (λex = 335 nm, λem = 710 nm) is synthesized employing a non-stoichiometric strategy, where interstitial oxygen (Oᵢ) defects are identified as the primary origin for the self-activated NIR luminescence through synergistic experimental and theoretical analyses. The controlled Ca 2+ deficiency promotes the generation of more Oᵢ defects, thereby enhancing the intensity of Oᵢ defect-induced near-infrared luminescence. Furthermore, the introduction of Bi 3+ sensitizers enables efficient energy transfer pathways, the optimized phosphor leading to exceptional photoluminescence quantum yield (68.1 %) and thermal stability (67.2 % intensity retention at 420 K). A fabricated NIR pc-LED based on Ca 0 · 95 LaMgSbO 6 :0.5 %Bi 3+ (C 0.95 LMSO: Bi 3+ ) phosphor exhibit promising performance in night vision and biomedical imaging applications. This study elucidates a defect-engineering paradigm grounded in oxygen interstitial defects, presenting a new research avenue for the development of high-performance self-activated NIR materials.
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Chemical Science
·
2025
·Vol. 16
·期 33
·15141-15154
·
IF 7.4
Xianyi Wei,Xiaohui Li,Aydar Rakhmatullin,Xiaoge Wang,Cheng Li,Hankun Xu,Sihao Deng,Lunhua He,Kun Lin,Qiang Li,Junliang Sun,Xianran Xing,Xiaojun Kuang
Zeolites have emerged as indispensable materials for applications ranging from catalysis and separation to adsorption and ion exchange, owing to their uniquely ordered porous architectures composed of well-defined channels and cavities. Inspired by the promising oxygen defect tolerance observed in various open structural frameworks, herein, we have developed a new zeolite-like feldspar structure, A2B2C2O8 with 4- and 8-membered rings, in the case of Sr1−xLaxGa2Ge2O8+0.5x, as a new family of interstitial oxide ion conductors due to its open structural framework for accommodating and transporting interstitial oxide ions. Average structural analysis revealed that the interstitial oxygen occupies the centers of 4-membered rings, existing in a coordination equilibrium quasi-free state that confers high mobility; however, this contrasts with the experimentally observed low mobility. Local structural analysis further revealed that the local collective distortions in GaO4 and GeO4 tetrahedra, together with the correlated disorder of interstitial oxygen coordinated with Ge, hidden within the average structure, are critical to interstitial oxygen mobility from the 4-membered ring to the 8-membered ring. Our findings demonstrate zeolite-like structures as a new family of interstitial oxide ion conductors, offering new insights into the intricate interplay between oxide ion mobility, collective distortions, and correlated disorder at the local scale.
研究领域:
材料科学
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固态化学
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离子传导
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功能材料
·
晶体化学
·
能源材料
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PubMed
高影响因子
INORGANIC CHEMISTRY
·
2025
·
IF 4.7
Wenzhuo Chen,Jian Yang,Jiazheng Hao,Feiran Shen,Lunhua He,Xia Deng,Jiasheng Lv,Jing Fang,Laijun Liu,Jungu Xu
The undoped K2ZnV2O7 material has a melilite-like structure, with the K+ ions distributed orderly on two distinguishable crystallographic sites, which is the main difference with the case in a typical A2B3O7 melilite material where the A site cations occupy only one crystallographic position. Herein, we report that substitution of Ga for Zn in K2ZnV2O7 would induce the K+ ions’ order-to-disorder transition and transform the K2ZnV2O7 from the melilite-like structure to a typical melilite phase, coupled with significantly enhanced oxide ion conductivity, e.g. ∼1.01 × 10–1 S/cm at 600 °C for the K2Zn0.7Ga0.3V2O7.15 sample, which is about 2 orders of magnitude higher than the parent material. The powder neutron diffraction data analysis results revealed two sites for the interstitial oxygen defects that are introduced by the donor-doping. The introduction of interstitial oxygen into the K layer strongly correlated with the K ions’ order-to-disorder transition, while the interstitial oxygens within the 5-fold (Zn/Ga/V)O4 tetrahedral rings are responsible for the enhanced oxide ion conductivity. These findings provided a comprehensive understanding of the melilite-like and typical melilite materials for the mechanism of the stabilization and migration of interstitial oxygen defects.
研究领域:
材料科学
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固体化学
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电化学
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晶体学
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无机化学
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高影响因子
Nature Communications
·
2024
·Vol. 15
·期 1
·1-9
·
IF 14.7
Hu Kejun,Li Qing,Song Dongsheng,Jia Yingze,Liang Zhiyao,Wang Shuai,Du Haifeng,Wen Hai-Hu,Ge Binghui
The recent discovery of superconductivity in infinite-layer nickelate films has sparked significant interest and expanded the realm of superconductors, in which the infinite-layer structure and proper chemical doping are both of the essence. Nonetheless, the reasons for the absence of superconductivity in bulk infinite-layer nickelates remain puzzling. Herein, we investigate atomic defects and electronic structures in bulk infinite-layer Nd 0.8 Sr 0.2 NiO 2 using scanning transmission electron microscopy. Our observations reveal the presence of three-dimensional (3D) block-like structural domains resulting from intersecting defect structures, disrupting the continuity within crystal grains, which could be a crucial factor in giving rise to the insulating character and inhibiting the emergence of superconductivity. Moreover, the infinite-layer structure, without complete topotactic reduction, retains interstitial oxygen atoms on the Nd atomic plane in bulk nickelates, possibly further aggravating the local distortions of NiO 2 planes and hindering the superconductivity. These findings shed light on the existence of structural and atomic defects in bulk nickelates and provide valuable insights into the influence of proper topotactic reduction and structural orders on superconductivity.
研究领域:
材料科学
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凝聚态物理
·
超导
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