JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
·
2023
·
IF 10.9
Mingxin Zhang,Cuiying Pei,Qi Wang,Yi Zhao,Changhua Li,Weizheng Cao,Shihao Zhu,Juefei Wu,Yanpeng Qi
Recently, the discovery of superconductivity with a critical temperature T c up to 80 K in Ruddlesden–Popper phases La n +1 Ni n O 3 n +1 ( n = 2) under pressure has garnered considerable attention. Up to now, the superconductivity was only observed in La 3 Ni 2 O 7 single crystal grown with the optical-image floating zone furnace under oxygen pressure. It remains to be understood the effect of chemical doping on superconducting La 3 Ni 2 O 7 as well as other Ruddlesden–Popper phases. Here, we systematically investigate the effect of external pressure and chemical doping on polycrystalline Ruddlesden–Popper phases. Our results demonstrate that the application of pressure and doping effectively tunes the transport properties of Ruddlesden–Popper phases. We find pressure-induced superconductivity up to 86 K in La 3 Ni 2 O 7 polycrystalline sample, while no signatures of superconductivity are observed in La 2 NiO 4 and La 4 Ni 3 O 10 polycrystalline samples under high pressure up to 50 GPa. Our study sheds light on the exploration of high- T c superconductivity in nickelates.
研究领域:
凝聚态物理
·
材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF SOLID STATE CHEMISTRY
·
2024
·
IF 3.2
Anli Zhang,Songbiao Cao,Jing Li,Na Lv,Pengchao Wei,Ning Zhu,Yijia Bai
A series of Ca 2+ -doped Ruddlesden-Popper phase perovskites Sr 3-x Ca x Fe 2 O 7-δ (x = 0∼0.4) were synthesized. Strong asymmetric FeO 6 octahedral distortion was confirmed at x = 0.2 owing to the anisotropic chemical pressure applied from preferable occupation of Ca 2+ ion at Sr2 site. Unusual high-charged oxidation state of iron ion with enhanced p → d charge transfer was collectively evidenced by X-ray photoelectron spectroscopy and Mössbauer spectroscopy . Combined electron emission spectroscopy further revealed a narrowing of the surface band gap accompanied by an apparent lowering of the conduction band edge at x = 0.2. These observations can be explained by a nontrivial partial charge disproportionated (CD) regime: d 5 L + d 5 L → d 5 L 1− n + d 5 L 1+ n , which reflects a significant correlation between anisotropic chemical pressure and CD ground state . The d 5 L 1− n ground state, which dominates the conduction band , is largely stabilized by enhancing the d (Fe)- p (O) hybridization along the c -axis. In addition, abrupt changes in both magnetism and dc electrical properties were also observed at x = 0.2. It is believed that the anisotropic crystal field correlated electronic state fluctuation of iron may facilitate magnetic phase competition and carrier transport. This work provides a comprehensive understanding of the crystallographic anisotropy and correlated valence electron behavior in Fe-base Ruddlesden-Popper perovskites , as well as quasi two-dimensional perovskite materials.
研究领域:
材料科学
·
凝聚态物理
·
表面科学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Zhi Yang,Jian Zhang,Bingxue Wu,Xin Zhao,Xuanlin Lu,Yicheng Zhao,Yongdan Li
The oxygen reduction reaction at the cathode is an essential process for protonic ceramic fuel cells . Composite cathode materials are commonly used towards the multiple requirements including high surface oxygen activity as well as sufficient electronic and ionic conductivities . In this study, a cobalt-free composite cathode composed of a perovskite La 0.6 Sr 0.4 FeO 3-δ phase and a Ruddlesden-Popper La 1.2 Sr 0.8 NiO 4+δ phase is synthesized with a self-assembly technology. The cathode process is mainly controlled by (I) the reduction of adsorbed oxygen atom to O − on the surface and (II) the migration of O − from the surface into the lattice. The former benefits from the high electrical conductivity of La 0.6 Sr 0.4 FeO 3-δ , and the latter is accelerated by La 1.2 Sr 0.8 NiO 4+δ attributed to its superior oxygen activity. The one-pot synthesized composite cathode shows an enhanced synergistic effect due to the uniform distribution of the two phases at the nanoscale. The cathode shows the lowest polarization resistances of 0.055 and 0.095 Ω cm 2 at 700 °C in oxygen and air, respectively. The results show that self-assembled La 0.6 Sr 0.4 FeO 3-δ -La 1.2 Sr 0.8 NiO 4+δ nanocomposite is a promising cathode material for protonic ceramic fuel cells.
研究领域:
材料科学
·
能源科学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Debo He,Wenji Ruan,Jibiao Li,Jiupai Ni,Chengsheng Ni
The large-scale integration of intermittent renewable energies into the power grid could reduce the CO 2 emission from the combustion of fossil fuel, but it requires energy storage techniques to balance the energy production and demand. The electrolysis of CO 2 that converting electricity into chemicals/fuels provides a sustainable way of energy storage and CO 2 reduction. Solid oxide electrolysis cell (SOEC) operating at around 800 °C was able to provide highly efficient transformation of CO 2 because the high temperature was able to decrease the energy demand and increase the activation of CO 2 than room temperature electrolysis. In this study, Mo-doped ferrite perovskite , La 0.55 Sr 0.45 Fe 0.85 Mo 0.15 O 3 , was studied as the cathode of an SOEC for the direct electrolysis of CO 2 at 800 °C. Cell with La 0.55 Sr 0.45 Fe 0.85 Mo 0.15 O 3 cathode showed a significantly higher current density during CO 2 electrolysis than the one with La 0.55 Sr 0.45 FeO 3 cathode. Compared with the parent La 0.55 Sr 0.45 FeO 3 cathode that will subject to a superficial decomposition into Fe 0 and SrO or SrCO 3 at an elongated cathodic bias of − 1.4 V, Mo-doping will induce the production of Ruddlesden-Popper phase ( e.g. (La,Sr) 2 (Mo,Fe)O 4 , Fe-Mo-O oxides and Fe 0 ). La 0.55 Sr 0.45 Fe 0.85 Mo 0.15 O 3 cathode was found to an unobvious current decrease at − 1.1 V, but a cell degradation was found under a high bias of − 1.4 V. During the 97 h’ aging under a cathodic bias (−1.4 V), the reduced molybdenum cation in La 0.55 Sr 0.45 Fe 0.85 Mo 0.15 O 3 was found to be less mobile than Fe 3+/2+ , La 3+ or Sr 2+ , and the perovskite with Fe-deficit region were also found to be important for the activation of CO 2 and dissociation of CO in the electrochemical process.
研究领域:
材料科学
·
电化学
·
能源存储
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Physical Chemistry Letters
·
2025
·
IF 4.6
Qilin Wei,Tongtong Kou,Tong Chang,Liang Wang,Xinxin Han,William W. Yu
Ruddlesden−Popper phases Cs2CdCl4 and Cs3Cd2Cl7 are widely used in experimental research of optoelectronics due to their excellent doping matrix properties, but their optoelectronic mechanisms have not been fully explored. This study uses first-principles calculations and experiments to analyze the differences in point defect crystal growth and optoelectronic properties caused by Sb doping of these two materials. Sb tends to replace the position of Cd in both structures. Additional doping energy levels are introduced in the Sb doping of Cs2CdCl4, and the flat band edge increases the local charge density and improves the electron-hole recombination efficiency. The photoluminescence quantum yield (PLQY) of 0.1% Sb:Cs2CdCl4 doping is as high as 79.09%. Molecular dynamics simulations show that the octahedral distortion of [SbCl6]3– in Cs2CdCl4 is highly sensitive to temperature, and the Jahn–Teller distortion causes the formation of self-trapped excitons, which is more conducive to the generation of exciton recombination luminescence. In contrast, Sb doping of Cs3Cd2Cl7 produces a lower PLQY, which can be explained by the more delocalized charge distribution at its band edges and the lower octahedral structural distortion. Sb:Cs2CdCl4 exhibits high-performance X-ray imaging capabilities. This work provides valuable insights and guidance for optimizing Sb-doped Cd-based optoelectronic materials.
研究领域:
光电材料
·
材料科学
·
凝聚态物理
·
计算材料学
·
X射线成像技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ADVANCED MATERIALS
·
2019
·Vol. 31
·期 42
·1903889
·
IF 25.809
Guangbao Wu,Xing Li,Jiyu Zhou,Jianqi Zhang,Xuning Zhang,Xuanye Leng,Peijun Wang,Ming Chen,Dongyang Zhang,Kui Zhao,Shengzhong (Frank) Liu,Huiqiong Zhou,Yuan Zhang
Layered Ruddlesden–Popper (RP) phase (2D) halide perovskites have attracted tremendous attention due to the wide tunability on their optoelectronic properties and excellent robustness in photovoltaic devices. However, charge extraction/transport and ultimate power conversion efficiency (PCE) in 2D perovskite solar cells (PSCs) are still limited by the non-eliminable quantum well effect. Here, a slow post-annealing (SPA) process is proposed for BA 2 MA 3 Pb 4 I 13 ( n = 4) 2D PSCs by which a champion PCE of 17.26% is achieved with simultaneously enhanced open-circuit voltage, short-circuit current, and fill factor. Investigation with optical spectroscopy coupled with structural analyses indicates that enhanced crystal orientation and favorable alignment on the multiple perovskite phases (from the 2D phase near bottom to quasi-3D phase near top regions) is obtained with SPA treatment, which promotes carrier transport/extraction and suppresses Shockley–Read–Hall charge recombination in the solar cell. As far as it is known, the reported PCE is so far the highest efficiency in RP phase 2D PSCs based on butylamine (BA) spacers ( n = 4). The SPA-processed devices exhibit a satisfactory stability with <4.5% degradation after 2000 h under N 2 environment without encapsulation. The demonstrated process strategy offers a promising route to push forward the performance in 2D PSCs toward realistic photovoltaic applications.
研究领域:
光伏技术
·
材料科学
·
钙钛矿太阳能电池
·
薄膜光电子学
·
晶体工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）