JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2024
·
IF 3.5
Le Fu,Wenjun Yu,Bohan Wang,Ying Deng
Extensive efforts have been devoted to investigate the distribution of dopants in ceramics. However, one critical question remained barely explored, which is the redistribution of dopants between amorphous and crystalline phases during fast sintering of ceramics. Here we address this gap by observing the redistribution of five selected dopants (Y, Ce, Yb, Hf, and Ta) in ZrO 2 –SiO 2 nanoceramics during sintering. We designed two groups of experiments: In group one, dual-phase amorphous particles were sintered with multicomponent crystalline ones. The former particles were ZrO 2 –SiO 2 glass, whereas the latter ones consisted of ZrO 2 solid-solution nanocrystallites (SSNCs) embedded in an oxide glass containing Zr, Si, Y, Ce, Hf, Yb, and Ta. In group two, dual-phase crystalline particles were sintered with multicomponent amorphous ones. The former particles were composed of ZrO 2 nanocrystallites (NCs) embedded in an amorphous SiO 2 matrix, whereas the latter ones were oxide glass containing Zr, Si, Y , Ce, Hf, Yb, and Ta. Redistribution of the dopants from the glass to ZrO 2 NCs occurred in the two groups, that is, the five dopants migrated from the glass matrix into the ZrO 2 NCs, forming ZrO 2 SSNCs. The redistribution of the dopants not only increased the configuration entropy of the ZrO 2 NCs but also benefited the network structure integrity of SiO 2 glass. The dopant redistribution process was driven by the minimization of the studied material's free energy. The reported results are important for understanding the redistribution behaviors of dopants and are expected to provide new insights to design new ceramics via the multielement co-doping strategy.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Jianhua Zhu,Qian Xiao,Ting Zhang,Yefeng Yin,Yang Liu
The effects of acceptor dopant (typical Mn 2+ ) and donor dopant (typical V 5+ ) on the reliability of Li 2 ZnTi 3 O 8 based low temperature co-fired ceramics (LTCC, in short) have been investigated. Large difference occurs among different types of dopants. V 5+ doping decreases the breakdown voltage of the multilayer capacitors which were manufactured by low temperature sintered Li 2 ZnTi 3 O 8 ceramics, however, Mn 2+ doping increases the breakdown voltage and lowers down the leakage current significantly. This may very likely due to the fact that donor induces the generation of weak bound electrons while acceptor capture the weak bound electrons. The results suggest that Mn 2+ is a very effective additive for improving the reliability of low temperature sintered Li 2 ZnTi 3 O 8 ceramics.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2017
·
IF 6.395
Junsheng Luo,Chunyang Jia,Zhongquan Wan,Fei Han,Bowen Zhao,Ruilin Wang
Perovskite solar cells (PSCs) emerging as the most promising next-generation photovoltaic devices have been received great attention. In the PSC device, admittedly, Spiro-OMeTAD is the most widely used hole-transporting material (HTM). However, the pristine Spiro-OMeTAD suffers from low hole mobility and conductivity, which requires chemical dopants (Li-TFSI and tBP) to increase conductivity thereby improving power conversion efficiency (PCE). Discouragingly, hygroscopic Li-TFSI can gravely degrade the perovskite film and diminish the stability of PSC. Meanwhile, tBP also gives rise to the degradation of perovskite film by forming a [PbI 2 ·tBP] coordinated complex or iodopyridinate complex. In this study, F4-TCNQ is introduced into Spiro-OMeTAD as an alternative dopant to replace the commonly used Li-TFSI and tBP. By optimizing the doping concentration of F4-TCNQ, the PSC based on 1.5 mol% F4-TCNQ doped Spiro-OMeTAD exhibits the best PCE as high as 12.93%, which is comparable to that of 14.32% for reference device with Li-TFSI and tBP doped Spiro-OMeTAD. Moreover, the PSC based on F4-TCNQ doped Spiro-OMeTAD shows lower hysteresis and better stability. This work not only offers a promising dopant for Spiro-OMeTAD, but also provides a viable approach to address the challenges of hysteresis and instability.
研究领域:
材料科学
·
能源技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ELECTRONIC MATERIALS
·
2018
·Vol. 48
·期 1
·374-385
·
IF 1.566
Tong Huanzhe,Wang Nengli,Zou Yuqi,Zhang Zhaoquan,Fan Wugang,Shou Jinxiang,Zhang Xiyan
Yttrium aluminum garnet (Y 3 Al 5 O 12 , YAG) ceramics with a relative density of about 99.5% were fabricated by solid-state reaction and pressureless sintering using commercial α-Al 2 O 3 and Y 2 O 3 powders as raw materials in air. The effect of different sintering additives, e.g. tetraethyl orthosilicate (TEOS), MgO and TEOS + MgO, on the relative density and mechanical properties of the YAG ceramic samples were investigated. When the dopant content of TEOS exceeded 0.5 wt.%, a sudden grain growth appeared, as well as a residual second phase located in triangle grain boundary. MgO was more effective as a sintering additive than silica in promoting the densification of the YAG ceramics. The relative density of the ceramics gradually decreased with the increase of MgO doping content and fixed TEOS content. The mechanical properties of the YAG ceramics fabricated by pressureless sintering in air at 1600–1710°C were tested. The fracture surface morphology of the MgO-doped ceramic samples was mainly transgranular, whereas the TEOS-doped samples were mainly intergranular.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
Advanced Optical Materials
·
2017
·Vol. 5
·期 20
·1700448
·
IF 6.875
Kai Zhang,Chong-Geng Ma,Jun-Ying Zhang,Bo-Mei Liu,Yang Zhou,Shao-Qiang Guo,Jia-Yue Xu,Jing-Shan Hou,Yong-Zheng Fang,Li-Rong Zheng,Hong-Tao Sun
Relaxing chemical pressure in phosphors with large-size-mismatched dopants, aiming at attaining high-efficiency luminescence and a higher dopant concentration, remains a challenging subject of continuous research effort. Originally seen as undesirable and detrimental to the performance of luminescent systems, this study demonstrates that the formation of a tiny amount of oxygen vacancies favors chemical pressure relaxation (CPR), resulting in topotactic transformation of poorly luminescent parent phases to highly luminescent cousins, as exemplified by a model system of Bi 3+ -doped Lu 2 O 3 . The integration of experimental observations with theoretical calculations reveals that the emergence of oxygen vacancies adjacent to Bi 3+ can expand its size of coordination geometry, thus releasing the chemical pressure and significantly influencing the emission characteristics. Importantly, it is illustrated that the concept of oxygen-vacancy-mediated CPR is sufficiently general to allow the optimization of luminescence from other classes of foreign-ion-doped phosphors plagued by size mismatch. It is suggested that this concept can be applied to an array of optical materials in various forms, and also provides unique opportunities for tuning other properties of functional materials that are sensitive to local coordination environments of dopants.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
Catalysis Science & Technology
·
2022
·Vol. 12
·期 11
·3670-3684
·
IF 6.177
Chunwang Lv,Mingjiang Hu,Tianhao Yuan,Liqiang Yan,Hongwei Chen
The objective of this work was to investigate and contrast the mechanism of different B-site dopants for catalytic activity and sulfur resistance under equivalent conditions. LaCo1−xMxO3 (M = Fe, Cr, Cu) perovskite-type catalysts were synthesized by a sol–gel method, and the optimized samples were tested for toluene oxidation before and after sulfur aging. The properties of the catalysts were investigated in detail by XRD, FT-IR, N2 adsorption–desorption, H2-TPR, XPS and in situ DRIFTS to elucidate the inner mechanisms of the catalytic reaction and poisoning processes. The results indicated that introducing specific metal cations with a suitable ratio into the B-site of perovskite could improve the catalytic activity and weaken the negative effect of SO2 poisoning. The reasons for the improvement of catalytic activity on different doped catalysts are similar and mainly lie in the change of reduction property, oxidation state of the B-site, and content of oxygen vacancies. However, the mechanism of sulfur resistance caused by different dopants is not identical. The introduction of different metal cations will cause certain differences in some factors such as reducibility, lattice stability, sulfur adsorption and sulfate content, thus leading to the differentiation of sulfur tolerance for doped perovskite catalysts. In this study, the optimization effect of Fe dopant is better than that of Cr and Cu dopants, illustrating that the high stability of the perovskite lattice and the insensitivity to sulfur species are the key factors for its outstanding sulfur resistance. The results provide insights into guiding the practical composition and life cycle optimization of perovskite-type catalysts in the industrial application of removing sulfur-containing VOCs.
研究领域:
化学工程
·
材料科学
✓ 已验证
DOI
高影响因子
INORGANIC CHEMISTRY
·
2025
·
IF 4.7
Yiming Zhang,Zhipeng Li,Baihua Qu,Xing Shen,Le Tong,Jin Wang,Jingqin Cui,Xin Li,Qingshui Xie,Jingfeng Wang
Sodium metal, with its high theoretical capacity, low redox potential, and cost-effectiveness, presents a promising anode candidate for next-generation high-energy-density batteries. However, the development of Na metal anodes is significantly challenged by issues such as uncontrolled dendrite growth, uncontrolled volume expansion, and associated safety concerns. Designing and developing advanced materials to enhance the conductivity of sodium metal anodes and promote uniform sodium ion deposition are of urgent importance. Herein, a MXene-based hybrid material was developed by integrating MOF-derived Zn, Co, N, and C dopants with Ti3C2Tx MXene to serve as a hosting substrate for the Na metal anode. The MXene provided a conductive framework, while the MOF-derived dopants introduced sodiophilic sites, promoting uniform Na deposition and mitigating volume expansion. The optimized material demonstrated an average Coulombic efficiency of 99.99% over 3000 cycles and stable cycling for over 5000 h in symmetrical cells and maintained over 80% capacity retention at 3 C after 500 cycles in full-cell tests, highlighting its potential as a robust Na metal anode material.
研究领域:
材料科学
·
电化学
·
能源存储
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Advanced Physics Research
·
2022
·Vol. 2
·期 4
·2200071
·
IF 0
Weifan Niu,Ruidan Zhang,Zhibin Wang,Feng Huang,Daqin Chen
Perovskite nanocrystals (NCs) with intentionally introduced Mn 2+ /Yb 3+ activators enable tunable emissions covering UV-orange-NIR spectral range. However, the exact microscopic energy transfer mechanisms in this system remain unknown. Herein, Mn/Yb codoped CsPbCl 3 perovskite NCs with triple emissions originated from exciton recombination of host, 3d–3d transition of Mn 2+ and 4f–4f transition of Yb 3+ are prepared. Femtosecond resolution transient absorption spectra performed on the pristine CsPbCl 3 , Mn-doped, Yb-doped and Mn/Yb codoped samples clarify efficient and simultaneous energy transfer (ET) from excitons to Mn 2+ and Yb 3+ dopants. It is testified the sensitizations of dopants mainly result from the trapped hole, taking 285 ps for Mn 2+ and 17 ps for Yb 3+ respectively, which make less trapped hole recombine with de-localized carriers. Importantly, energy transfer processes from host to Mn 2+ and Yb 3+ activators emerge as competition, and the ET probability of exciton-to-Mn 2+ is higher than that of exciton-to-Yb 3+ . Finally, control experiments further prove that tunable Mn 2+ orange emission and Yb 3+ NIR emission are achievable via elaborate adjustment of the dopant concentrations.
研究领域:
材料科学
·
物理化学
✓ 已验证
DOI
Journal of Materials Chemistry C
·
2016
·Vol. 4
·期 8
·1645-1650
·
IF 5.066
Jian Lin,Le Wang,Qian Zhang,Fei Bu,Tao Wu,Xianhui Bu,Pingyun Feng
Chemically co-doping a micron-sized semiconductor single crystal while simultaneously segregating different dopant types uniformly on a nanoscale is synthetically challenging, but often essential for preventing unwanted dopant-related interference that may hamper optic and magnetic applications. Here by starting from a unique molecular crystal composed of well-defined discrete supertetrahedral chalcogenide nanoclusters (NCs), we successfully realized highly effective nanosegregation of dual dopants (Cu and Mn) in Cd–In–S semiconductor crystals. Our method takes advantage of the intrinsic single vacancy at the core of NC that permits the trapping of only one dopant ion. Such single-ion trapping effectively precludes two dopant ions from residing in the same NC, allowing us to target single-crystal white-light emitter by eliminating possible interference between dopants. This new method for controlling the distribution of multiple dopants on a nanoscale provides a promising route to modify and tune optical and magnetic properties of large-sized semiconductor single crystals for use in integrated multifunctional devices.
研究领域:
材料科学
·
光学
·
化学合成
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2023
·Vol. 11
·期 11
·3751-3758
·
IF 6.4
Jingyu Li,Xueting Wang,Changshuai Dong,Sihui Deng,Junli Hu,Jun Liu,Yichun Liu
Organoboron polymers containing boron–nitrogen coordination bonds are a new class of n-type thermoelectric polymers. Their n-doping with a traditional hydride donor dopant suffers from low thermoelectric performance and unsatisfactory stability. In this manuscript, we report the n-doping of an organoboron polymer, PBN-19, with an N-heterocyclic carbene (NHC) based dopant, 1,3-dimethylimidazolium-2-carboxylate (DMImC). The DMImC doped PBN-19 film exhibits an electrical conductivity of 1.55 S cm−1 and a power factor of 5.62 μW m−1 K−2, and maintains 80.0% of its initial electrical conductivity after 1 day storage at room temperature under a nitrogen atmosphere. Detailed examinations indicate that DMImC decomposed into NHC radicals upon thermal activation, which then reacted with the CO, CC and CN bonds on the PBN-19 skeleton realizing n-doping. The doping did not significantly disturb the π–π stacking and crystallization of PBN-19 and thus led to high thermoelectric performance. The covalent bonding of dopants on the polymer probably inhibited their diffusion out of the polymer matrix and thus slowed down the dedoping process. This work provides some new insights into the n-doping of organic thermoelectric materials.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
MOLECULAR CRYSTALS AND LIQUID CRYSTALS
·
2023
·
IF 0.7
Yajie Yang,Jinghua Zhao,Wei Liu,Yi Li,Yonggang Yang
A cholesteric liquid crystal (CLC) mixture was prepared using a photoisomerizable chiral dopant and acrylates. With extending the irradiation time of a 365-nm UV light, the Bragg reflection band of the CLC mixture shifted to long wavelength. After photopolymerization, a polymer-stabilized CLC (PSCLC) film was obtained. The colorful PSCLC patterns with glass microspheres on the surface were prepared by controlling the competition between the photoisomerization of the chiral dopant and the photopolymerization of the acrylates. Due to the retroreflective property, the patterned PSCLC films can be applied as the traffic signs and for advertisement.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
SYNTHETIC METALS
·
2020
·
IF 3.286
Ke Qu,Yuqi Bai,Xiyan Gao,Miao Deng
Graphite and multiwall carbon nanotube (MWCNT) served as dual dopants to prepare the composite with poly (aniline- co - o -methoxyaniline) copolymer electrochemically. The aniline to o -methoxyaniline monomer feed ratio was screened, with 4 to 1 monomer ratio being optimal. The supercapacitive properties of the prepared dual dopant-doped composite as electrode materials have been investigated and yielded a large specific capacitance of 535.0 F/g under 1.0 A/g current density and showed excellent rate performance, even with large current densities applied (up to 50.0 A/g). The composite remained to give a relatively stable specific capacitance of more than 200.0 F/g after 500 galvanostatic charge-discharge cycles, which afforded better and/or comparable performance compared with other polyaniline-based composite. The composite’s morphological features were characterized with scanning electron microscopy. The results from this study will be significant for the development of conducting polymer-based energy storage materials.
研究领域:
材料科学
·
能源存储
·
电化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）