Advanced Science
·
2020
·Vol. 7
·期 11
·1903493
·
IF 15.84
Sihui Li,Jiwu Xin,Abdul Basit,Qiang Long,Suwei Li,Qinghui Jiang,Yubo Luo,Junyou Yang
Lead-free chalcogenide SnTe has been demonstrated to be an efficient medium temperature thermoelectric (TE) material. However, high intrinsic Sn vacancies as well as high thermal conductivity devalue its performance. Here, β-Zn 4 Sb 3 is incorporated into the SnTe matrix to regulate the thermoelectric performance of SnTe. Sequential in situ reactions take place between the β-Zn 4 Sb 3 additive and SnTe matrix, and an interesting “core–shell” microstructure (Sb@ZnTe) is obtained; the composition of SnTe matrix is also tuned and thus Sn vacancies are compensated effectively. Benefitting from the synergistic effect of the in situ reactions, an ultralow κ lat ≈0.48 W m −1 K −1 at 873 K is obtained and the carrier concentrations and electrical properties are also improved successfully. Finally, a maximum ZT ≈1.32, which increases by ≈220% over the pristine SnTe, is achieved in the SnTe-1.5% β-Zn 4 Sb 3 sample at 873 K. This work provides a new strategy to regulate the TE performance of SnTe and also offers a new insight to other related thermoelectric materials.
研究领域:
材料科学
·
热电材料
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Advanced Ceramics
·
2021
·Vol. 10
·期 4
·809-819
·
IF 6.707
Yan Tianxiang,Chen Kaiyuan,Li Chengqi,Liu Min,Wang Jie,Fang Liang,Liu Laijun
(1− x )K 0.5 Na 0.5 NbO 3 − x Bi(Zn 2/3 Nb 1/3 )O 3 ((1− x )KNN− x BZN, x = 0.010, 0.015, 0.020, 0.025, and 0.030) lead-free ceramics were fabricated via a traditional solid-state method. The crystal structure, microstructure, dielectric, and conductivity behavior of this system were studied. Combined with X-ray diffraction (XRD) patterns, Rietveld refinement, and dielectric spectroscopy, an orthorhombic phase was determined for x = 0.010, an orthorhombic-tetragonal mixed phase was identified for x = 0.015, and a rhombohedral symmetry appears in 0.020 ⩽ x ⩽ 0.030. Both 0.98KNN−0.02BZN and 0.975KNN−0.025BZN ceramics exhibit stable permittivity and low dielectric loss tangent (tan δ ) in wide temperature ranges owing to the combination of rhombohedral-tetragonal step-like feature and the diffuse phase transition from tetragonal to cubic. The activation energies of dielectric relaxation and conductivity behavior at high temperatures initially decrease slightly, then drop sharply, and finally decline slowly, which could be attributed to microstructure morphologies and the concentration of oxygen vacancies.
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 LUMINESCENCE
·
2021
·
IF 3.599
Zixu Zhang,Xueyuan Guo,Keke Huang,Xiaoqi Sun,Xiaoming Li,Haibo Zeng,Xuanbo Zhu,Ying Zhang,Renguo Xie
Scintillators have recently attracted increased attention because of their potential applications in various fields, such as medical imaging, security, and nondestructive inspection . However, the response time of commercial scintillators is normally in microseconds or milliseconds only, a property that restricts their practical applications in high-resolution and dynamic X-ray imaging. Here, we report Rb 2 AgCl 3 crystals as an efficient scintillator material with ultrafast response time. The Rb 2 AgCl 3 crystals were found to have a one-dimensional structure and a bright-orange emission peak at 580 nm and a quantum yield of 60.0%. Experimental and computational studies revealed that the strong emission might have originated from self-trapping excitons that resulted into large Stokes shifts and high quantum efficiency. Upon X-ray excitation, the Rb 2 AgCl 3 crystals displayed a fast scintillation decay time of 9.5 ns and achieved a light yield of 18,300 photons MeV −1 . The ratio of light yield to decay time could reach up to 1926 photons MeV −1 ns −1 , which was higher than that of existing commercial scintillators. As a scintillator, Rb 2 AgCl 3 crystals are a promising material with potential applications in dynamic real-time imaging with a high spatial resolution owing to its nontoxicity, good stability, high light yield, and short decay time.
研究领域:
材料科学
·
医学成像
·
光学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2023
·Vol. 34
·期 6
·1-12
·
IF 2.8
Lin Wu,Yang Qingqing,Meng Bin,Ping Xinyu,Fang Congcong,Zhang Han,Chen Yingquan
A series of lead-free perovskite-structured dielectric ceramics of (1-x)Ba 0.6 Sr 0.4 Ti 0.7 Zr 0.3 O 3 -xBi(Li 0.5 Ta 0.5 )O 3 ((1-x)BSTZ-xBLT, x = 0, 0.10, 0.15, and 0.20) were prepared through solid-state reaction method combined with conventional sintering. Specifically, for x = 0, 0.10, 0.15, and 0.20, the samples of (1-x)BSTZ-xBLT were sintered in air for 8 h at 1500 °C, 1300 °C, 1200 °C, and 1150 °C, respectively. All samples possess a pure perovskite structure and achieve a high relative density of 93 ~ 95%. The average grain size of all samples falls within 1.74 ~ 2.67 μm, and all composition elements distribute uniformly. The addition of BLT is conducive to reduce the sintering temperature of BSTZ. The critical electric field corresponding to the saturation polarization intensity of BSTZ increases from 69.4 kV/cm to 88.9 kV/cm as x rises from 0 to 0.10. The dielectric permittivity of 0.85BSTZ-0.15BLT and 0.80BSTZ-0.20BLT keeps stable (∆ \(\varepsilon\) / \(\varepsilon\) 25 °C ≤ ± 15%) in the test temperature of − 100 ~ 350 °C. The activation energy ( \(E\) α ) of BSTZ enhances from 0.86 eV to 1.72 eV as x rises from 0 to 0.20, which contributes to the broadening of the band gap. These results suggest that (1-x)BSTZ-xBLT ceramics are promising candidates for high-temperature ceramic capacitors.
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 COLLOID AND INTERFACE SCIENCE
·
2022
·
IF 9.965
Lijun Wu,Song Zheng,Heng Lin,Shun Zhou,Ahmed Mahmoud Idris,Jin Wang,Sheng Li,Zhengquan Li
All-inorganic lead-free halide double perovskites have emerged as rising star photocatalysts to substitute the toxic lead-based hailed perovskites (LHPs) owing to their unique photophysical properties. Nevertheless, their photocatalytic activities toward CO 2 reduction are still far from comparable with the LHPs, associated with severe charge recombination and sluggish surface catalytic reaction . Herein, a delicate 0D/2D heterojunction of Cs 2 AgBiBr 6 /Bi 2 WO 6 (CABB/BWO) was assembled by in-situ growing cubic CABB nanocrystals on the flat surface of BWO nanosheets via a facile hot-injection method. Density functional theory (DFT) calculations disclose that the work function and Fermi level difference between CABB and BWO give rise to charge redistribution at the interface upon the formation of the heterojunction, creating an internal electric field (IEF). Upon light irradiation , the IEF enables the photogenerated electron transfer from BWO to CABB via direct Z-scheme electron transfer mode with striking spatial charge separation as verified by in-situ X-ray photoelectron (XPS) and electron spin resonance (ESR) spectra. Consequently, the CABB/BWO heterojunction realizes 7-fold higher photocatalytic activity than pristine CABB with significant electron consumption rate of 87.66 µmol g -1 h −1 under simulated solar light (AM 1.5G).
研究领域:
材料科学
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环境科学
·
化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Gang Liu,Huanghui Nie,Leiyang Zhang,Xinyu Zeng,Yazhong Zheng,Xinyu Chen,Xinran Wang,Kun Yu,Li Jin,Yan Yan
To acquire giant electric field-induced strain in non-Pb materials is attracting a great deal of attention in the past decade. In the current investigation, the crystal and domain structures as well as the electrical performances of (1- x ) (0.94Bi 0.5 Na 0.5 TiO 3 -0.06BaTiO 3 )- x NaTaO 3 (BNBT- x NT) specimens were systematically studied to achieve enhanced strain. The introduction of NT makes the phase structure transit from rhombohedral-tetragonal to pseudo-cubic structure. The original domain structure of BNBT is destroyed, and the disorder degree of the local structure increases. Simultaneously, the remnant polarization, coercive field, and piezoelectric coefficients were significantly decreased. The transition from ferroelectric to ergodic relaxation can be effectively modified, thus lowering the transition zone to room temperature. Finally, the BNBT-3NT ceramics achieve marked strain coefficients at room temperature, with a maximum strain of 0.394% under 65 kV/cm and a d 33 * of 606 pm/V.
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
高影响因子
CHEMISTRY-A EUROPEAN JOURNAL
·
2023
·Vol. 29
·期 40
·e202300667
·
IF 4.3
Peng Xu,Huang Ye,Yunpeng Yao,Tingting Zhu,Junhua Luo
Graphical Multifunctional material (benzylammonium) 4 AgBiBr 8 , which has a step-like dielectric phase transition at 383 K/387 K (cooling/heating) and excellent photoelectric properties, was obtained by using rigid benzylammonium cations as templates. Layered hybrid perovskites possess exceptional semiconductor features and structural versality, making them viable candidates for developing multifunctional dielectric phase-transition materials (PTMS). However, most PTMs based on layered hybrid perovskites still suffer from Pb toxicity and low operating temperature. The recently developed hybrid double perovskites provide a new routine to designed PTMs with desired working performance and environment-friendly chemical compositions. Herein, using rigid aromatic cations as templates, we have successfully synthesized a novel double perovskite (benzylammonium) 4 AgBiBr 8 ( 1 ), which consists of corner-sharing AgBr 6 and BiBr 6 layers and benzylammonium cations. Notably, 1 exhibits a high-temperature first-order reversible solid-state phase transition at 383/387 K (cooling/heating) and switchable dielectric performance around the temperature. Compared with the soft organic chain version of the compound, the phase transition temperature of 1 shows a large enhancement of 99 K, validating the correctness of the designing strategy. In addition, 1 also exhibits semiconductor characteristics with a calculated bandgap of 2.34 eV and an optical bandgap of 2.29 eV. Remarkably, the single crystal photodetector of 1 shows a low dark current (2.12×10 −13 A), a high on/off ratio (1.77×10 3 ), and a fast response ( τ rise =125 μs and τ decay =419 μs). Such a lead-free phase transition material combined with semiconductor properties provides a new strategy to develop environmentally friendly multifunctional materials.
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
iScience
·
2023
·
IF 5.8
Daofu Wu,Xiaoqing Liu,Changqing Tian,Jinchen Zhou,Junan Lai,Hongmei Ran,Bo Gao,Miao Zhou,Qiang Huang,Xiaosheng Tang
Summary Lead halide perovskites are prospective candidates for CO 2 photoconversion. Herein, we report copper-doped lead-free Cs 2 AgSbCl 6 double perovskite microcrystals (MCs) for gas-solid phase photocatalytic CO 2 reduction. The 0.2Cu@Cs 2 AgSbCl 6 double perovskite MCs display unprecedented CO 2 photoreduction capability with CO and CH 4 yields of 412 and 128 μmol g −1 , respectively. The ultrafast transient absorption spectroscopy reveals the enhanced separation of photoexcited carriers in copper-doped Cs 2 AgSbCl 6 MCs. The active sites and reaction intermediates on the surface of the doped Cs 2 AgSbCl 6 are dynamically monitored and precisely unraveled based on the in-situ Fourier transform infrared spectroscopy investigation. In combination with density functional theory calculations, it is revealed that the copper-doped Cs 2 AgSbCl 6 MCs facilitate sturdy CO 2 adsorption and activation and strikingly enhance the photocatalytic performance. This work offers an in-depth interpretation of the photocatalytic mechanism of Cs 2 AgSbCl 6 doped with copper, which may provide guidance for future design of high-performance photocatalysts for solar fuel production.
研究领域:
材料科学
·
环境科学
·
化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Shuaifei Mao,Mingqing Cui,Sheng Jiang,Pengfei Zhao,Jie Lao,Chunli Jiang,Chunhua Luo,Bobo Tian,Hechun Lin,Jadranka Travas-sejdic,Hui Peng,Chun-Gang Duan
The lead-free perovskite-inspired materials are regarded as one of the alternatives to lead-based perovskite for the preparation of neuromorphic devices due to their low toxicity, excellent optical and transport properties. Herein, a two-terminal artificial synapse was fabricated based on a novel lead-free halide Cu 2 AgBiI 6 thin film. The fabricated device exhibited the versatile synaptic behavior whether subjected to external electrical or optical stimulation benefitting from the excellent photoelectric characteristics of Cu 2 AgBiI 6 . Furthermore, the intrinsic photovoltaic feature of Cu 2 AgBiI 6 enabled the device with capabilities of operating in a self-powered mode under optical stimulation. The device successfully imitated the retina’s capacity for color perception by employing optical pulses of various wavelengths. The dependence of the device response on the optical pulse frequency allowed it to function as a high-pass filter for image sharpening. At last, the device was applied for the information encryption and decryption transmission based on a constructed password book including 128 common characters and numbers, which shows great potential for information encryption and decryption transmission. The comprehensive characters of the device display great superiority over other artificial synaptic devices.
研究领域:
神经形态计算
·
材料科学
·
光电学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Jingwen Lv,Simeng Song,Yan Jiao,Zhaoyu Yang,Yilin Zhang,Yingjie Fan,Chunlin Song,Gang Liu
A novel strategy of enhancing the dielectric and energy storage properties of Na 0.5 Bi 0.5 TiO 3 –BaTiO 3 (NBT–BT) ceramics by introducing a K 0.5 Na 0.5 NbO 3 (KNN) ferroelectric phase is proposed herein, and its underlying mechanism is elucidated. The lead-free KNN ceramic decreases the residual polarisation and increases the electric breakdown strength of the NBT–BT matrix through the simultaneous modification of its A-sites and B-sites. The obtained NBT−BT− x −KNN ceramics have a perovskite structure with unifying grains. A bulk 0.9NBT–BT–0.1KNN ceramic sample with a thickness of 0.2 mm possesses a high energy storage density of 2.81 J/cm 3 at an applied electric field of 180 kV/cm. Moreover, it exhibits good insulation properties and undergoes rapid charge and discharge processes. Therefore, the obtained 0.9NBT–BT–0.1KNN ceramic can be potentially used in high-power applications because of its high energy density , good insulation properties, and large discharge rate.
研究领域:
材料科学
·
能源存储
✓ 已验证
DOI
高影响因子
ACS Applied Electronic Materials
·
2022
·
IF 4.494
Chengyao Liang,Yanyi Huang,Yijie Shi,Daofu Wu,Qijie Chang,Bingsheng Du,Xuezheng Guo,Delin Kuang,Zhilin Wu,Chengjiu Zhao,Xiaosheng Tang,Jing Qiu,Yong He
A suitable humidity environment is of great significance to the healthy and comfortable life of urban residents, and the humidification effect of street trees is crucial for effectively regulating microclimates in big cities. Therefore, evaluating the humidification capacity among species is a rewarding research aiming at providing bases for selecting appropriate street tree species. The leaves of trees generate water vapor through transpiration to slowly increase the environmental humidity, and humidity sensors with giant response, excellent linearity, and reliable repeatability are more conducive to analyzing and evaluating the subtle process in detail. Here, the antisolvent method was adopted to simplify the synthesis process of lead-free K2CuBr3, and the fabricated impedance-type humidity sensor based on K2CuBr3 microrods satisfied these requirements. The all-inorganic lead-free halide K2CuBr3 overcomes two drawbacks, including the toxicity of Pb and the moisture instability of most reported halide perovskites used in the field of humidity sensing. The impedance variation exceeds 106 Ω (162 Ω to 182 MΩ), with the relative humidity varying from 12 to 95%. In addition, the analysis of the corresponding complex impedance spectroscopy revealed the sensing mechanism. The intrinsic properties of K2CuBr3 are reflected at low humidity, and the proton transfer gradually dominates the sensing paths with increasing humidity. Furthermore, the K2CuBr3 humidity-sensitive layer is employed to evaluate the transpiration of street trees for the first time, and the successful evaluation of the humidification effect indicates more applications of lead-free halides.
研究领域:
环境科学
·
材料科学
·
植物学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Binghao Cui,Zhangpan Shen,Jianguo Chen,Shuai Cheng,Jinrong Cheng
0.75BiFeO 3 -0.25BaTiO 3 lead-free ceramics have been considered promising candidates for high-temperature piezoelectric applications. However, their dielectric and piezoelectric properties severely degrade with increasing temperature. In this work, improved dielectric and piezoelectric thermal stability was obtained in CuO-modified 0.75BiFeO 3 -0.25BaTiO 3 ceramics. CuO addition increases the volume fraction of the rhombohedral phase in the 0.75BiFeO 3 - 0.25BaTiO 3 ceramics and makes the chemical heterogeneity disappear. The dielectric and piezoelectric anomalies are eliminated near 300 °C and return with CuO additions, and the temperature degradations of the dielectric constant and piezoelectric coefficient of 0.75BiFeO 3 -0.25BaTiO 3 ceramics with 0.008 mol CuO in the range from 25 to 400 °C decrease by 85% and 60%, respectively. Furthermore, the depoling temperature and piezoelectric coefficient of 0.75BiFeO 3 -0.25BaTiO 3 ceramics with 0.008 mol CuO are 570 °C and 131 pC/N, respectively. These results indicate that CuO addition is an effective approach to improve both the dielectric and piezoelectric thermal stability of 0.75BiFeO 3 -0.25BaTiO 3 ceramics.
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）