CRYSTAL GROWTH & DESIGN
·
2020
·
IF 4.089
Rui Wang,Fei Jia,Xuan Li,Ling Chen,Li-Ming Wu
The binary Bi/Se system with the general formula [Bi2]m[Bi2Se3]n exhibits intriguing properties, such as topological insulator and thermoelectric properties, and attracts intense attention. Herein, we found that the thermoelectric properties of BiSe at elevated temperatures have been deteriorated, because of the strong bipolar diffusion effect caused by its small band gap. Subsequently, with the aid of the crystal structure engineering strategy, we purposely involve less metallic [Bi2] layers in the crystal structure, and successfully synthesize a new n-type Bi8Se9 and investigate, for the first time, its thermoelectric properties. Bi8Se9 exhibits a significantly widened band gap from 0.085 eV in BiSe to 0.146 eV that effectively reduces the bipolar thermal conductivity from the 0.37 W m–1 K–1 in BiSe to 0.14 W m–1 K–1. As a result, Bi8Se9 realizes a balance between the electrical resistance, the Seebeck coefficient, and a lower thermal conductivity, and achieves a ZT value of 0.40 at 673 K, which is twice that of BiSe at 673 K.
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
Journal of Physical Chemistry C
·
2018
·
IF 4.484
Zhuo Wang,Binglong Lei,Xiaohong Xia,Zhongbing Huang,Kevin Peter Homewood,Yun Gao
CH3NH3PbI3-based perovskite solar cells have achieved great success in the past several years. However, their further large scale application is hindered by the toxicity of the Pb. Here, the existence of a stable perovskite structure with close to optimum optical properties for solar cells with Pb replaced by Bi was shown by theoretical modeling. It was found that the cubic perovskite BiI3 framework is maintained only when the polar organic group of CH3NH3+ is dissociated into neutral CH3NH2 molecule and hydrogen. The band gap of the neutral molecular filled CH3NH2BiI3 perovskite structure gives a value of 1.61 eV, which matches closely the solar spectrum with a maximum possible efficiency of 28.5% close to the Shockley–Queisser limit of 33% for a single stage cell, offering a new and promising lead-free route for perovskite solar cells.
研究领域:
材料科学
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
NATURE
·
2023
·Vol. 617
·期 7961
·488-492
·
IF 64.8
Zhong Yigui,Liu Jinjin,Wu Xianxin,Guguchia Zurab,Yin J.-X.,Mine Akifumi,Li Yongkai,Najafzadeh Sahand,Das Debarchan,Mielke Charles,Khasanov Rustem,Luetkens Hubertus,Suzuki Takeshi,Liu Kecheng,Han Xinloong,Kondo Takeshi,Hu Jiangping,Shin Shik,Wang Zhiwei,Shi Xun,Yao Yugui,Okazaki Kozo
The newly discovered kagome superconductors represent a promising platform for investigating the interplay between band topology, electronic order and lattice geometry 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 . Despite extensive research efforts on this system, the nature of the superconducting ground state remains elusive 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 . In particular, consensus on the electron pairing symmetry has not been achieved so far 18 , 19 , 20 , in part owing to the lack of a momentum-resolved measurement of the superconducting gap structure. Here we report the direct observation of a nodeless, nearly isotropic and orbital-independent superconducting gap in the momentum space of two exemplary CsV 3 Sb 5 -derived kagome superconductors—Cs(V 0.93 Nb 0.07 ) 3 Sb 5 and Cs(V 0.86 Ta 0.14 ) 3 Sb 5 —using ultrahigh-resolution and low-temperature angle-resolved photoemission spectroscopy. Remarkably, such a gap structure is robust to the appearance or absence of charge order in the normal state, tuned by isovalent Nb/Ta substitutions of V. Our comprehensive characterizations of the superconducting gap provide indispensable information on the electron pairing symmetry of kagome superconductors, and advance our understanding of the superconductivity and intertwined electronic orders in quantum materials.
研究领域:
凝聚态物理
·
超导物理
·
电子结构
·
量子材料
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry C
·
2023
·Vol. 11
·期 29
·10033-10042
·
IF 6.4
Jungang He,Xianchang Zhou,Ya Wang,Mohan Yuan,Hang Xia,Xiao Chen,You Ge,Xia Wang,Liang Gao,Jiang Tang
Lead sulfide (PbS) colloidal quantum dots (CQDs) are promising candidates for infrared photodetectors (PDs). However, solution-processed PbS CQDs with spectra ranging up to the mid-infrared range are completely absent because long-chain organic ligands capped on large size CQDs provide insufficient steric hindrance to separate the adjacent particles for dispersion in solvents, limiting their application in infrared PDs. Herein we report a strategy that addresses the extension of the response spectra of PbS CQDs by incorporating PbNO2 impurities. This is achieved by photo-carrier transition from the valence band (VB) of PbS CQDs to the unoccupied in-gap states (IGSs) near the conduction band. The device exhibits an obvious response with responsivity of 0.11 A W−1 and a detectivity of 5.38 × 108 Jones under the illumination of 3000 nm light rays at room temperature. Once the temperature decreased to 78 K, the device exhibited a response with a responsivity of 0.03 A W−1 and a detectivity of 3.77 × 108 Jones. The X-ray photoelectron spectroscopy results indicate that these IGSs are formed by using potassium nitrite (KNO2) to remove the oleate ligands and induce oxidation impurities on the CQD surface. Additionally, detailed characterization is carried out to investigate the mechanism of the infrared response of PbS CQDs. We are optimistic that this strategy could provide an alternative avenue toward the use of CQDs in optoelectronic devices with a broad response range.
研究领域:
材料科学
·
光电子学
✓ 已验证
产品关联
DOI
高影响因子
Materials Today Energy
·
2022
·
IF 9.257
Lulu Ren,Jingqi Qiao,Can Wang,Wenyue Zheng,He Li,Xuetong Zhao,Lijun Yang,Ruijin Liao
Since the promotion of the concept of nanodielectrics, the composite approach has long been considered as an effective way to improve the energy density of electrostatic capacitor films for energy storage applications. However, the selection criteria of nanofiller are blur in spite of multifarious attempts, such as Al 2 O 3 , HfO 2 , BaTiO 3 , TiO 2 , MnO 2 , MgO , etc. This paper is devoted to demonstrating the priority consideration of bandgap and permittivity in the filler selection of capacitive nanocomposite. The antagonistic effect between the bandgap and permittivity of fillers in the capacitive nanocomposite was revealed by the study of the physicochemical, dielectric , electric breakdown, and capacitive energy storage properties of polyetherimide (PEI) nanocomposites, i.e., PEI/ZrO 2 , PEI/SiO 2 , and PEI/TiO 2 nanocomposites with systematically varied bandgap and permittivity. It is found that the ZrO 2 nanofillers combine a wide bandgap and moderate permittivity; hence, the corresponding PEI/ZrO 2 nanocomposite shows the highest discharged energy density over PEI/SiO 2 and PEI/TiO 2 nanocomposite. Specifically, the PEI/ZrO 2 nanocomposite exhibits a maximum discharged energy density of 6.15 J/cm 3 at an optimal filler content of 3 vol%, which is 57.7% higher than that of neat PEI.
研究领域:
材料科学
·
能源存储
✓ 已验证
DOI
高影响因子
Nature Communications
·
2016
·Vol. 7
·期 1
·1-8
·
IF 11.329
Du Zengyi,Yang Xiong,Lin Hai,Fang Delong,Du Guan,Xing Jie,Yang Huan,Zhu Xiyu,Wen Hai-Hu
In the field of iron-based superconductors, one of the frontier studies is about the pairing mechanism. The recently discovered (Li 1− x Fe x )OHFeSe superconductor with the transition temperature of about 40 K provides a good platform to check the origin of double superconducting gaps and high transition temperature in the monolayer FeSe thin film. Here we report a scanning tunnelling spectroscopy study on the (Li 1− x Fe x )OHFeSe single crystals. The tunnelling spectrum mimics that of the monolayer FeSe thin film and shows double gaps at about 14.3 and 8.6 meV. Further analysis based on the quasiparticle interference allows us to rule out the d -wave gap, and for the first time assign the larger (smaller) gap to the outer (inner) Fermi pockets (after folding) associating with the d xy ( d xz /d yz ) orbitals, respectively. The gap ratio amounts to 8.7, which demonstrates the strong coupling mechanism in the present superconducting system.
研究领域:
凝聚态物理
·
超导研究
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Applied Materials & Interfaces
·
2023
·
IF 9.5
Dong Fang,Yanfang Tan,Yuxuan Ren,Shuchao Zheng,Fengming Xiong,Anchen Wang,Kai Chang,Baoxiu Mi,Dapeng Cao,Zhiqiang Gao
Cs2SnI6 powder is, for the first time, solution-prepared via the formula CsI + SnI2 + I2 → Cs2SnI6. The product is highly pure and air/thermal stable. It is found that N,N-dimethylformamide (DMF) and methanol induce severe Cs2SnI6 deterioration with the appearance of a CsI phase in film preparation from Cs2SnI6 powder, while solvents of γ-butyrolactone (GBL) and ethylene glycol methyl ether (EGME) (Film-EGME) give better results. Then, by introducing EGME solvent, in situ preparation of Cs2SnI6 films (Film-1 to Film-4) is realized under solution reaction, which is found to be dominated by thermal dynamic process, i.e., highly pure/oriented Film-4 is obtained under the maximum reagent-concentration. Besides, for good reaction, the solubility of solvent should be balanced among all the reagents and products. Solid-state dye sensitized solar cells (ss-DSSCs) comprising a Cs2SnI6 electrolyte are investigated. The power conversion efficiencies (PCEs) of the ss-DSSCs based on solution-casted Film-EGME and the in situ-prepared Film-4 are 1.81% and 3.30%, respectively. Particularly, with the in situ prepared Cs2SnI6 films, it is found that the open circuit voltages of the ss-DSSCs are closely related to their gap states. When additive is added in Cs2SnI6 electrolyte, a PCE of 6.14% is obtained in an ss-DSSC. Our work highlights the importance of solvent in film preparation and the role of Cs2SnI6 gap states in device performance.
研究领域:
材料科学
·
能源技术
·
光伏器件
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MOLECULAR STRUCTURE
·
2025
·
IF 4.7
Hao Ai,Qiushuo Li,Qiong Xu,Xiangying Li,Degen Li,Qiong Wu
To elucidate the modulation mechanism of halogen substitution on the electronic structure and solid-state packing of half-Salen Schiff base complexes, a combination of single-crystal X-ray diffraction, spectroscopic characterization, and density functional theory (DFT) calculations was employed. The research reveals a subtle balance: constrained by the non-planar conformation of the ligand, chloro-substitution results in minimal perturbation of the frontier molecular orbitals (FMOs), with the HOMO-LUMO gap only slightly decreasing from 2.87 eV to 2.80 eV. In stark contrast, the intermolecular interactions are significantly enhanced. Hirshfeld surface analysis and binding energy (ΔE) calculations confirmed that the newly formed C–H···Cl and halogen-π non-covalent interactions increased the pathways for intermolecular interactions, strengthening the dimer binding energy from –23.67 kcal/mol to –25.90 kcal/mol. These findings deepen the understanding of the effects of halogen substitution and provide new experimental and theoretical evidence for the regulation of band gaps and intermolecular interactions in Schiff base complexes .
研究领域:
无机化学
·
配位化学
·
材料科学
·
物理化学
·
晶体工程
·
理论化学
✓ 已验证
产品关联
DOI
高影响因子
Inorganic Chemistry Frontiers
·
2025
·
IF 6.4
Tian-Tian He,Chun-Li Hu,Ya-Ping Gong,Jiang-Gao Mao,Fang Kong
In this work, we present a targeted design strategy that combines Group IIIA metal cation and fluorine anion to simultaneously enhance the band gap and birefringence in selenite-based system. Three new ultraviolet (UV) transparent selenite fluorides, SrAl(SeO3)F3 (1), BaAl(SeO3)F3(H2O)0.25 (2), and ZnGa(SeO3)2F (3), were successfully synthesized under mild hydrothermal conditions. Remarkably, all three compounds exhibit wide band gaps as well as large birefringence. In particular, ZnGa(SeO3)2F (3) demonstrates a pronounced birefringence value of 0.176 at 546 nm, representing the highest birefringence reported among all known selenites with a band gap above 5.0 eV. Theoretical investigations indicate that the strong optical anisotropy is predominantly attributed to the stereochemically active lone-pair electrons of Se(IV) cations. The [Zn2O8] dimers and the infinite [GaO4F]∞ chains in ZnGa(SeO3)2F (3) crucially facilitate the optimal spatial arrangement of [SeO3] groups. This study expands the structural diversity of selenite fluorides and provides an effective pathway for designing high-performance birefringent crystals suitable for UV applications.
✓ 已验证
产品关联
DOI
高影响因子
Inorganic Chemistry Frontiers
·
2025
·
IF 6.4
Taizhong Xiao,Wen Song,Chongbing Mou,Jinke Wang,Liang Xu,Yongjin Li,Rui Hu,Zhaoyi Yin,Zhengwen Yang,Jianbei Qiu,Zhiguo Song
Crystal field engineering is currently the most significant method for enhancing the near-infrared (NIR) emission intensity and thermal stability of Cr3+ ions. However, this approach is inevitably accompanied by a pronounced blue shift in NIR emission, presenting a considerable challenge for spinel phosphors to achieve efficient and stable long-wavelength NIR emission of Cr3+ ions due to the inherent limitations imposed by a strong crystal field. In this study, we propose a novel pivot-polyhedron linkage engineering strategy based on the LiZnNbO4 (LZNO) spinel crystal to tackle this issue. Supported by the X-ray diffraction (XRD) refinement data, density functional theory (DFT) simulation results and Debye temperature analysis results, our findings reveal that the substitution of [ZnO4] by [MgO4] generates a unique pivot–polyhedron linkage effect. This occurs because the [ZnO4] tetrahedra share angles but not edges with all other polyhedra. Consequently, the simple incorporation of Mg2+ ions leads to a significant increase in NIR emission intensity and thermal stability by enhancing structural rigidity and bandgaps. Simultaneously, this modification allows the weak crystal field of [NbO6] octahedra to be maintained adequately through anomalous lattice expansion and reduced symmetry, which effectively preserves the long-wavelength emission characteristics of Cr3+ ions. The results of our research will establish a distinct structural principle for Cr3+-activated NIR phosphors, facilitating the achievement of exceptional long-wavelength emission and thermal stability.
✓ 已验证
产品关联
DOI
高影响因子
Crystals
·
2018
·Vol. 8
·期 4
·165
·
IF 2.144
Xiaowen Wu,Xiaofeng Gu,Hui Pan,Yi Hu,Kui Wu
Two quaternary metal chalcogenides, Ba2AlSbS5and Ba2GaBiSe5, were successfully synthesized by solid-state reaction in sealed silica tubes. Both of them crystallize in the same orthorhombic space groupPnma, but they appear with obviously different construction features. For example, Ba2AlSbS5exhibits [SbS3]3−units and zero-dimensional (0D) [AlSbS5]4−clusters, which is different from those ([BiSe6]3−units and 1D∞[GaBiSe5]4−chains) of Ba2GaBiSe5. We also systematically investigated the entire series of Ba2MIIIMIII’Q5(MIII= Al, Ga, In; MIII’ = As, Sb, Bi; Q = S, Se, Te) compounds, and the results showed that the interconnection of MIIIQ4and MIII’Qn(n= 3, 5, 6) units can form three different structural types, including 0D [MIIIMIII’Q5] clusters, single [MIII’Q3] chains and isolated [MIIIQ4] units, or [MIIIQ3]nand [MIII’Q3]ndouble chains, which may be induced by the flexible coordination and on-link modes of MIII’ atoms. Spectral investigation shows that their bandgaps are about 2.57 eV for Ba2AlSbS5and 2.14 eV for Ba2GaBiSe5. Theoretical calculation was also used to analyze their structure-property relationships, and the results indicate that the title compounds exhibit larger birefringences (Δn> 0.10), thus having potential as the IR birefringent materials.
研究领域:
无机化学
·
材料科学
·
固体化学
·
光学材料
·
计算化学
✓ 已验证
DOI
高影响因子
ORGANIC ELECTRONICS
·
2018
·
IF 3.68
Xiaoli Liu,Lingqian Kong,Hongmei Du,Yan Zhang,Jinsheng Zhao,Yu Xie
Two novel soluble polymers, PD-1 and PD-2, were synthesized based on three kinds of monomers , including propylenedioxythiophene (ProDOT), diketopyrrolopyrrole (DPP) and benzodithiophene (BDT), via Stille coupling reaction with the feed ratios (ProDOT:BDT:DPP) of 3:4:1, and 1:2:1, respectively. Wherein, propylenedioxythiophene (ProDOT) and benzodithiophene (BDT) exist as the donor unit, and diketopyrrolopyrrole (DPP) as the acceptor units. Both of the two copolymers were characterized via 1 H NMR, FT-IR spectra, X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), spectroelectrochemistry , switching kinetics, colorimetry and thermogravimetric analysis . Electrochemical studies demonstrate that both copolymers have the ability of rapid doping and dedoping and excellent stability. PD-1 displays a brown color in the neutral state, and a light green color in the oxidized state, while PD-2 exhibits gray green color in the neutral state and a transparent light green color in the oxidized state. As the content of the DPP remains constant, the changes in the content of the ProDOT unit can effectively control the color changes of the copolymers without apparent changes in bandgap ( E g ) values, and subsequently lead to the fine tune of the other properties of the copolymers, such as optical contrast, response time and coloring efficiency. The E g values of PD-1 and PD-2 are 1.55 eV and 1.52 eV, respectively. The optical contrasts are 42.36% (1600 nm) for PD-1 and 67.74% (at 1620 nm) for PD-2, both are ideal candidate materials for the fabrication of near infrared devices. They also have moderate optical contrast in the visible region, with fast response time and high coloring efficiency.
研究领域:
材料科学
·
电化学
✓ 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）