Journal of Materials Chemistry C最新文献

{"title":"Theoretical analysis of optical and thermoelectric characteristics of TinO2n−1","authors":"S. Vahid Hosseini, Mohaddeseh Abbasnejad, Mohammad Reza Mohammadizadeh","doi":"10.1039/d4tc02505a","DOIUrl":"https://doi.org/10.1039/d4tc02505a","url":null,"abstract":"This study investigates the optical and thermoelectric properties of metallic (cubic TiO, monoclinic TiO, and γ-Ti<small>₃</small>O<small>₅</small>) and semiconducting (Ti<small>₂</small>O<small>₃</small>, α-Ti<small>₃</small>O<small>₅</small>, β-Ti<small>₃</small>O<small>₅</small>, Ti<small>₄</small>O<small>₇</small>, and Ti<small>₅</small>O<small>₉</small>) phases of Ti<small>_<em>n</em></small>O<small>_{2<em>n</em>−1}</small>, using various functionals including PBE, mBJ, PBE+<em>U</em>, and YS-PBE0. The YS-PBE0 and random phase approximation approaches accurately predict the electronic and optical bandgaps for semiconducting phases, which align well with the experimental data. For the case of semiconducting phases, two significant optical absorption peaks are identified: one in the infrared due to (t<small>_2g</small>–e<small>_g</small>) interband transitions and another in the ultraviolet due to O-2p to Ti-3d intraband transitions. The semiconducting phases demonstrate impressive Seebeck coefficients (800–1200 μV K<small>⁻¹</small>), driven by large effective mass and flat bands near the Fermi level. The electronic relaxation times are estimated to be 10<small>⁻¹⁴</small> to 10<small>⁻¹⁶</small> seconds for Ti<small>_<em>n</em></small>O<small>_{2<em>n</em>−1}</small> structures. Although the thermoelectric figure of merit of Ti<small>_<em>n</em></small>O<small>_{2<em>n</em>−1}</small> phases is low (&lt;1), there is possibility for improvement through optimizing carrier concentration. These findings suggest that Ti<small>_<em>n</em></small>O<small>_{2<em>n</em>−1}</small> can be considered as potential materials for thermoelectric applications.","PeriodicalId":84,"journal":{"name":"Journal of Materials Chemistry C","volume":null,"pages":null},"PeriodicalIF":7.393,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142259510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sensitizer-rich core–shell–shell upconversion nanoparticles for enhancing luminescence by spatial separation","authors":"Yujiao Zhang, Pengli Wang, Jiaxin Li, Jia Geng, Cuisong Zhou","doi":"10.1039/d4tc02830a","DOIUrl":"https://doi.org/10.1039/d4tc02830a","url":null,"abstract":"Lanthanide-doped upconversion nanoparticles (UCNPs) play an important role in sensing. However, the application of UCNPs is hampered due to their generally low luminescence intensity. In this paper, the NaYbF<small>₄</small>@NaYF<small>₄</small>:2%Er,20%Gd@NaYF<small>₄</small>:20%Gd (CSS) was designed to enhance the luminescence intensity, and the luminescence intensity was about 2.5 times that of traditional NaYF<small>₄</small>:20%Yb,2%Er,20%Gd@NaYF<small>₄</small>:20%Gd (CS). The enhancement of luminescence intensity was mainly attributed to three factors: (1) a larger absorption cross-section provided by a sensitizer-rich core (100% Yb<small>³⁺</small> doped), which was conducive to harvesting more near infrared light; (2) the spatial separation of the sensitizer and activator reduced harmful cross relaxation (CR); (3) the compact inert shell inhibited surface quenching. To further demonstrate the reasons for enhanced luminescence, the impact of different structures, the doping concentration of Yb<small>³⁺</small> and Er<small>³⁺</small>, and the thickness of the inert shell on optical properties were studied. Besides, the CSS can still maintain strong UCL after being treated with NOBF<small>₄</small> and dispersed in DMF. Based on this, a CSS-doped fibrous membrane (CDFM) with a promising hydrophobicity was fabricated and applied to detect single drop rhodamine B (RhB) taking advantage of the inner filter effect (IFE) with a low limit of 0.382 μM.","PeriodicalId":84,"journal":{"name":"Journal of Materials Chemistry C","volume":null,"pages":null},"PeriodicalIF":7.393,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142259518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"ESIPT-modulated HBT–o-carborane dyads with efficient aggregation-induced emission and acid-induced discolouration properties","authors":"Xueyan Wu, Chenxi Zhang, Na Li, Yan Lv, Jinxia Chi, Jixi Guo","doi":"10.1039/d4tc02889a","DOIUrl":"https://doi.org/10.1039/d4tc02889a","url":null,"abstract":"Non-ESIPT <strong>C-HBTP</strong> and ESIPT <strong>C-HBTO</strong> were designed and synthesized through nickel-catalyzed cross-coupling reactions, utilizing <em>o</em>-carborane and 2-(2′-hydroxy-phenyl)benzothiazole (HBT) as substrates. The photophysical characteristics of these compounds were thoroughly investigated through UV-vis absorption spectroscopy, fluorescence spectroscopy, and DFT calculations. <strong>C-HBTO</strong>, with its ESIPT properties, undergoes a structural transformation from an enol structure to a more stable ketone configuration. Additionally, <strong>C-HBTP</strong> and <strong>C-HBTO</strong> exhibited excellent aggregation-induced emission (AIE) properties and good quantum yields of 39.1% and 33.8% in the solid state, respectively.","PeriodicalId":84,"journal":{"name":"Journal of Materials Chemistry C","volume":null,"pages":null},"PeriodicalIF":7.393,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142259511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Delving into the bandgap tuning and nonlinear optical properties of hydrothermally synthesized pristine and boron doped molybdenum trioxide nanorods","authors":"Anjali Gopalakrishna Pillai, Mallikarjun Anandalli, M. S. Kala, Nandakumar Kalarikkal","doi":"10.1039/d4tc03081h","DOIUrl":"https://doi.org/10.1039/d4tc03081h","url":null,"abstract":"Nanostructures undergo significant changes in their electronic structure due to defects and disorders, which affect their electronic, structural, nonlinear and linear optical properties. This work highlights defect engineering as an effective tailoring approach to tune the structural and nonlinear and linear optical characteristics of boron-doped MoO<small>₃</small> (B–MoO<small>₃</small>) nanorods. The degree of boron (B) doping in the MoO<small>₃</small> lattice influences the bandgap and defect-tunable luminescence through the introduction of intermediate defect states. The pristine and doped MoO<small>₃</small> were synthesized using the hydrothermal method. Structural and morphological characterization techniques like XRD, Raman spectroscopy and FESEM were utilized to confirm the synthesis of the samples. The XPS analysis shows that defects like Mo interstitials, Mo vacancies and oxygen vacancies cause bandgap narrowing and PL intensity quenching. Optical properties were studied using UV-Vis absorption spectroscopy, revealing the inverse relationship between bandgap and the Urbach energy. Additionally, it was found that the phonon lifetime of the samples decreases with increasing doping concentration of B. The nonlinear optical investigation revealed that the third-order nonlinear optical parameters like saturation intensity (<em>I</em><small>_s</small>), nonlinear absorption coefficient (<em>β</em>) and optical limiting threshold (OLT) were improved with an increase in doping concentration and can be correlated with the impact of point defects that develop in the material. Specifically, the <em>β</em> value increased from 2.74 × 10<small>⁻¹⁰</small> to 5.19 × 10<small>⁻¹⁰</small> m W<small>⁻¹</small>, <em>I</em><small>_s</small> decreased from 3.81 × 10<small>¹²</small> to 9.6 × 10<small>¹¹</small> W m<small>⁻²</small>, and the OLT value decreased from 3.12 × 10<small>¹³</small> to 1.45 × 10<small>¹³</small> W m<small>⁻²</small> with the increase in doping concentration.","PeriodicalId":84,"journal":{"name":"Journal of Materials Chemistry C","volume":null,"pages":null},"PeriodicalIF":7.393,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142259514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Doubly charged single Weyl pair with complete spin polarization","authors":"Shiwei Zhang, Ying Liu, Xiaoming Zhang, Peng Wang, Anlong Kuang, Zhenxiang Cheng, Hongkuan Yuan, Tie Yang","doi":"10.1039/d4tc03286a","DOIUrl":"https://doi.org/10.1039/d4tc03286a","url":null,"abstract":"Topological states in crystalline materials have aroused significant research attention in recent years and have been expanded into intrinsic magnetic materials and high-order conditions. These investigations offer intriguing prospects from a fundamental physics standpoint. However, the combination of these aspects presents a great challenge as ideal material candidates with both clean band structures and simple topological configurations are extremely limited. Consequently, there have been only scarce investigations in this perspective. In this study, an ideal charge-two single Weyl pair with complete spin polarization has been unveiled in the Cu-doped lead apatite Pb<small>₉</small>Cu(PO<small>₄</small>)<small>₆</small>O. The topological surface states under the ±2 chiral topological charge can be prominently observed, making them immediately ready for experimental inspection since this material has already been synthesized. Detailed symmetry arguments and Hamiltonian analysis have been provided and, moreover, this simple topological configuration exhibits strong robustness against large strain conditions. These discoveries lay the groundwork for exploring the topological properties with both magnetic ordering and high-order dispersion. Importantly, the presented material candidates can instantly inspire the corresponding experimental advances and even revolutionize the field of spintronic topology.","PeriodicalId":84,"journal":{"name":"Journal of Materials Chemistry C","volume":null,"pages":null},"PeriodicalIF":7.393,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142259517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Extremely large magnetoresistance with coexistence of a nontrivial Berry phase in Nb0.5Ta0.5P: an experimental and theoretical study","authors":"Vinod K. Gangwar, Saurabh Singh, Swayangsiddha Ghosh, Srishti Dixit, Shiv Kumar, Prashant Shahi, Yoshiya Uwatoko, Sandip Chatterjee","doi":"10.1039/d4tc02170c","DOIUrl":"https://doi.org/10.1039/d4tc02170c","url":null,"abstract":"In our study, we focused on Weyl semimetals NbP and TaP, known for their remarkable magnetoresistance (MR) at low temperatures due to charge carrier compensation. We synthesized an intermediate compound, Nb<small>_0.5</small>Ta<small>_0.5</small>P, which also exhibits extremely large magnetoresistance (XMR) at low temperatures. Although its MR% is one order of magnitude lower than that of the parent systems, Nb<small>_0.5</small>Ta<small>_0.5</small>P demonstrates perfect charge carrier compensation up to 50 K. The magnetoresistance in this compound follows an <em>B</em><small>²</small> dependence and mirrors the classical carrier mobility's temperature dependence. We noticed a deviation from Kohler's rule in both instances, demonstrating the existence of multiple kinds of charge carriers. We conducted an analysis of Shubnikov–de Haas (SdH) oscillations to investigate the Fermi surface evolution and the presence of a nontrivial Berry phase in all three compounds. In Nb<small>_0.5</small>Ta<small>_0.5</small>P, quantum oscillations revealed multiple Fermi pockets. Additionally, density functional theory (DFT) calculations predicted bulk band structure features near the Fermi level, including band-crossing points. Changes in the density of states between the parent and doped systems were systematically observed, with the inclusion of spin–orbit coupling (SOC) revealing a band gap opening at Weyl node points. The significant enhancement in magnetoresistance observed in Nb<small>_0.5</small>Ta<small>_0.5</small>P at room temperature suggests promising avenues for exploring similar systems with suitable substitutions to develop new high-performance materials for industrial applications.","PeriodicalId":84,"journal":{"name":"Journal of Materials Chemistry C","volume":null,"pages":null},"PeriodicalIF":7.393,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study on the fluorescence enhancement characteristics of double-layer dislocated metal gratings","authors":"Dongliang Tian, Zhiyuan Wang, Bin Han, Jie Song, Chunying Liu, Zhihui Chen, Yang Wang","doi":"10.1039/d4tc01680g","DOIUrl":"https://doi.org/10.1039/d4tc01680g","url":null,"abstract":"In this paper, a double-layer dislocated metal grating hybrid structure is proposed, which is composed of a dislocated metal grating and an inclined dielectric grating. By locating the fluorescent material in the polymethyl methacrylate (PMMA) region of the hybrid structure, the structure achieves a remarkable far-field fluorescence directional emission enhancement. The effects of polarization state, metal grating period, and other parameters on directional fluorescence emission enhancement are studied by the finite-difference time-domain method. After optimizing the parameters, the fluorescence enhancement factor is as high as 1560-fold, of which the emission enhancement is 39-fold and the excitation enhancement is 40-fold. The far-field radiation angle is less than 18°, and the far-field radiation characteristics are improved. This work has application potential in fluorescence detection, imaging, and other luminescence devices.","PeriodicalId":84,"journal":{"name":"Journal of Materials Chemistry C","volume":null,"pages":null},"PeriodicalIF":7.393,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A lattice-enhanced light-driven terahertz meta-device with decoupled resonant modulation","authors":"Jing Zhang, Xilai Zhao, Jiangang Liang, Tong Cai, Chiben Zhang, Yifang Yuan, Hong Li, Xiao Yang, Xiaobao Zhang, Xi Wang, Tianwu Wang, Jing Lou","doi":"10.1039/d4tc01654h","DOIUrl":"https://doi.org/10.1039/d4tc01654h","url":null,"abstract":"Light-driven terahertz metasurface-based platforms, characterized by flexible and dynamic characteristics, exhibit significant potential in advancing optics applications. Tremendous effort has been devoted to exploring an effective way to boost the performance of optical elements. However, the typical mechanisms to design superior devices, including the nonlinear plasmonic, local-field construction, and Kerr effect are limited to the narrow working band and single function accompanied by efficiency loss, high-standard machining accuracy, and trade-offs between operating rate and signal-to-noise ratio. Here, a direct, efficient, and universal strategy for boosting the performance of light-driven devices is proposed to overcome these limitations. The performance of tri-function ultrafast switches operating at an ultrafast rate of 2 ps, including broadband single-amplitude modulators as well as decoupled resonant modulation with annihilation and enhancement, is manipulated by adjusting the lattice period. At all operating frequencies, the group delay characteristics are suppressed for high-fidelity communication. Furthermore, the loss-sensitive performance of the proposed metasurfaces, possessing highly precise sensing functions by light-driven calibration, could improve to 5/RIU through lattice enhancement. Thus, this work provides a simple and generalized paradigm for advancing ultrafast integrated optical devices and reusable precise sensors.","PeriodicalId":84,"journal":{"name":"Journal of Materials Chemistry C","volume":null,"pages":null},"PeriodicalIF":7.393,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Carbon nanotube graphene multilevel network based phase change fibers and their energy storage properties","authors":"Xiaoyu Yang, Jingna Zhao, Tanqian Liao, Wenya Li, Yongyi Zhang, Chengyong Xu, Xiaohua Zhang, Qingwen Li","doi":"10.1039/d4tc03006k","DOIUrl":"https://doi.org/10.1039/d4tc03006k","url":null,"abstract":"Phase change fibers with abilities to store/release thermal energy and responsiveness to multiple stimuli are of high interest for wearable thermal management textiles. However, it is still a challenge to prepare phase change fibers with superior comprehensive properties, especially proper thermal conductivity. Here, we report a cooperative <em>in situ</em> impregnation strategy to introduce graphene oxide (GO) and polyethylene glycol (PEG) together into the carbon nanotube (CNT) network during the expansion process and construct a 1D–2D multilevel skeleton, resulting in a CNT/GO/PEG composite phase change fiber. The presence of GO plays a more important role in increasing the interfacial contact and space volume, resulting in the characteristics of high loading (up to 96.8–98.4%), phase change enthalpy, and relatively lower thermal conductivity. Therefore, the CNT/GO/PEG phase change fiber demonstrates higher thermal efficiency during the exothermic process, showing good thermal management characteristics.","PeriodicalId":84,"journal":{"name":"Journal of Materials Chemistry C","volume":null,"pages":null},"PeriodicalIF":7.393,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221431","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mobile intrinsic point defects for conductive neutral domain walls in LiNbO₃.","authors":"Kristoffer Eggestad, Benjamin A D Williamson, Dennis Meier, Sverre M Selbach","doi":"10.1039/d4tc02856b","DOIUrl":"10.1039/d4tc02856b","url":null,"abstract":"<p><p>Conductive ferroelectric domain walls (DWs) hold great promise for neuromorphic nanoelectronics as they can contribute to realize multi-level diodes and nanoscale memristors. Point defects accumulating at DWs will change the local electrical transport properties. Hence, local, inter-switchable n- and p-type conductivity at DWs can be achieved through point defect population control. Here, we study the impact of point defects on the electronic structure at neutral domain walls in LiNbO₃ by density functional theory (DFT). Segregation of Li and O vacancies was found to be energetically favourable at neutral DWs, implying that charge-compensating electrons or holes can give rise to n- or p-type conductivity. Changes in the electronic band gap and defect transition levels are discussed with respect to local property engineering, opening the pathway for reversible tuning between n- and p-type conduction at neutral ferroelectric DWs. Specifically, the high Curie temperature of LiNbO₃ and the significant calculated mobility of O and Li vacancies suggest that thermal annealing and applied electric fields can be used experimentally to control point defect populations, and thus enable rewritable pn-junctions.</p>","PeriodicalId":84,"journal":{"name":"Journal of Materials Chemistry C","volume":null,"pages":null},"PeriodicalIF":5.7,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11414182/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142277412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}