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Mn-doping composition dependence of the structures, electrical and magnetic properties, and domain structure/switching of Aurivillius Bi5Ti3FeO15 films
摘要： Mn-doped Bi5Ti3FeO15 (BTFO) ?lms were prepared by a chemical solution deposition route. The e?ect of a series of di?erent Mn-doping concentrations from 0.05 to 0.4 on structures, electrical and magnetic properties, and domain structure/switching was systematically studied. Mn-doping into BTFO can avail the grain growth. Ferroelectric and dielectric properties are improved through Mn-doping, and the optimized Mn-doping content is 0.25 with remnant polarization of 17.2 μC/cm2 and permittivity of 371.2 at 10 kHz. Moreover, similar evolution of the permittivity and loss tangent with frequency to that of parent BTFO ?lms appears in the BTFMO ?lms when Mn-doping content is below 0.25, while obvious dispersion phenomena is demonstrated with further increasing Mn-doping content. A 180° domain structure and local ferroelectric switching are observed in all these Mn-doped BTFO thin ?lms, and the piezo-displacement can reach 416 p.m. in 0.15 Mn-doped BTFO ?lm. Finally, ferromagnetic properties appear in all these Mn-doped BTFO thin ?lms. The coercive ?eld shows weak temperature independence on Mn-doping contents, while the remnant magnetization is raised by Mn-doping.
关键词： Domain structure and switching,Dielectric response,Magnetic property,Ferroelectric property,Aurivillius compounds,Element doping
更新于2025-09-19 17:15:36
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Electrical, Structural, Optical, and Adhesive Characteristics of Aluminum-Doped Tin Oxide Thin Films for Transparent Flexible Thin-Film Transistor Applications
摘要： The properties of Al-doped SnOx films deposited via reactive co-sputtering were examined in terms of their potential applications for the fabrication of transparent and flexible electronic devices. Al 2.2-atom %-doped SnOx thin-film transistors (TFTs) exhibit improved semiconductor characteristics compared to non-doped films, with a lower sub-threshold swing of ~0.68 Vdec?1, increased on/off current ratio of ~8 × 107, threshold voltage (Vth) near 0 V, and markedly reduced (by 81%) Vth instability in air, attributable to the decrease in oxygen vacancy defects induced by the strong oxidizing potential of Al. Al-doped SnOx films maintain amorphous crystallinity, an optical transmittance of ~97%, and an adhesive strength (to a plastic substrate) of over 0.7 kgf/mm; such films are thus promising semiconductor candidates for fabrication of transparent flexible TFTs.
关键词： tin oxide,thin-film transistor,aluminum doping,adhesive property,oxide semiconductor
更新于2025-09-19 17:15:36
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Influence of solvent solubility parameter on the power law exponents and critical concentrations of one soluble polyimide in solution
摘要： Solvent species influence the interactions of dissolved polymers in solution and consequently induce changes in solution properties. A soluble polyimide was synthesized through polycondensation, and four solvents, namely, N,N-dimethylacetamide (DMAc), N-methyl pyrrolidone (NMP), N,N-dimethylformamide (DMF), and dimethyl sulfoxide (DMSO), were selected to investigate systematically the influence of solubility parameter on solution power law behaviors. The power law relationship between specific viscosity and concentration was established using rheology and applying concepts from the Zimm, Rouse-Zimm, and Doi-Edwards models. All power law exponents were higher than theoretical predictions, and in the three concentration regions, i.e. dilute, semidilute unentangled, and semidilute entangled, the exponents increase, decrease, and increase, respectively, with respect to solubility parameter. Arguments derived from the listed models are proposed to explain these trends. The influences of solubility parameter on the overlap and entanglement concentrations are also discussed.
关键词： Solubility parameter,Critical concentration,Polyimide,Power law exponent,Solution property
更新于2025-09-19 17:15:36
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Effect of (102) Diffracted Peak on Magnetic, Photoelectric, and Adhesive Characteristics of Fe <sub/>2</sub> Si Films
摘要： Fe2Si films with thicknesses from 100 nm to 600 nm underwent the following processes; (a) as-deposited films were maintained at room temperature (RT); (b) deposited films were post-annealed at 150 °C for 1 h, and (c) deposited films were post-annealed at a treatment temperature of 250 °C for 1 h. The X-ray diffraction (XRD) patterns of Fe2Si included significant (102) and (200) diffractions with corresponding peaks at 2θ are 44° and 53°, respectively. The (102) diffracted intensity and grain size of thicker and post-annealed Fe2Si thin films exceeded those of thinner and as-deposited Fe2Si thin films. The Fe2Si (102) peak revealed magneto-crystalline anisotropy, which reduced electrical resistivity and was associated with the highest low-frequency alternative-current (ac) magnetic susceptibility (χac). The maximum value of χac was reached at a thickness of 600 nm at the optimal frequency (fres) of 10 Hz, which generated maximized spin sensitivity. The resistivity (ρ) declined as the Fe2Si thickness and post-annealing temperature increased, because grain boundaries and the thin-film surface scattered the electrons. The 600 nm-thick Fe2Si thin film that was post-annealed at 250 °C had the lowest ρ of around 2.1 × 10^4 μΩ·cm. The as-deposited Fe2Si thin film with a thickness of 100 nm had the highest transmittance of approximately 48%. The maximum transmittance decreased slightly as the thickness increased and upon post-annealing. The surface energy of the as-deposited Fe2Si films exceeded those of post-annealed films, revealing that the adhesion of as-deposited Fe2Si films was stronger than that of post-annealed films owing to the degree of crystallinity.
关键词： Adhesion,Magneto Crystalline Anisotropy,Photoelectrical Property,Low-Frequency Alternative-Current Magnetic Susceptibility (χac)
更新于2025-09-19 17:15:36
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A quantitative structure–property study of reorganization energy for known p-type organic semiconductors
摘要： Intramolecular reorganization energy (RE), which quantifies the electron-phonon coupling strength, is an important charge transport parameter for the theoretical characterization of molecular organic semiconductors (OSCs). On a small scale, the accurate calculation of the RE is trivial; however, for large-scale screening, faster approaches are desirable. We investigate the structure–property relations and present a quantitative structure–property relationship study to facilitate the computation of RE from molecular structure. To this end, we generated a compound set of 171, which was derived from known p-type OSCs built from moieties such as acenes, thiophenes, and pentalenes. We show that simple structural descriptors such as the number of atoms, rings or rotatable bonds only weakly correlate with the RE. On the other hand, we show that regression models based on a more comprehensive representation of the molecules such as SMILES-based molecular signatures and geometry-based molecular transforms can predict the RE with a coefficient of determination of 0.7 and a mean absolute error of 40 meV in the library, in which the RE ranges from 76 to 480 meV. Our analysis indicates that a more extensive compound set for training is necessary for more predictive models.
关键词： molecular signatures,molecular transforms,reorganization energy,organic semiconductors,quantitative structure–property relationship
更新于2025-09-19 17:15:36
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Enhanced charge injection in 6, 13-bis(triisopropylsilylethylnyl)-pentacene field-effect transistors with a rhenium oxide buffer layer
摘要： We introduce a transition metal oxide, rhenium trioxide (ReO3), as a charge injection buffer layer for 6,13-bis(triisopropylsilylethylnyl)-pentacene (TIPS-pentacene) field-effect transistors (FETs). By inserting a ReO3 layer, a large energy barrier between silver source electrode and TIPS-pentacene layer was significantly reduced. While the TIPS-pentacene FETs showed low hole mobility (μh) of 0.25 cm2V?1s?1 and large threshold voltage (VTH) of ?25 V due to large contact resistance (RC) of 155 kΩ·cm, the TIPs-pentacene FETs with ReO3 decreased RC as low as 28 kΩ·cm. Thus, we can improve μh two times bigger (~ 0.46 cm2V?1s?1) and reduce VTH around 0 V. Together with these improved electrical characteristics, the TIPS-pentacene with ReO3 shows much stable operation under gate voltage bias stress condition. The shift of VTH and degradation of μh which were shown in the TIPS-pentacene FET without ReO3 is suppressed in the TIPS-pentacene FETs with ReO3 under both positive and negative bias condition.
关键词： ReO3,transistors,TIPS-pentacene,electrical property,thin-film,contact resistance,organic
更新于2025-09-19 17:15:36
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Cellulose nanofiber nanocomposites with aligned silver nanoparticles
摘要： Celluloses have attracted much attention as sustainable and abundant materials. Herein, we focus on nanocomposites based on the oxidation-treated nano-sized fibrillated celluloses, namely TOCNs. The silver nanoparticles (AgNPs) were prepared in TOCN aqueous dispersion. Generally, the AgNPs are quickly agglomerated after preparation. For the inhibition of the agglomeration of AgNPs, it is required that AgNPs were prepared under the chelation of TOCN, followed by reduction therein. Therefore, AgNPs possessed the nano-scaled radii and aligned along the TOCN from the atomic force microscopic measurements. The thermal stabilities and mechanical properties were increased. The anisotropic thermal conductivities originated from the orientation of TOCN in nanocomposites were observed. The loading of the large amounts of AgNP fillers led to the drastic increase of the thermal and electrical conductivities. The conductive paths of heat and electron were formed by the contact of AgNP with each other. We functionalized the TOCN papers through the loading of AgNPs and the obtained nanocomposites sheets served as conductors.
关键词： Cellulose nanofiber,mechanical property,TEMPO-mediated oxidation,silver nanoparticle,thermal conductivity
更新于2025-09-19 17:15:36
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Alkylamine-mediated synthesis and photocatalytic properties of ZnO
摘要： A simple approach to synthesize ZnO microstructures was reported using dodecylamine, hexadecylamine and oleylamine as template agents. The synthesized ZnO was characterized by XRD, FESEM, TEM, EDS mapping, FTIR, UV-vis DRS, Raman spectroscopy and BET analysis. Hierarchical oriented ZnO microstructures were obtained. The photocatalytic performance of ZnO prepared with different types of alkylamines was evaluated by the degradation of methylene blue (MB) and methyl orange (MO). The results suggested that alkylamine control the nucleation, growth and morphology of ZnO. The photocatalytic properties of ZnO on the degradation of MB and MO decreased with increasing the alkyl chain length in alkylamine.
关键词： photocatalytic property,controlled preparation,ZnO,alkylamine
更新于2025-09-19 17:15:36
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Size effect-enhanced thermoelectric properties of nanoscale Cu2-xSe
摘要： As a promising thermoelectric material, copper selenides have attracted the interest of researchers owing to their low cost, abundance in earth, environmental friendliness, and low thermal conductivity. In this study, copper selenide (Cu2-xSe) powders with controllable sizes from nanoscale to mesoscale were obtained by a facile one-pot solvothermal method. After treatment with spark plasma sintering, the nanoscale Cu2-xSe pellets exhibited excellent thermoelectric properties such as sharply reduced thermal conductivity and enhanced Seebeck coefficient as well as a suppressed electrical conductivity. The figure of merit (ZT) of the nanoscale Cu2-xSe reached up to ~1.51 at 873 K, which is about 2.67 times higher than that of the meso-Cu2-xSe. This study confirms that thermoelectric properties can be enhanced by the size effect.
关键词： size effect,solvothermal method,thermoelectric property,Copper selenide,nanoscale
更新于2025-09-19 17:15:36
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Theoretical study on the charge transport properties of three series dicyanomethylene quinoidal thiophene derivatives
摘要： It is very important to analyse the most advantageous connection style for quinoidal thiophene derivatives, which are used in n-type organic semiconductor transport materials. In the present work, the charge transport properties of three series of quinoidal thiophene derivatives, oligothiophene (series A), thienothiophene (series B) and benzothiophene (series C), are systematically investigated by employing the full quantum charge transfer theory combined with kinetic Monte-Carlo simulation. The single crystal structures of the molecules we constructed were predicted using the USPEX program combined with density functional theory (DFT) and considering the dispersion corrected. Our theoretical results expounded that how the different connection styles, including oligo-, thieno-, benzo- thiophene in the quinoidal thiophenes derivatives, effectively tune their electronic structures, and revealed that how their intermolecular interactions affect the molecular packing patterns and hence their charge transport properties by symmetry-adapted perturbation theory (SAPT). In the meanwhile we also elucidated the role of end-cyano groups in noncovalent interactions. Furthermore, it is clarified that the quinoidal thiophene derivatives show excellent carrier transport properties due to their optimal molecular stacking motifs and larger electronic couplings besides low energy gap. In addition, our theoretical results demonstrate that quinoidal oligothiophene derivatives (n=3~5) with more thiophene rings will have ambipolar transport properties, quinoidal thienothiophene and benzothiophene derivatives should be promising alternatives as n-type OSC. When we focused only on the electronic transport properties in the three series of molecules, quinoidal benzothiophene derivatives are slightly better than quinoidal oligothiophene and thienothiophene derivatives.
关键词： Crystal structure prediction,Dicyanomethylene quinoidal thiophene,N-type and ambipolar organic semiconductors,Charge transport property,Intermolecular interactions
更新于2025-09-19 17:15:36