Zhang, Yi-ManJia, Zhan-JuZhao, Zong-Yan
5页查看更多>>摘要：Cu2ZnSnS4 (CZTS) is a complex quaternary compound semiconductor, it is easy to form secondary phases during preparation, like Cu2S and ZnS, and there are interfaces between these secondary phases and the matrix. The interfaces are also key factors in determining the photovoltaic performance of CZTS. So, we used the firstprinciples calculation method to research the interfaces between the secondary phase Cu2S, ZnS and CZTS thin films. The influence of the secondary phase is clarified by analyzing the interface electronic properties of secondary phase and CZTS. The existence of Cu2S secondary phase is harmless to the photovoltaic performance of CZTS, and can even promote the improvement of photovoltaic performance. Therefore, it is not necessary to avoid it when preparing CZTS films, and even it can be used. However, the existence of ZnS secondary phase is harmful to the photovoltaic performance of CZTS, which should be avoided when preparing CZTS films.
原文链接:
NSTL
Elsevier
Mostafavi, MinaTanreh, SepidehAstaraki, MohammadFarjah, Bahar...
7页查看更多>>摘要：The emerging field of nanobiotechnology has recently paid great deals of attention to the interface at which biomolecules interact with the surface of nanostructures to fabricate functional materials. In this work, the interaction between glycine and metal organic frameworks (MOFs) was investigated using dispersion-corrected DFT (DFT-D3) calculations. Strong interactions were predicted between the glycine and MOF-5 at the interaction energy of-45.251 kcal/mol. The accuracy of the current method was verified by experimental data and second-order Moller-Plesset perturbation theory. Electronic structures and atoms-in-molecules (AIM) analysis of the interface region indicated that the glycine tends to establish chemical bonds with the MOF-5. Furthermore, a strong interaction was observed between the tripeptide and MOF-5, mimicking the behavior of realistic biological systems. These results pave the way for further realistic investigations into the biomolecular-nanostructured material complexes for the purpose of developing nano-scaled drug delivery systems.
原文链接:- NSTL
- Elsevier
El-Metwally, E. G.Hegab, N. A.Mostfa, M.
10页查看更多>>摘要：Chalcogenide composition of Te81Ge15Bi4 was prepared by the melt quenching technique in bulk form and by the thermal evaporation method in thin film form. The amorphicity of the investigated composition was examined by X-ray diffraction (XRD) analysis. The actual percentage of the prepared film samples was checked by energy dispersive X-ray (EDX) spectroscopy. The transmittance T(lambda) of the investigated films in the thickness range from 143 nm to 721 nm was measured in the spectral range (400-2500 nm). Swanepoel's method was used to calculate the linear optical parameters (refractive index (n) and absorption index (k)) from the transmittance T(lambda) data. Both n and k are found to be independent of the film thickness through the studied range. The type of allowed transitions was examined and found to be indirect allowed transitions with an optical energy band gap g ) and the optical absorption edge (Ee) equal to 0.652 eV and 0.089 eV using Tauc's extrapolation procedure and Urbach tail, respectively. The optical conductivity copt of Te81Ge15Bi4 film samples increased with increasing the incident photon energy (hw). The optical dispersion parameters (Eo and Ed), the high frequency dielectric constant epsilon infinity, the average oscillator strength So, the lattice dielectric constant epsilon L, the ratio between the free charged carriers concentration and its effective mass N/m* were obtained from the analysis of the refractive index results. The other parameters related to dielectric constant epsilon 1, dielectric loss epsilon 2, dissipation factor tan delta, relaxation time z, volume energy loss (VELF) and surface energy loss (SELF) functions show a dependence on photon energy (hw) for all investigated films. The non-linear optical susceptibility and the non-linear index of refraction n2 were also calculated using the linear dispersion parameters.
原文链接:- NSTL
- Elsevier
Hu, NengwenHuang, YongfengWang, KunHu, Wangyu...
12页查看更多>>摘要：Roles of non-/symmetric triple and quadruple junctions on plasticity of ploycrystals are examined using phasefiled crystal model combined with an isovolumetric deformation technique. We designed four polycrystalline samples containing the four types of junctions respectively to simulate the deformation process under a strain rate comparable to practical situations. Our results uncover relationships between the ability of resistances to external deformations and the deformation mechanisms. For the ploycrystals containing quadruple junctions, the symmetric junction is beneficial to maintain the stability of the junctions during deformations, while asymmetric ones would be disjointed and result in formation and growth of sub-grains. For the polycrystals containing triple junctions, the stability of the junction is strongly related to the misorientation angles of the associated grains. The triple junction composed with high-angle GBs exhibits excellent stability under successive deformations and the deformation is dominated by GB migrations. Low-angle GBs migrate more easily than the high-angle ones.
原文链接:- NSTL
- Elsevier
Rahangdale, Khushbu K.Ganguly, Subhas
8页查看更多>>摘要：Double oxide perovskites are fabricated by modifying the one by the other oxide through the ionic substitution process. However, the dielectric performance of typical such compounds is poor in general. It is because of oxygen vacancies concentration (V(sic)) increases due to the ionic substitution, which affects the conduction of charge carriers. In this work, Ga, which is known to be an element with high oxygen affinity, was chosen to dope the equimolar BiMnO3-BaTiO3 ceramic to decrease V(sic) during the mechanochemical synthesis. Consequently, the dielectric loss (at 200 degrees C with 1 kHz frequency) of BiMn(1-0.2)Ga0.2O3-BaTiO3 ceramic has been observed to decreased from 1.68 to 0.98 as compared to pristine specimen. Also, the resistivity was found to be increased from 1.0225 x 10(10) to 5.6452 x 10(12). The x-ray diffraction (XRD) scan showed the formation of single-phase perovskite with pseudo-cubic structure and a Ga doping associated lattice distortion. X-ray photoelectron spectroscopy (XPS) analysis explored the charge neutrality reaction of the doped ceramic and the interference effect of Ga in the Mn3+ to Mn2+ transition in this ceramic. The results are discussed in the context of the role of Ga to improve the dielectric behaviour and thus be suitable for storage device applications.
原文链接:- NSTL
- Elsevier
Alshahrie, AhmedAl-Ghamdi, A. A.Abdel-wahab, M. ShMahmoud, Waleed E....
8页查看更多>>摘要：A new series of Ni1-xAlxO (0 <= x <= 0.023) films was prepared using the co-sputtering technique. The influence of the partial replacement of Ni-atoms by Al-atoms on the structure, growth orientation, and the lattice strain of NiO crystallites was emphasized. These films exhibit a cubic structure with preferential orientation along the (111) plane. The surface topography was investigated using atomic force microscopy and the lattice vibration was studied using Raman spectroscopy. The optical absorption spectroscopy indicated that the sputtered films depict a direct bandgap energy in the range of 3.31-3.03eV. Likewise, the influence of the inclusion of Al in NiO on the localized states is premeditated in terms of Urbach energy. The photoluminescence measurements divulged that the sputtered films contain oxygen vacancies, nickel vacancies, and interstitial oxygen defects. On the other hand, the incorporation of Al-atoms in the Ni-sites leads to the improvement of the electrical conductivity. The optoelectronic properties of the Ni1-xAlxO (0 <= x <= 0.023) films were studied. The photo-detection mechanism of the constructed Ag/n-si/Ni1-xAlxO/Ag photodiodes was investigated. It was found that the Ni1-xAlxO (0 <= x <= 0.023) films exhibited a very fast photo-detection response of 2s and a high sensitivity of 3 x 10(-4) A cm(-2).sun(-1) with high stability and reproducibility.
原文链接:- NSTL
- Elsevier
Rambabu, A.Raju, K. C. James
5页查看更多>>摘要：Samarium substituted SBTi (SrBi3.25Sm0.75Ti4O15) thin films were deposited in the temperature range of 675-750 degrees C on amorphous substrates using radio frequency (RF) sputtering technique. Amorphous to preferred crystalline nature and single phase formation was identified by X-ray diffraction analysis. Atomic force microscopy was used to capture the surface morphology and calculate the grain size. Microwave dielectric properties of SrBi3.25Sm0.75Ti4O15 thin films were investigated at 10 & 20 GHz. The highest dielectric constant (similar to 118 @ 10 GHz, 104 @ 20 GHz) was obtained for films deposited at 725 degrees C with preferred orientation. Nanoindentation and scratch tests were performed using nanoindentation technique in order to evaluate the nanomechanical properties of the SrBi3.25Sm0.75Ti4O15 thin films. The best hardness similar to 9.6 GPa and Young's modulus similar to 120 GPa was observed for the films deposited at 750 degrees C. This study explored that the films with preferred orientation have potential applications in ferroelectric random access memories and actuators.
原文链接:- NSTL
- Elsevier
Rijckaert, HannesPremcheska, SimonaMohanty, SonaliVerduijn, Joost...
10页查看更多>>摘要：UiO-66-NH2 is a well-known Zr-MOF with a high surface area and good chemical stability, which is often employed for catalysis. The biological applications of Zr-MOFs are less often explored, however it has already been shown that they can be used for drug loading and release. In this work we show that UiO-66-NH2 (referred to as nano-MOF throughout the work) can be a host for accommodating beta-NaYF4:Er,Yb@beta-NaYF4 nano thermometers as well as gold nanoparticles (AuNPs) which can potentially take on the role of nanoheaters for plasmon-induced hyperthermia. Such a hybrid material can be made in an easy two step approach and yields nano-sized porous composites. At the same time, it could potentially still be used for drug delivery. A lipid bilayer is wrapped around the nano-MOF composites to further improve their biocompatibility with the human body. The hybrid composite shows good thermometry in the physiological range when dispersed in water.
原文链接:- NSTL
- Elsevier
Kamble, S. A.Phase, D. M.Ghorui, S.Bhattacharjee, D....
6页查看更多>>摘要：Electron emission properties of lanthanum hexaboride are dependent on the crystal structure as well as stoichiometric ratio of boron and lanthanum. Present research deals with the influence of carbon diffusion on the stoichiometric LaB6 synthesized using arc plasma gas phase condensation process. Nanocrystalline LaB6 has been synthesized using arc plasma at different plasma powers viz 2-3.4 kW. Further, an inclusion of carbonaceous species from the graphite anode with increasing plasma power and its correlation with stoichiometry has been elucidated. X-ray photo-electron spectroscopic technique has been used for the identification of surface chemistry of the synthesized powders and more effectively to infer the stoichiometry i. e. ratio of B:La in the samples synthesized with increasing plasma in put power. The influence of plasma parameters on the work function of the synthesized nanoparticles has also been elucidated using Ultraviolet Photoelectron Spectroscopy (UPS).
原文链接:- NSTL
- Elsevier
Zhou, ZijieHe, YueWang, Quan
7页查看更多>>摘要：Magnetoelectric materials have shown great application prospects in the fields of new magnetoelectric devices, spintronic devices, high-performance information storage, and processing. The application of new magneto electric materials to fabricate devices with superior performance and excellent quality is of great significance. In this work, the sol-gel method was employed to prepare PZT film on Pt substrate and the CrTe2 film by micro mechanical exfoliation was transferred to the PZT film. Combined with magnetron sputtering technology, the device was fabricated by depositing Au electrodes on the CrTe2/PZT composite film. The hysteresis loops and I-V characteristic curves of CrTe2/PZT composite films were measured at room temperature and ambient conditions. The results show that the residual polarization intensity and coercive field voltage of the composite film are decreased compared with the single-phase PZT. The preparation of a new magnetoelectric CrTe2/PZT composite film was realized. With the increase of CrTe2 coverage rate from 0 to 24% under Au electrode, the critical conduction voltage Vc decreases from 7.1 V to 5.2 V, and the leakage current increases from 50 mu A to 90 mu A at room temperature and ambient conditions. Herein, the influence mechanism of CrTe2 films with different areas on the leakage characteristics of PZT films and the model of the leakage characteristics have been systematically studied. Our results broaden the scope of future device applications based on magnetoelectric CrTe2/PZT composite films.
原文链接:- NSTL
- Elsevier
