Kumar, JagadishHembram, K. P. S. S.
6页查看更多>>摘要：We explore the interface properties of perovskite heterostructure CsPbBr3/CsPbI3 through first-principles calculations. The structural interface is formed by the bonding of Cs-Br and Cs-I with bond length of similar to 4.106 and 3.922 angstrom. The upshift of Goldsmith tolerance factor in the range 0.8 < t < 1 from t < 0.8 is revealed for the bi-layer interface, from bulk, reflecting the structural rearrangement from anisotropy to isotropy in confinement. The band gap arises mainly due to the energy difference of I-5p orbital than that of Br-4p at the valence band and Pb-6p at the conduction band. Heavier halide shows the red shift in the absorption spectra, for the pristine monolayer component. For the bilayer geometry, iodine contribution is more observed than that of bromine and the underlying interface properties may be useful for solar cell devices application.
原文链接:
NSTL
Elsevier
Ercan, IsmailKaygili, OmerKayed, TarekBulut, Niyazi...
14页查看更多>>摘要：In this study, the effects of Cu and Fe additives on the structural, dielectric, magnetic, thermal and morphology of hydroxyapatite (HAp) samples were investigated and reported in detail for the first time. The prepared systems were also modeled and examined theoretically. It can be said that both additives affect the thermal behavior of the HAp structure. The addition of Cu affected the morphology of submicron-sized particles with spherical-like shapes with a low degree of agglomeration. Diffuse reflection data revealed that the energy band gap values decreased as Cu was added to the Fe-based HAp structure. The dielectric constant (epsilon') had high values at low frequencies in all samples and decreased with increasing frequency. It could be concluded that Fe/Cu incorporation to hydroxyapatites enhanced its thermal, magnetic, and dielectric properties required for mimicking natural HAps to open a successful venue for medical application in the healing regeneration of bone.
原文链接:- NSTL
- Elsevier
Chandra, ParameshMandal, Swapan K.
5页查看更多>>摘要：Traditional perovskite solar cells have made tremendous progress in terms of efficiency in the past few years but the presence of toxic lead (Pb) has restricted their commercialization. We report here a process to fabricate MABiCl perovskite thin film based solar cell. The process shows some intriguing outcomes like uniform surface morphology of the perovskite layer, high open-circuit voltage and good fill-factor. The film shows improved uniform morphology and surface coverage with flakes (dimension 570 nm x 360 nm, thickness similar to 100-200 nm. The solar cell device shows an open-circuit voltage of about 496 mV and a fill factor 0.55. The improved morphology of the perovskite layer with reduced number of defects and charge traps possibly decreases the probability of recombination of photoexcited charge carriers. The result indicates that the process can be a good alternative to prepare lead free perovskite solar cells with improved performance.
原文链接:- NSTL
- Elsevier
Tsukasaki, TakashiMochida, NaokiFujita, MikiMakimoto, Toshiki...
4页查看更多>>摘要：In this study, electron traps in dilute GaAsN are investigated using the temperature dependence of electron concentration (n) and mobility (lie) for annealed heavily Si-doped GaAsN. The temperature dependence of n and lie depends on the annealing temperature, indicating that electrons are excited to the conduction band only from deep electron traps for heavily Si-doped GaAsN annealed at 580 degrees C. However, they are excited to the conduction band from both the deep electron traps and the shallow Si donor level for heavily Si-doped GaAsN annealed at 550 degrees C. The depth of the deep electron traps from the bottom of the conduction band for heavily Si-doped GaAsN annealed at 550 degrees C is almost equal to heavily Si-doped GaAsN annealed at 580 degrees C. The results demonstrate that these deep electron traps are inherent in dilute GaAsN because similar deep electron traps are also observed for the as-grown Si-doped GaAsN.
原文链接:- NSTL
- Elsevier
Lyu, Jing-JingJia, Shi-QingZou, Liang-Jian
7页查看更多>>摘要：In this letter we construct a superconductor-Kitaev quantum spin liquid (QSL)-metal/semimetal tunnelling junction. By the tunnelling current, conductance, and d2I/dV2, we investigate the spin dynamics of the Kitaev QSL. We show that the d2I/dV2 of the tunneling current has three characteristics: the spectral gap at 0.26K, the positions of peak and dip at omega approximate to 0.5K and 2.26K, respectively, except for an energy shift of superconducting gap Delta = 0.5K. These characteristics are the same as the spin correlations function of the Kitaev QSL. These results show that the tunnelling junction method could be a powerful tool in revealing the exotic spin excitation properties of the QSL materials.
原文链接:- NSTL
- Elsevier
Wang, YuSuo, HaoLi, LeipengWang, Guoqing...
5页查看更多>>摘要：The accurate measurement of temperature is of great importance in many fields ranging from industrial manufacture to our daily life, which can be finely implemented via the fluorescent intensity ratio (FIR) thermometry on the basis of Boltzmann distribution. Especially, the near-infrared (NIR)-emitting levels 4T2/2E of Cr3+ ion have recently emerged as the promising thermally coupled levels (TCLs), taking advantage of their superior optical property with high tunability. Herein, the crystal field strength around Cr3+ ions in doubleperovskite La2MgHfO6 have been elaborately modulated via varying the dopant concentration, which greatly affect the intensity ratio between the spin-forbidden 2E -> 4A2 and spin-allowed 4T2 -> 4A2 transitions. Thermal sensing behaviors based on the TCLs (4T2/2E) were evaluated and the relative sensitivity gradually grew with the increase of crystal field strength. Above results offer guiding insights into the sensitivity optimization of Cr3+based FIR thermometers, while providing the possibility of highly accurate measurement of temperature.
原文链接:- NSTL
- Elsevier
Feng, XuechaoLi, JunyuWu, Jie
4页查看更多>>摘要：We have investigated the magnetocaloric effect (MCE) of an Fe3GeTe2 single crystal near its Curie temperature (T-c) for magnetic field applying along the hard and easy magnetization directions. Magnetic susceptibility measurements indicate that it undergoes a ferromagnetic to paramagnetic phase transition around T-c similar to 200 K with high anisotropy. The maximum values of magnetic entropy change (Delta S-M) are estimated for magnetic field from 0-1 T to 0-7 T. Our main observation is that the Delta S-M along the easy axis is two to six times larger than that along the hard directions. We propose that magnetocrystalline anisotropy should be taken into consideration in order to maximize the performance of magnetic refrigerants.
原文链接:- NSTL
- Elsevier
Yuksel, O. FarukOzel, FarukAkin, UmmuhanTugluoglu, Nihat...
10页查看更多>>摘要：Penternary nanocrystals have attracted attention in recent years due to their attractive properties. For this reason, Cu2NiSn(SSe)(4) (CNTSSe) nanostructure, which is a novel candidate for penternary chalcogenide nano crystals, have been synthesized by hot-injection technique. The crystallographic structure and morphology of CNTSSe nanocrystals were investigated by XRD and TEM analysis. However, the overall composition and elemental mapping images of CNTSSe nanocrystals were analyzed by energy-dispersive spectroscopy. Then, the CNTSSe nanocrystals were produced by spin coating method onto glass substrates in thin film form. The optical properties were characterized by UV-Vis-NIR spectroscopy. The XRD analysis exhibited the formation of kesterite phase with peaks corresponding to polycrystalline CNTSSe nanocrystals with tetragonal structure in (312), (112), (220) planes. The nanocrystals have consisted of extremely distributed, quasispherical particles with an average diameter of 12 +/- 2 nm. Besides, the direct band gap and absorption coefficient of film were computed as 1.29 eV and over 10(4) cm(-1).
原文链接:- NSTL
- Elsevier
Vora-ud, AthornChaarmart, KongphopeKasemsin, WassanaBoonkirdram, Sarawoot...
6页查看更多>>摘要：Copper Iodide (CuI) transparent thin films were synthesized by using the as-deposited Cu thin film dip in the Iodine (I-2) solution (1% per 100 cc.) for 15s, 30s, and 60s within the liquid iodination method. The as-deposited Cu thin films on glass slide substrates as used were prepared by a dc magnetron sputtering method from the Cu target. The microstructure, morphology, and thermoelectric properties were studied by using X-ray diffraction (XRD) techniques, scanning electron microscopy (SEM), and the ZEM-3 method, respectively. The optical property of the film samples was determined from measured transmittance using a UV-visible spectrophotom-eter. The optical bandgap energy is 3.0 eV and the transmittance is around 80-95% for the thin film as dipped 30s. At room temperature, the power factor of Cul thin films were 14.71, 17.49, and 17.48 mu W m(-1) K-2 for as dipped 15s, 30s, and 60s, respectively.
原文链接:- NSTL
- Elsevier
Soltani, SaharRozati, Seyed MohammadAskari, Mohammad Bagher
8页查看更多>>摘要：In this present, a spinel cubic Co3O4 nanostructured thin film has been deposited by a simple and inexpensive spray pyrolysis method on preheated FTO substrate at different temperatures of the substrate (TS = 350 degrees C, 400 degrees C, 450 degrees C, and 500 degrees C). The surface, optical and structural properties of these films have been studied by FESEM, UV-Vis, and XRD analyses. According to these results the film has been deposited at TS = 400 degrees C chooses for electrochemical tests. The surface morphology investigated by FESEM and structural properties has been studied by XRD patterns. The grain size of samples was calculated by XRD patterns and FESEM images. The average grain size was about 30 nm, and the results of XRD and FESEM confirmed each other. UV-vis spectroscopy of these films shows that they have two absorption edges with direct and indirect bandgap at 2.2 and 1.5 eV, respectively. The electrochemical properties of this electrode have been analyzed by CV, impedance, and charge/discharge curve. The CV curve was investigated at different scan rates: 100, 80, 60, 40, 20, and 10 mv.s(-1). The specific capacitance of the above electrode was decreased by increasing the scan rate. The specific capacitance of this electrode was calculated by CV and charge/discharge curve and it was 1800 F/g. The electrochemical analysis shows that the capacity of this electrode decreases only 4% after 5000 cycles therefore it is a very stable electrode.
原文链接:- NSTL
- Elsevier
