Kumar, AshwaniShkir, MohdSomaily, H. H.Singh, K. L....
9页查看更多>>摘要:To make perovskite solar cells competitive and efficient, it is necessary to control the crystallinity along with full coverage of the used substrate. Nowadays, numerous techniques have applied to improve and control the crystallinity of fabricated perovskite films, but still, have the most critical issue for perceiving high-performance perovskite solar cells. Herein, a low-cost yet effective procedure has used to fabricate thin-films of methylamine lead halide (CH3NH3PbI3) perovskite semiconductor. Uniform and high-quality CH3NH3PbI3 perovskite thin films were successfully fabricated on a glass substrate using a modified drop-casting method. Morphological characterization has shown an extremely compact, highly crystalline, and dense microstructure pinhole-free thin-film without any impure phase. Compared to the spin coating method, thin-films processed have been exposed to retain an enhanced film quality with higher crystallinity. Furthermore, a voltage-current characteristic has shown that the photoconductivity significantly enhanced the films processed with this versatile method. These results were also validated by absorbance and photoluminescence measurements. Achieved results highlight the significance of this low-cost method for forthcoming high-performance photovoltaic devices based on CH3NH3PbI3 semiconductor thin films.
原文链接:
NSTL
Elsevier
Qian, YanyanJing, QunDuan, HaimingLee, Ming-Hsien...
7页查看更多>>摘要:As a significant nonlinear optical compound, phosphate has been wildly used in all kinds of advanced optical systems. In this work, the electronic structures, and optical properties of a series of XPO3F and X-3(PO4)(2) (X = Sn, Pb, Sr, Ba) compounds were investigated using the first-principles method in both molecular and crystal levels. The results show that introducing F atoms can lead to enhanced HOMO-LUMO gap and enlarged anisotropy of polarizability. The anionic groups give main contribution to the total birefringence of alkaline earth phosphate and fluorophosphate. As for the post-transition metal phosphate and fluorophosphate, both anionic groups and cation-centric polyhedra play a critical role in determining birefringence. The X-p (X = Sn, and Pb) states nearby the Fermi level are beneficial to get enhanced birefringence, but they do not play a vital role in determining total birefringence.
原文链接:
NSTL
Elsevier
Sanad, Moustafa M. S.Arafat, Shadia W.Heiba, Zein K.Elshimy, Hassan...
8页查看更多>>摘要:Development of nano-sized electrode materials with unique structural and electrical properties is urgently needed due to their vital roles in advanced energy storage systems. Adhering to that. Ni-doped Co9S8 nanoparticles were directly prepared by a facile solvothermal method for implementation as active anodes in rechargeable Li-ion batteries and supercapacitors. X-ray diffraction analysis using Rietveld method revealed a single Co9S8 phase with cubic structure (Fm (3) over barm), confirming the incorporation of Ni ions into the Co9S8 lattice replacing Co ions mainly at octahedral sites. The particle size and morphology were examined by HRTEM images taken at different magnifications. The XPS measurements verified the presence of Ni ions in the Co9S8 matrix and determined the cations oxidation states. The as-prepared nano-Ni@Co9S8 anode material delivered high discharge and charge capacities similar to 764 and 520 mAhg(-1), respectively in the initial cycle of Li-ion battery. The fabricated Ni@Co9S8 supercapacitor demonstrated good specific capacitance similar to 312 F g(-1) with high capacitance retention similar to 96% after 700 cycles which decreased to 206 F g(-1) after 1600 cycles. Meanwhile, a sharp loss in its capacitance by 36% was happened in the subsequent 900 cycles achieving about 206 F g(-1) after 1600 cycles.
原文链接:
NSTL
Elsevier
Ghafari, A.Khan, W.Janowitz, C.
7页查看更多>>摘要:Thermoelectric properties of SnSe like the maximum thermoelectric performance and the Lorenz number are obtained from density functional theory and Boltzmann transport theory. The transport properties have been engineered by assuming a rigid band shift for modeling the n- and p-type SnSe. In consistent with the experimental data close to the Fermi-level a two-valley valence-band structure along the Gamma-Z direction has been observed. Furthermore, our calculated lattice thermal conductivity along the three axes shows the same trend as the experimental data (i.e. increasing from the x to the y to the z-axis). The engineered power factor enables us to obtain the maximum figure of merit of 2.89 at 850 K in the n-type SnSe which is higher than experimentally achieved value of 2.6. Finally, our calculated Lorenz number L for the p-doped SnSe at 300 K is close to the value of 2.44 x 10(-8) W sigma K-2 from fundamental theory.
原文链接:
NSTL
Elsevier
Ameur, AnfelLagoun, BrahimKhelfaoui, FrihaSadouki, Ouafaa...
9页查看更多>>摘要:Rubidium fluoroiodate has been reported to be a potential mid-infrared nonlinear optical material, due to its second harmonic generation (SHG) and Laser damage threshold value of 156 MW/cm(2). In this study, the linear and nonlinear optical properties are investigated and analyzed using the density functional theory by full potential linearized augmented plane wave (FP-LAPW) and plane wave pseudo-potential (PP-PW). The FP-LAPW method is used to study the electronic properties and linear optical properties with the recently developed density functional of Tran and Blaha. Furthermore, optical features such as dielectric functions, absorption coefficient, refractive index, reflectivity, electron energy loss function are calculated for photon energies up to 40 eV. The elasticity, SHG response, linear electro-optical effect, and piezoelectricity are studied by the PP-PW approximation. Based on the semi-empirical relations, the Young's modulus, shear and bulk modulus, Poisson's ratio, anisotropic factors, sound velocities, Debye temperature, and hardness have been determined.
原文链接:
NSTL
Elsevier