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排序方式: 共有90条查询结果,搜索用时 15 毫秒
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Muhammad Usman Khan Muhammad Yasir Mehboob Riaz Hussain Zainab Afzal Muhammad Khalid Muhammad Adnan 《International journal of quantum chemistry》2020,120(22):e26377
The development of organic electron acceptor materials is one of the key factors for realizing high-performance organic solar cells (OSCs). Nonfullerene electron acceptors, compared to traditional fullerene acceptor materials, have gained much impetus owing to their better optoelectronic tunabilities and lower cost, as well as higher stability. Therefore, 5 three-dimensional (3D) cross-shaped acceptor materials having a spirobifullerene core flanked with 2,1,3-benzothiadiazole are designed from a recently synthesized highly efficient acceptor molecule SF(BR) 4 and are investigated in detail with regard to their use as acceptor molecules in OSCs. The density functional theory (DFT) and time-dependent DFT (TDDFT) calculations have been performed for the estimation of frontier molecular orbital (FMO) analysis, density of states analysis, reorganization energies of electron and hole, dipole moment, open-circuit voltage, photo-physical characteristics, and transition density matrix analysis. In addition, the structure-property relationship is studied, and the influence of end-capped acceptor modifications on photovoltaic, photo-physical, and electronic properties of newly selected molecules ( H1-H5 ) is calculated and compared with reference ( R ) acceptor molecule SF(BR) 4 . The structural tailoring at terminals was found to effectively tune the FMO band gap, energy levels, absorption spectra, open-circuit voltage, reorganization energy, and binding energy value in selected molecules H1 to H5 . The 3D cross-shaped molecules H1 to H5 suppress the intermolecular aggregation in PTB7-Th blend, which leads to high efficiency of acceptor material H1 to H5 in OSCs. Consequently, better optoelectronic properties are achieved from designed molecules H1 to H5 . It is proposed that the conceptualized molecules are superior than highly efficient spirobifullerene core-based SF(BR) 4 acceptor molecules and, thus, are recommended to experiments for future developments of highly efficient solar cells. 相似文献
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Mondal Imdadul Hoque Rangan Latha Uppaluri Ramagopal V. S. 《Journal of Thermal Analysis and Calorimetry》2021,145(5):2389-2403
Journal of Thermal Analysis and Calorimetry - Drying characteristics of horticultural produce often target studies on the process parameters so as to derive useful data for the development of... 相似文献
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Amphiphilic liquid‐crystalline 4‐miktoarm star copolymers with a siloxane junction leading to cylindrically nanostructured templates for a siloxane‐based nanodot array
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Md Asadul Hoque Hideaki Komiyama Hiroki Nishiyama Keiji Nagai Takehiro Kawauchi Tomokazu Iyoda 《Journal of polymer science. Part A, Polymer chemistry》2016,54(9):1175-1188
Well‐defined A3B‐, A2B2‐, and AB3‐type 4‐miktoarm star copolymers (Mn = 10,500–16,200, Mw/Mn = 1.16–1.18) consisting of poly(ethylene oxide) (PEO) and polymethacrylate bearing an azobenzene mesogen (PMA(Az)) as the arms and cyclotetrasiloxane as the core unit were synthesized using a combined route composed of a thiol‐ene click reaction and atom transfer radical polymerization. Microphase‐separated structures of the star copolymers in thin films with a thickness of approximately 100 nm were investigated by GISAXS and TEM. The A3B‐type star‐(PEO)3[PMA(Az)]1 copolymer formed a more highly ordered PEO cylinder array with perpendicular alignment in the PMA(Az) matrix than that of the corresponding linear‐type block copolymer. The center‐to‐center distance of the PEO cylinders and the cylinder diameter were 13 and 4 nm, respectively. The highly ordered star‐(PEO)3[PMA(Az)]1 thin film was directly transferred to a siloxane‐based nanodot array by oxygen reactive ion etching. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1175–1188 相似文献
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In the present work, we have critically examined the origin of strong two-photon transition probability of a donor-acceptor substituted bisanthene molecule that imitates a small piece of edge passivated (4, 4) graphene nanoribbon. In our calculations, we have considered -OMe, and -NH(2) as donors and -NO(2) as an acceptor. The one- and two-photon absorption parameters are evaluated using state-of-the-art linear and quadratic response theory, respectively, and all these calculations are carried out within the framework of time dependent density functional theory. To give a proper judgment on our findings, we have used the long-range corrected CAMB3LYP functional for all of the time dependent calculations. The present investigation reveals that the bisanthene molecule with three pairs of donor/acceptor moiety has a lower two-photon transition probability than that of a suitably designed bisanthene with only a single pair of donor/acceptor moiety. This in silico observation is consistent for all of the donor/acceptor moieties chosen in the present work. A comprehensive analysis at the two state model level of theory clearly offers us a verdict that by placing the donor/acceptor moiety in a suitable position of bisanthene, we can create a significant asymmetry in the electron density in the first excited state, which eventually leads to a significant difference in the ground and excited state dipole moment and is attributed to the higher two-photon transition probability of a particular bisanthene with a single pair of donor/acceptor moiety than bisanthene with three pairs of donor/acceptor. 相似文献
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Archiv der Mathematik - We investigate the class number one problem for a parametric family of real quadratic fields of the form $$\mathbb {Q}( \sqrt{m^2+4r})$$ for certain positive integers m and r. 相似文献
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Considerable attention has previously been given to the single-vendor single-buyer integrated inventory problem, but there has been very little work on the integrated single-vendor multi-buyer case. Although the Joint Replenishment Problem applies in that case, it has not dealt with delivering a single product to multiple buyers when the set-up and inventory costs to the vendor are included. Assuming a close relationship between a manufacturer and buyers for a costless way of benefit sharing, three models are developed, two of which transfer with equal batches (part of a lot) and the third with unequal batches of the product. Optimal solution techniques are presented, a sensitivity analysis of the techniques is carried out, and several numerical problems are solved to support the analytical findings. A comparative study of the results shows that the supply by unequal batches performs better. This study also highlights the limitation of methods used in obtaining the least minimal total cost in the single-vendor single-buyer scenario, and the benefit of an integrated inventory is also discussed. 相似文献
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S. Scheriau M. Kriegisch N. Mehboob R. Pippan 《Journal of magnetism and magnetic materials》2010,322(20):2984-2988
Five sets of soft-magnetic metals, such as pure Fe, pure Ni, Fe-3 wt% Si, Fe-6.5 wt% Si and Fe-17 wt% Co, were subjected to high pressure torsion (HPT) up to strain levels where a saturation of the microstructural refinement is observed. Following HPT at 77, 293 and 723 K, transmission electron microscopy (TEM) was used to study the grain size and grain shape of the severely deformed metals. The coercivity HC was characterized in a magnetic closed system by using ring shaped samples. Magnetic measurements obtained on ring shaped samples give a much higher accuracy for determining the coercivity. Depending on the material the mean microstructural sizes in the steady state vary from 300 nm at 723 K to 30 nm at 77 K, respectively. The coercivity of the deformed materials first increases with decrease in grain size. Once the crystallite size is far below 100 nm the coercivity shows a strong decrease. 相似文献
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