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排序方式: 共有347条查询结果,搜索用时 46 毫秒
21.
Yuan Jun Zhang Chujun Chen Honggang Zhu Can Cheung Sin Hang Qiu Beibei Cai Fangfang Wei Qingya Liu Wei Yin Hang Zhang Rui Zhang Jidong Liu Ye Zhang Huotian Liu Weifang Peng Hongjian Yang Junliang Meng Lei Gao Feng So Shukong Li Yongfang Zou Yingping 《中国科学:化学(英文版)》2020,63(8):1159-1168
Recent advances in material design for organic solar cells(OSCs) are primarily focused on developing near-infrared nonfullerene acceptors, typically A-DA′D-A type acceptors(where A abbreviates an electron-withdrawing moiety and D, an electron-donor moiety), to achieve high external quantum efficiency while maintaining low voltage loss. However, the charge transport is still constrained by unfavorable molecular conformations, resulting in high energetic disorder and limiting the device performance. Here, a facile design strategy is reported by introducing the "wing"(alkyl chains) at the terminal of the DA′D central core of the A-DA′D-A type acceptor to achieve a favorable and ordered molecular orientation and therefore facilitate charge carrier transport. Benefitting from the reduced disorder, the electron mobilities could be significantly enhanced for the"wing"-containing molecules. By carefully changing the length of alkyl chains, the mobility of acceptor has been tuned to match with that of donor, leading to a minimized charge imbalance factor and a high fill factor(FF). We further provide useful design strategies for highly efficient OSCs with high FF. 相似文献
22.
Hole transport in molecularly doped polymers (MDPs) is modelled as random walks in a bias field E over organic donors D embedded in a polymer matrix. Positional disorder for donor fraction p < 1 is represented by randomly placing donors at sites in a fcc lattice, while energetic disorder is given by a Gaussian distribution of site energies with width and spatial correlations in a sphere of radius R c . Random walks generated by Marcus or small polaron rates for steps between nearby donors yield the mobility w( E , T ). In addition to and R c , the rates depend on the parameters nand ufor the distance dependence and reorganization energy respectively. With tritolylamine (TTA) in polystyrene as the paradigm, a procedure is presented for fixing the interdependent parameters , u, nand R c that reproduce the field and temperature dependences of w( E , T ) over a wide range of p that includes dilute systems with different TTA packings enforced by saturated bonds. Positional disorder exceeds energetic disorder in dilute systems and yields constant w( E , T 0 ) near room temperature. Joint modelling of TTA and related systems accounts for the characteristic w( E , T ) of MDPs and substantially extends the picture of hopping between localized states, with nincreased by about 15% and reduced by about 25% from conventional analysis using the Gaussian disorder model. Similar parameter changes are expected in other MDPs based on the compensation temperature T 0 and on scaling TTA results. 相似文献
23.
24.
We prove a q-analogue of the Carter–Payne theorem in the case where the differences between the parts of the partitions are sufficiently
large. We identify a layer of the Jantzen filtration which contains the image of these Carter–Payne homomorphisms and we show
how these homomorphisms compose. 相似文献
25.
D. Sabourdy V. Kermène A. Desfarges-Berthelemot M. Vampouille A. Barthélémy 《Applied physics. B, Lasers and optics》2002,75(4-5):503-507
The coherent combining of two Nd:YAG lasers using a Vernier–Michelson-type cavity has been demonstrated. The spectral behaviour
and the energetic performance are reported. We firstly show that the combining efficiency is not strongly spoilt by the gain
imbalance between the two amplifying media, and secondly, that despite the interferometric nature of the cavity, the Vernier–Michelson
laser can withstand environmental perturbations without alteration in output power.
Received: 25 April 2002 / Revised version: 18 May 2002 / Published online: 25 September 2002
RID="*"
ID="*"Corresponding author. Fax: +33-5/5545-7253, E-mail: kermene@ircom.unilim.fr 相似文献
26.
Formulas are given for the calculation of some mixed moments of aggregative characteristics of a homogeneous Markov chain
for the polynomial scheme.
Translated fromStatisticheskie Metody Otsenivaniya i Proverki Gipotez, pp. 156–164, Perm, 1991. 相似文献
27.
28.
Boullet J Sabourdy D Desfarges-Berthelemot A Kermène V Pagnoux D Roy P Dussardier B Blanc W 《Optics letters》2005,30(15):1962-1964
Coherent combining is demonstrated in a clad-pumped Yb-doped double-core fiber laser. A slope efficiency of more than 70% is achieved with 96% of the total output power in the fundamental mode of one of the two cores. This high combining efficiency is obtained when both cores are coupled via a biconical fused taper in a Michelson interferometer configuration. 相似文献
29.
30.
A novel thin layer cell equipped with thin layer gas electrode (TLGE) was studied as electrochemical gas sensor for the measurement of dissolved oxygen in water or aqueous solutions. The working electrode (TLGE) is a hydrophobic gas diffusing electrode placed between the cell electrolyte and the solution to be tested. The hydrophobic pores in TLGE serve as a gas chamber. After the sampling period, in which the partial pressure of dissolved oxygen in test solution becomes in equilibrium with that in the gas chamber, the TLGE is polarized with square wave or linear potential signal. Then the Faradaic charge (Q) consumed in depletion of the oxygen contained in pores of TLGE is measured. The main merits of this system are good linearity between the partial pressure of dissolved oxygen in test solution and Q, low zero-reading, negligible liquid-gas difference, convenient calibration and very low temperature coefficient (ca. 0.5%/°C). This technique can also be applied to the measurement of oxygen partial pressure in gas phases. 相似文献