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991.
Fengzhu Li Chaoshen Zhang Jin‐Hua Huang Haochen Fan Huijia Wang Pengcheng Wang Chuanlang Zhan Cai‐Ming Liu Xiangjun Li Lian‐Ming Yang Yanlin Song Ke‐Jian Jiang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(20):6760-6764
Tin‐based halide perovskite materials have been successfully employed in lead‐free perovskite solar cells, but the overall power conversion efficiencies (PCEs) have been limited by the high carrier concentration from the facile oxidation of Sn2+ to Sn4+. Now a chemical route is developed for fabrication of high‐quality methylammonium tin iodide perovskite (MASnI3) films: hydrazinium tin iodide (HASnI3) perovskite film is first solution‐deposited using presursors hydrazinium iodide (HAI) and tin iodide (SnI2), and then transformed into MASnI3 via a cation displacement approach. With the two‐step process, a dense and uniform MASnI3 film is obtained with large grain sizes and high crystallization. Detrimental oxidation is suppressed by the hydrazine released from the film during the transformation. With the MASnI3 as light harvester, mesoporous perovskite solar cells were prepared, and a maximum power conversion efficiency (PCE) of 7.13 % is delivered with good reproducibility. 相似文献
992.
Xiaomei Lian Jiehuan Chen Minchao Qin Yingzhu Zhang Shuoxun Tian Xinhui Lu Gang Wu Hongzheng Chen 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(28):9509-9513
The fabrication of high‐quality film with large grains oriented along the direction of film thickness is important for 2D Ruddlesden–Popper perovskite‐based solar cells (PVSCs). High‐quality 2D BA2MAn?1PbnI3n+1 (BA+=butylammonium, MA+=methylammonium, n=5) perovskite films were fabricated with a grain size of over 1 μm and preferential orientation growth by introducing a second spacer cation (SSC+) into the precursor solution. Dynamic light scattering showed that SSC+ addition can induce aggregation in the precursor solution. The precursor aggregates are favorable for the formation of large crystal grains by inducing nucleation and decreasing the nucleation sites. Applying phenylethylammonium as SSC+, the optimized inverted planar PVSCs presented a maximum PCE of 14.09 %, which is the highest value of the 2D BA2MAn?1PbnI3n+1 (n=5) PVSCs. The unsealed device shows good moisture stability by maintaining around 90 % of its initially efficiency after 1000 h exposure to air (Hr=25±5 %). 相似文献
993.
Wenwen Yi Qiao Li Tengfei Song Lei Chen Xing-Cong Li Zhizhen Zhang Xiao-Yuan Lian 《Tetrahedron》2019,75(9):1186-1193
New indole alkaloids streptoprenylindoles A–C (1–3) and diterpenoids 18-acetyl-cyclooctatin (8), 5,18-dedihydroxy-cyclooctatin (9), and 5-dehydroxy-cyclooctatin (10) were isolated from the culture of marine-derived Streptomyces sp. ZZ820, along with known 3-cyanomethyl-6-[3-methyl-2-butenyl]indole (4), N-(2-(1H-indol-3-yl)ethylacetamide (5), 1-acetyl-β-carboline (6), indole-3-methylethanoate (7), cyclooctatin (11), and chromomycin A3 (12). Their structures were elucidated by a combination of extensive spectroscopic analyses, ECD calculation, and the Mosher's method. Streptoprenylindoles A (1) and B (2) are enantiomers that were separated through the preparation of their Mosher esters. Three new diterpenoids (8–10) showed antibacterial activities against methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli with MIC values of 24.11–55.12?μM, while chromomycin A3 (12) showed potent antibacterial activities against MRSA (MIC: 0.59?μM) and E. coli (MIC 0.04?μM). 相似文献
994.
The small organic molecular Dioctylbenzothienobenzothiophene (C8‐BTBT) has been explored as hole transport material (HTM) to replace PEDOT:PSS in inverted perovskite solar cells (PVSCs). MAPbI3 perovskite films depositd onto C8‐BTBT are smooth and uniform, with negligible residual of PbI2 and large grain size even larger than 1 μm. Our champion C8‐BTBT based devices reached a high power conversion efficiency (PCE) of 15.46% with marginal hysteresis, much higher than that of 11.50% achieved using PEDOT:PSS. Besides, devices adopting C8‐BTBT as substrate show superior stability compared with the PEDOT:PSS based devices when stored under ambient conditions with a relative humidity of (25±5)%. 相似文献
995.
A fundamental problem regarding the Dirac quantization of a free particle on an () curved hypersurface embedded in N flat space is the impossibility to give the same form of the curvature‐induced quantum potential, the geometric potential as commonly called, as that given by the Schrödinger equation method where the particle moves in a region confined by a thin‐layer sandwiching the surface. This problem is resolved by means of a previously proposed scheme that hypothesizes a simultaneous quantization of positions, momenta, and Hamiltonian, among which the operator‐ordering‐free section is identified and is then found sufficient to lead to the expected form of geometric potential. 相似文献
996.
从理论上探讨了非线性弹性大变形材料应用于抗爆结构的可行性,为此,基于等效结构体系的分析原理,将两端固定铰支梁的横向和纵向位移表示为三角级数形式,应用第二类Lagrange方程建立了非线性大变形材料梁的非线性分析方法,并且用ABAQUS有限元软件中的超弹性材料模型验证了所提出的方法的有效性。对典型的爆炸荷载作用下非线性弹性大变形材料梁的抗爆特性进行了分析,讨论了动力放大系数和材料性质及动荷载之间的关系。结果表明:与线弹性小变形材料相比,非线性弹性大变形材料具有优良的抗爆特性,结构的抗爆能力随结构变形的增大而显著提高。 相似文献
997.
在面向节点群的混合网状应用层组播模型(Hybrid Mesh Application Multicast Model,HM-ALM)中设计并实现了确定性线性网络编码,探讨了网络编码对提高组播性能的作用.实验表明,网络编码能减少传输延迟和增强系统健壮性.使用网络编码后系统传输延迟减少了约50%;在系统动态变化时,正确接收数据的节点数可以达到最大值,系统能更快恢复稳定. 相似文献
998.
999.
Phase correction and resolution improvement of digital holographic image in numerical reconstruction with angular multiplexing 总被引:1,自引:0,他引:1
A phase correction method is presented to remove the phase slope of the sub-holograms caused by the multi-direction illumination on object in digital holography. To improve the resolution of the reconstructed holographic images, two sub-holograms are recorded by using angular multiplexing and their phase slope parameter is obtained by theoretical analysis. Introducing a phase correction parameter to this phase slope, the ideal complex reconstructed image can be obtained by superposing the reconstructed object wave fields of the two sub-holograms. Experimental results demonstrate that the resolution of the reconstructed image can be effectively enhanced. 相似文献
1000.