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151.
Dynamic Photoswitching of Electron Energy Levels at Hybrid ZnO/Organic Photochromic Molecule Junctions 下载免费PDF全文
Qiankun Wang Giovanni Ligorio Valentin Diez‐Cabanes David Cornil Björn Kobin Jana Hildebrandt Marco Vittorio Nardi Melanie Timpel Stefan Hecht Jérôme Cornil Emil J. W. List‐Kratochvil Norbert Koch 《Advanced functional materials》2018,28(28)
The functionality of interfaces in hybrid inorganic/organic (opto)electronic devices is determined by the alignment of the respective frontier energy levels at both sides of the heterojunctions. Controlling the interface electronic landscape is a key element for achieving favourable level alignment for energy and charge transfer processes. Here, it is shown that the electronic properties of polar ZnO surfaces can be reversibly modified using organic photochromic switches. By employing a range of surface characterization techniques combined with density functional theory calculations, it is demonstrated that self‐assembled monolayers (SAMs) of photochromic phosphonic acid diarylethenes (PA‐DAEs) can be employed to reversibly change the electronic properties of polar ZnO/SAM structures by light stimuli. The highest occupied molecular orbital level of PA‐DAE is raised by 0.7 eV and the lowest unoccupied one lowered by 0.9 eV, respectively, upon illumination by ultraviolet light and the levels shift back to their original position upon illumination by green light. The results thus provide a pathway to tailor hybrid interface electronic properties in a dynamic manner upon simple light illumination, which can be exploited to reversibly tune the electrical properties of photoswitchable (opto)electronic devices. 相似文献
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153.
Andreas Kolmer Dr. Volker Schmidts Dr. Peter Monecke Prof. Dr. Stefan Hecht Prof. Dr. Christina M. Thiele 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(41):14545-14554
Stimuli responsive compounds and materials are of high interest in synthetic chemistry and materials science, with light being the most intriguing stimulus due to the possibility to remote control the physicochemical properties of a molecule or a material. There is a constant quest to design photoswitches with improved switching efficiency and especially diarylethene‐type switches promise photo cyclization quantum yields up to unity. However, only limited attention has been paid towards the influence of the solution conformation on the switching efficiency. Here, we describe a detailed NMR spectroscopic investigation on the conformational distribution of bridge‐substituted dithienylcyclopentenes in solution. We could discriminate between several photoactive and photoinactive as well as two diastereomorphous conformations and show that the trends observed in the switching efficiency match the conformer populations obtained from state of the art NMR parameters in solution. 相似文献
154.
Dragos Mutruc Alexis Goulet‐Hanssens Sam Fairman Sebastian Wahl Annett Zimathies Christopher Knie Stefan Hecht 《Angewandte Chemie (International ed. in English)》2019,58(37):12862-12867
A two‐component core–shell UiO‐68 type metal–organic framework (MOF) with a nonfunctionalized interior for efficient guest uptake and storage and a thin light‐responsive outer shell was prepared by initial solvothermal MOF synthesis followed by solvent‐assisted linker exchange. The bulky shell linker features two tetra‐ortho‐fluorinated azobenzene moieties to exploit their advantageous photoisomerization properties. The obtained perfect octahedral MOF single crystals can be switched repeatedly and with an unprecedented efficiency between E‐ and Z‐rich states using visible light only. Due to the high photoswitch density per pore of the shell layer, its steric demand and thus molecular uptake (and release) can be conveniently modulated upon green and blue light irradiation. Therefore, the “smart” shell acts as a light‐controlled kinetic barrier or “gate” for the diffusion of cargo molecules in and out of the MOF crystals. 相似文献
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157.
We present a numerical scheme to solve the incompressible Navier–Stokes equations with open boundary condition. After replacing the incompressibility constraint by the pressure Poisson equation, the key is how to give an appropriate boundary condition for the pressure Poisson equation. We propose a new boundary condition for the pressure on the open boundary. Some numerical experiments are presented to verify the accuracy and stability of scheme. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
158.
Hui-Ling Chen Heinrich Lünsdorf Hans-Jürgen Hecht Hsin Tsai 《Micron (Oxford, England : 1993)》2010,41(6):674-685
The somatic angiotensin I-converting enzyme (sACE; peptidyl-dipeptidase A; EC 3.4.15.1) was isolated from pig lung and purified to homogeneity. The purified enzyme has a molecular mass of about 180 kDa. Upon proteolytic cleavage, two approximately 90 kDa fragments were obtained and identified by amino-terminal sequence analysis as the N- and C-domains of sACE. Both purified domains were shown to be catalytically active. A 2.3 nm resolution model of sACE was obtained by three-dimensional electron microscopic reconstruction of negatively stained sACE particles, based on atomic X-ray data fitting. Our model shows for the first time the relative orientation of the sACE catalytically active domains and their spatial distance. 相似文献
159.
Tandel SK Khoo TL Seweryniak D Mukherjee G Ahmad I Back B Blinstrup R Carpenter MP Chapman J Chowdhury P Davids CN Hecht AA Heinz A Ikin P Janssens RV Kondev FG Lauritsen T Lister CJ Moore EF Peterson D Reiter P Tandel US Wang X Zhu S 《Physical review letters》2006,97(8):082502
We have identified two isomers in 254No, built on two- and four-quasiparticle excitations, with quantum numbers K pi = 8- and (14+), as well as a low-energy 2-quasiparticle Kpi = 3+ state. The occurrence of isomers establishes that K is a good quantum number and therefore that the nucleus has an axial prolate shape. The 2-quasiparticle states probe the energies of the proton levels that govern the stability of superheavy nuclei, test 2-quasiparticle energies from theory, and thereby check their predictions of magic gaps. 相似文献
160.