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Auger Ionization Beats Photo‐Oxidation of Semiconductor Quantum Dots: Extended Stability of Single‐Molecule Photoluminescence 下载免费PDF全文
Shin‐ichi Yamashita Morihiko Hamada Prof. Shunsuke Nakanishi Hironobu Saito Prof. Yoshio Nosaka Dr. Shin‐ichi Wakida Dr. Vasudevanpillai Biju 《Angewandte Chemie (International ed. in English)》2015,54(13):3892-3896
Despite the bright and tuneable photoluminescence (PL) of semiconductor quantum dots (QDs), the PL instability induced by Auger recombination and oxidation poses a major challenge in single‐molecule applications of QDs. The incomplete information about Auger recombination and oxidation is an obstacle in the resolution of this challenge. Here, we report for the first time that Auger‐ionized QDs beat self‐sensitized oxidation and the non‐digitized PL intensity loss. Although high‐intensity photoactivation insistently induces PL blinking, the transient escape of QDs into the ultrafast Auger recombination cycle prevents generation of singlet oxygen (1O2) and preserves the PL intensity. By the detection of the NIR phosphorescence of 1O2 and evaluation of the photostability of single QDs in aerobic, anaerobic, and 1O2 scavenger‐enriched environments, we disclose relations of Auger ionization and 1O2‐mediated oxidation to the PL stability of single QDs, which will be useful during the formulation of QD‐based single‐molecule imaging tools and single‐photon devices. 相似文献
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Frontispiece: Auger Ionization Beats Photo‐Oxidation of Semiconductor Quantum Dots: Extended Stability of Single‐Molecule Photoluminescence 下载免费PDF全文
Shin‐ichi Yamashita Morihiko Hamada Prof. Shunsuke Nakanishi Hironobu Saito Prof. Yoshio Nosaka Dr. Shin‐ichi Wakida Dr. Vasudevanpillai Biju 《Angewandte Chemie (International ed. in English)》2015,54(13)
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Feng Jiang Douglas I. Trupp Norah Algethami Haining Zheng Wenxiang He Afaf Alqorashi Chenxu Zhu Chun Tang Ruihao Li Junyang Liu Hatef Sadeghi Jia Shi Ross Davidson Marcus Korb Alexandre N. Sobolev Masnun Naher Sara Sangtarash Paul J. Low Wenjing Hong Colin J. Lambert 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(52):19163-19169
Together with the more intuitive and commonly recognized conductance mechanisms of charge‐hopping and tunneling, quantum‐interference (QI) phenomena have been identified as important factors affecting charge transport through molecules. Consequently, establishing simple and flexible molecular‐design strategies to understand, control, and exploit QI in molecular junctions poses an exciting challenge. Here we demonstrate that destructive quantum interference (DQI) in meta‐substituted phenylene ethylene‐type oligomers (m‐OPE) can be tuned by changing the position and conformation of methoxy (OMe) substituents at the central phenylene ring. These substituents play the role of molecular‐scale taps, which can be switched on or off to control the current flow through a molecule. Our experimental results conclusively verify recently postulated magic‐ratio and orbital‐product rules, and highlight a novel chemical design strategy for tuning and gating DQI features to create single‐molecule devices with desirable electronic functions. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(25):7232-7235
To enable the investigation of low‐affinity biomolecular complexes with confocal single‐molecule spectroscopy, we have developed a microfluidic device that allows a concentrated sample to be diluted by up to five orders of magnitude within milliseconds, at the physical limit dictated by diffusion. We demonstrate the capabilities of the device by studying the dissociation kinetics and structural properties of low‐affinity protein complexes using single‐molecule two‐color and three‐color Förster resonance energy transfer (FRET). We show that the versatility of the device makes it suitable for studying complexes with dissociation constants from low nanomolar up to 10 μm , thus covering a wide range of biomolecular interactions. The design and precise fabrication of the devices ensure simple yet reliable operation and high reproducibility of the results. 相似文献
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Ahmet Atilgan Esra TanriverdiEik Ruslan Guliyev T. Bilal Uyar Sundus Erbas‐Cakmak Engin U. Akkaya 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(40):10854-10857
A ligand incorporating a dithioethenyl moiety is cleaved into fragments which have a lower metal‐ion affinity upon irradiation with low‐energy red/near‐IR light. The cleavage is a result of singlet oxygen generation which occurs on excitation of the photosensitizer modules. The method has many tunable factors that could make it a satisfactory caging strategy for metal ions. 相似文献
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Takanori Harashima Yusuke Hasegawa Satoshi Kaneko Manabu Kiguchi Tomoya Ono Tomoaki Nishino 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(27):9207-9211
Single‐molecule devices attract much interest in the development of nanoscale electronics. Although a variety of functional single molecules for single‐molecule electronics have been developed, there still remains the need to implement sophisticated functionalization toward practical applications. Given its superior functionality encountered in macroscopic materials, a polymer could be a useful building block in the single‐molecule devices. Therefore, a molecular junction composed of polymer has now been created. Furthermore, an automated algorithm was developed to quantitatively analyze the tunneling current through the junction. Quantitative analysis revealed that the polymer junction exhibits a higher formation probability and longer lifetime than its monomer counterpart. These results suggest that the polymer provides a unique opportunity to design both stable and highly functional molecular devices for nanoelectronics. 相似文献
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Jindong Wang Fangxia Shen Zhenxing Wang Gen He Jinwen Qin Nongyi Cheng Maosheng Yao Lidong Li Xuefeng Guo 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(20):5138-5143
Probing interactions of biological systems at the molecular level is of great importance to fundamental biology, diagnosis, and drug discovery. A rational bioassay design of lithographically integrating individual point scattering sites into electrical circuits is capable of realizing real‐time, label‐free biodetection of influenza H1N1 viruses with single‐molecule sensitivity and high selectivity by using silicon nanowires as local reporters in combination with microfluidics. This nanocircuit‐based architecture is complementary to more conventional optical techniques, but has the advantages of no bleaching problems and no fluorescent labeling. These advantages offer a promising platform for exploring dynamics of stochastic processes in biological systems and gaining information from genomics to proteomics to improve accurate molecular and even point‐of‐care clinical diagnosis. 相似文献