Single-molecule techniques offer a unique tool for studying the dynamical behavior of individual molecules and provide possibility to construct distributions from events rather than signal stemming an ensemble molecules. In biological systems, known their complexity, these make it possible gain insights into detailed spectrum molecular conformational changes activities. Here, we report on direct observation single lipase-catalyzed reaction extended periods time (hours), by using confocal...

Real-time measurement of the catalysis and substrate kinetics a single-enzyme hydrolysis reaction is demonstrated with confocal fluorescence microscopy (CFM; see picture, green=CFM beam). A single lipase shown to have broad range conformations; each conformation contributes overall enzymatic activity, an observation that often masked by ensemble measurements. Supporting information for this article available on WWW under http://www.wiley-vch.de/contents/jc_2002/2005/z460625_s.pdf or from...

Novel bisimide-fused acenes were synthesized via bismuth triflate mediated double-cyclization reaction of acid chlorides and isocyanates. Their optical electrical properties revealed significantly smaller HOMO-LUMO gaps compared with those their parent acenes. Fabricated OFET based on tetracene bisimide showed n-type outputs.

Most azobenzene derivatives are utilized as well-defined photoresponsive materials, but their emission properties have not been of great interest they relatively poor. Here, we report crystallization-induced (CIE) based on the suppression photoisomerization derivatives. Although these molecules show negligible in solution, microcrystals exhibit intense from moieties a result CIE. Upon rapid precipitation, fine particles with low crystallinity were kinetically formed and underwent CIE over...

Emission photon statistics of semiconductor nanocrystal quantum dots (QDs), including lead halide perovskite nanocrystals (PNCs), are important fundamental and practical optical properties. Single QDs exhibit high-probability single-photon emission owing to the efficient Auger recombination between generated excitons. Because rate depends on QD size, probability should be size-dependent. Previous studies have researched smaller than their exciton Bohr diameters (twice radius excitons). Here,...

We use single-molecule fluorescence lifetimes to probe dynamics of photoinduced reversible electron transfer occurring between triphenylamine (donor) and perylenediimide (acceptor) in single molecules a polyphenylenic rigid dendrimer embedded polystyrene. Here, individual donor-acceptor results delayed that is emitted with high photon count rate. By monitoring decay times on photon-by-photon basis, we find fluctuations both forward reverse spanning broad time range, from milliseconds...

To reveal the exciton dynamics, particularly multiexciton dynamics in single colloidal CdSe/ZnS quantum dots (QDs) interacting with localized surface plasmon resonance (LSPR) of silver nanoparticles (AgNPs), we investigated single-photon emission behavior fluorescence from QDs using a single-molecule spectroscopy technique combination femtosecond-pulsed laser excitation. By applying simultaneous measurements photon-correlation (photon antibunching), intensity, and lifetime to QD near AgNPs,...

We have fabricated well-defined nanostructures such as SiO2-coated Ag nanoparticles (NPs) connected with quantum dots (QDs) (Ag/SiO2-QDs) so to control the fluorescence enhancement induced by localized surface plasmon resonance. Namely, distance between NP and QD should be noted a controllable model investigate effect. Actually, highly monodispersed core was first coated five thicknesses of SiO2 shell, then QDs were specifically adsorbed onto amino-functionalized NPs. As result, intensity...

Single-molecule fluorescence spectroscopy was performed on a number of multi-peryleneimide substituted polyphenylene dendrimers for the purpose investigating parameters which influence efficiency as single-photon sources at room temperature. Analysis intensity, lifetime, and interphoton arrival time distribution revealed that all measured first-generation behave emitters when more than one chromophore is excited by single excitation pulse regardless constituent chromophores. This result...

Quantum dots-based electron donor-acceptor systems play a rising role in the design of renewable and carbon-free energy harvesting technologies. In this article, we discuss photofabrication fullerene-shelled quantum dots supramolecular nanoparticles, which fullerene shell acts as not only well-defined acceptor but also robust protecting layer against photocorrosion dot core. We evaluate ensemble single-molecule transfer from core to nanoparticles photocurrent response photoelectrochemical...

The enhancement of multiphoton emission from a single colloidal nanocrystal quantum dot (NQD) interacting with plasmonic nanostructure was investigated using silver-coated atomic force microscopy tip (AgTip) as the nanostructure. Using AgTip, which exhibited well-defined localized surface plasmon (LSP) resonance band, we controlled spectral overlap and distance between NQD AgTip. behavior when approaching AgTip at nanometer scale measured off-resonance (405 nm) (465 excitation LSP. We...

Singlets annihilated: A single-molecule fluorescence spectroscopic study of multichromophoric peryleneimide-substituted polyphenylene-core dendrimers under various conditions indicates that increased intersystem crossing (see graphic) as a consequence an annihilation process might represent general motif for photobleaching the first intensity levels in systems.

Single-photon emission behavior in the enhanced fluorescence from single colloidal quantum dots (QDs) near silver nanoparticles (AgNPs) was investigated using a molecule spectroscopy technique. It found that degree of enhancement QDs with AgNPs increased decrease lifetime and probability single-photon emission, is, highly shortened exhibited low emission. The present results yield new insights into fundamentals QD-metal nanostructure interactions, are also important to understand mechanism...

Time-resolved photoluminescence (PL) and transient absorption (TA) spectroscopy are conducted in order to get knowledge on the excited state of CdSe nanorods (NR), assess impact Au nanoparticles (NP) carrier dynamics hybrid Au-CdSe NRs. The decay measured solution show an increase non-radiative channels presence NPs, whose characteristic lifetimes vary from a few ps tens ps. ultrafast electron transfer NRs NPs efficiently competes with intraband relaxation dynamics, allowing observation...

The change of photon statistics in the fluorescence a single CdSe/ZnS core/shell colloidal nanocrystal quantum dot (NQD) accompanying atomic force microscopy (AFM) manipulation cubic Au nanoparticle (AuCube) was investigated to elucidate effect plasmonic nanostructures on multiexciton dynamics NQD. Upon coupling an AuCube well-defined size and shape, we directly observed conversion single-photon emission from individual NQD multiphoton emission, this accompanied by increase intensity...

Cesium lead halide (CsPbX3, X = Cl, Br, I) perovskite nanocrystals (NCs) exhibit outstanding photosensitizing properties, owing to their large absorption cross-section and high photoluminescence quantum yields. Consequently, coassemblies with functional organic dyes can be used establish energy conversion systems capable of sensitizing dyes. In coassembly, the self-assembly behavior on NC should investigated because photophysical properties are influenced by assembly conditions. However,...

Careful molecular engineering has enabled solution processing of well-performing bulk-heterojunction photovoltaic layers comprising insoluble materials.

Postsynthesis anion-exchange reaction of cesium lead halide (CsPbX3; X = Cl, Br, and I) perovskite nanocrystals (NCs) has emerged as a unique strategy to control band gap. Recently, the partially anion-exchanged CsPb(Br/I)3 NC was reported form an inhomogeneously alloyed heterostructure, which could possibly some emission sites depending on composition in single NC. In this work, we observed situ behavior NCs during reaction. Photon-correlation measurements revealed that mixed exhibited...

Precise control of assembled structures quantum dots (QDs) is crucial for realizing the desired photophysical properties, but this remains challenging. Especially, one‐dimensional (1D) rare due to nearly isotropic nature QDs. Herein, we propose a novel strategy controlling 1D‐arrangement range cubic perovskite QDs in solution based on morphological modification supramolecular polymer (SP) template. The original template with short and tangled fibrous structure prepared low‐polarity solvent...

Precise control of assembled structures quantum dots (QDs) is crucial for realizing the desired photophysical properties, but this remains challenging. Especially, one‐dimensional (1D) rare due to nearly isotropic nature QDs. Herein, we propose a novel strategy controlling 1D‐arrangement range cubic perovskite QDs in solution based on morphological modification supramolecular polymer (SP) template. The original template with short and tangled fibrous structure prepared low‐polarity solvent...

Abstract A high‐order heterogeneous nanostructure (heterostructure) composed of semiconductor nanocrystals (NCs) and organic dye supramolecular aggregates can exhibit distinctive photophysical properties arising from the interaction between them activate multicomponent materials chemistry. Herein, study demonstrates a hierarchical coaggregation pathway guiding heterostructure cubic‐shaped perovskite NC perylene bisimide derivative (PBI) aggregates. The final morphologies in their are...

Investigation of the energy transfer (ET) between perovskite nanocrystals (PNCs) and organic dyes is crucial because PNCs are suitable donor materials for creating photosensitizer systems. In this study, we investigated relationship a singlet ET mechanism spectral overlap using CsPbBr3 PNC-cyanine dyes─Cy3 Cy5. We prepared PNC-dye linkage systems at single-PNC levels. The results our study reveal that efficient occurs via fluorescence resonance (FRET) in PNC-Cy3 system. Even PNC-Cy5 system,...

Laser manipulation and laser trapping techniques were applied to μm sized gel-like wire-type dendrimer (L3PPE130 L4PPE8) assemblies, which are formed at drying process of their tetrahydrofuran (THF) solution on a glass substrate. Deformation extension single assemblies demonstrated with irradiation focused 1064 nm beam by scanning microscope stage. In repetitive experiments, contraction swelling the assembly observed in response switch off beam, respectively, case L3PPE130 assembly,...

Abstract Photoinduced electron transfer (ET) processes in a donor–acceptor system based on triphenylamine and perylene imide have been studied at the single‐molecule (SM) ensemble levels. The exists as two isomers, one of which undergoes forward reverse ET toluene with decay constants 3.0 2.2 × 10 9 s −1 , respectively, resulting dual emission quenched delayed fluorescence while other isomer remains ET‐inactive. both isomers is heavily more polar solvent, diethyl ether, by ET. A broad range...