Proton-Transfer Mechanism for Dispersed Decay Kinetics of Single Molecules Isolated in Potassium Hydrogen Phthalate

Bott, Eric D.; Riley, Erin A.; Kahr, Bart; Reid, Philip J.

doi:10.1021/nn900596a

Cited by 18 publications

(33 citation statements)

References 70 publications

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“…149 This analysis clearly suggests that the intrinsic physical mechanism is not originated from a single Poisson event under an exponential rate dynamics, which reflects that the interfacial ET involves complex rate process that cannot be defined by a static rate constant. Analogous power-law statistics for both the on and This journal is c The Royal Society of Chemistry 2010 off periods have been extensively investigated in fluorescence blinking dynamics of organic dyes, 40,41,[150][151][152] semiconductor QDs, 149,153 and other single emitters. 154 …”

Section: Electron Transfer Between Organic Dyes and Tiomentioning

confidence: 99%

Single-molecule, single-particle fluorescence imaging of TiO2-based photocatalytic reactions

2010

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Nanostructured metal oxide semiconductors, such as TiO(2) and ZnO, have attracted great attention as the promising material for photovoltaic devices, photocatalysts for water splitting and environmental purification, sensors, batteries, etc. In this critical review, we have focused on the on-site observation of interfacial chemical reactions involving charge carriers and reactive oxygen species (ROS), such as singlet oxygen and the hydroxyl radical, generated by the photoexcitation of TiO(2) nanoparticles using single-molecule, single-particle fluorescence spectroscopy. Advanced fluorescence imaging techniques enable us to determine the location of the photocatalytically active sites that are closely related to the defects heterogeneously distributed on the surface. Consequently, this review provides a great opportunity to understand the temporal and spatial heterogeneities within an individual catalyst particle, allowing for the potential use of single-molecule, single-particle approaches in the analysis of photocatalytic reactions (189 references).

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Section: Electron Transfer Between Organic Dyes and Tiomentioning

confidence: 99%

Single-molecule, single-particle fluorescence imaging of TiO2-based photocatalytic reactions

2010

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“…[8][9][10][11] To aid in the interpretation of the data, Monte Carlo simulations have been utilized to model fluorescence time trajectories that are affected by these processes. [12][13][14][15] In particular, we seek to further refine the model and to determine the accuracy of the single molecule analysis used in experimental data processing. Through both experimental and computational approaches, we aim to better understand the requirements for molecular structure and local environment that enable stable organic (opto)electronic devices less susceptible to photodegradation.…”

Section: -S R= Nodipsmentioning

confidence: 99%

“…Previous research has modeled the charge carrier dynamics as observed in single-molecule fluorescence experiments by using a three-level system, with a ground state, excited state and dark state. [12][13][14][15] Our previous work has used a four-level system, which includes the states mentioned above and, additionally, an irreversible "photobleached" state, as well as a non-radiative recombination rate (k 21n ) between the excited state and the ground state (Fig. 4).…”

Section: Photodegradation and Recovery In Filmsmentioning

confidence: 99%

Effect of molecular side groups and local nanoenvironment on photodegradation and its reversibility

Quist

Tollefsen

et al. 2018

Organic Photonic Materials and Devices XX

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Right click to open a feedback form in a new tab to let us know how this document benefits you. Effect of molecular side groups and local nanoenvironment on photodegradation and its reversibility,"ABSTRACT Degradation of organic semiconductors in the presence of oxygen is one of the bottlenecks preventing their wide-spread use in optoelectronic devices. The first step towards such degradation in functionalized pentacene (Pn) derivatives is formation of endoperoxide (EPO), which can either revert back to the parent molecule or proceed to molecule decomposition. We present the study of reversibility of EPO formation through probing the photophysical properties of functionalized fluorinated pentacene (Pn-R-F8) derivatives. Experiments are done in solutions and in films both at the single molecule level and in the bulk. In solutions, degradation of optical absorption and its partial recovery after thermolysis were quantified for various derivatives depending on the solvent. At the single molecule level, low concentrations of each type of molecules were imaged in a variety of polymer matrices at 633 nm excitation at room temperature in air using wide-field fluorescence microscopy. Fluorescence time trajectories were collected and statistically analyzed to quantify blinking due to reversible EPO formation depending on the host matrix. To understand the physical changes of the molecular system, a Monte Carlo method was used to create a multi-level simulation, which enabled us to relate the change in the molecular transition rates to the experimentally measured parameters. At the bulk level, photoluminescence decay due to photobleaching and recovery due to EPO reconversion were measured for the same derivatives incorporated into various matrices. These studies provide insight into the synergistic effect of the local nanoenvironment and molecular side groups on the oxygen-related degradation and subsequent recovery which is important for development of organic electronic devices.

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“…Previous studies have used a three level system, with a ground state, excited state and dark state, to model the charge carrier kinetics as observed in single-molecule fluorescence experiments. [11][12][13][14] In order to fully utilize our experimental findings and separate blinking events from photobleaching, we added a fourth, irreversible dark state which simulates photobleaching. Also guided by our experimental data, which show similarity of "on" times CCDFs for "blinkers" and "non-blinkers", is our choice of a common intermediate level (denoted as "dark states" in Fig.3) for "blinkers" and "non-blinkers", from which the molecule can either return to the ground state to be re-excited (for "blinker") or is permanently photobleached (for "non-blinker").…”

Section: Monte Carlo Simulation 31 the Modelmentioning

confidence: 99%

“…In order to gain physical insight into the dynamics of the nanoscale interactions, Monte Carlo simulations have been utilized to model the charge carrier transitions that determine the experimentally measured fluorescence time trajectories. [11][12][13][14] In the present study, we use a modified Monte Carlo model to provide insight into photophysics of individual Pn-TCHS-F8 molecules, depending on their nanoscale environment. Understanding these interactions provides insight on the formation of bulk heterojunctions (BHJs), which are the basis for most successful organic solar cells and other organic optoelectronic devices.…”

Section: Introductionmentioning

confidence: 99%

Single molecule-level study of donor-acceptor interactions and nanoscale environment in blends

et al. 2017

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Organic semiconductors have attracted considerable attention due to their applications in low-cost (opto)electronic devices. The most successful organic materials for applications that rely on charge carrier generation, such as solar cells, utilize blends of several types of molecules. In blends, the local environment strongly influences exciton and charge carrier dynamics. However, relationship between nanoscale features and photophysics is difficult to establish due to the lack of necessary spatial resolution. We use functionalized fluorinated pentacene (Pn) molecule as single molecule probes of intermolecular interactions and of the nanoscale environment in blends containing donor and acceptor molecules. Single Pn donor (D) molecules were imaged in PMMA in the presence of acceptor (A) molecules using wide-field fluorescence microscopy. Two sample configurations were realized: (i) a fixed concentration of Pn donor molecules, with increasing concentration of acceptor molecules (functionalized indenofluorene or PCBM) and (ii) a fixed concentration of acceptor molecules with an increased concentration of the Pn donor. The D-A energy transfer and changes in the donor emission due to those in the acceptor-modified polymer morphology were quantified. The increase in the acceptor concentration was accompanied by enhanced photobleaching and blinking of the Pn donor molecules. To better understand the underlying physics of these processes, we modeled photoexcited electron dynamics using Monte Carlo simulations. The simulated blinking dynamics were then compared to our experimental data, and the changes in the transition rates were related to the changes in the nanoscale environment. Our study provides insight into evolution of nanoscale environment during the formation of bulk heterojunctions.

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Proton-Transfer Mechanism for Dispersed Decay Kinetics of Single Molecules Isolated in Potassium Hydrogen Phthalate

Cited by 18 publications

References 70 publications

Single-molecule, single-particle fluorescence imaging of TiO2-based photocatalytic reactions

Single-molecule, single-particle fluorescence imaging of TiO2-based photocatalytic reactions

Effect of molecular side groups and local nanoenvironment on photodegradation and its reversibility

Single molecule-level study of donor-acceptor interactions and nanoscale environment in blends

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