Single-molecule imaging of organic semiconductors: Toward nanoscale insights into photophysics and molecular packing

Shepherd, Whitney E. B.; Grollman, Rebecca R.; Robertson, Alexander; Paudel, Keshab Raj; Hallani, Rawad K.; Loth, Marsha A.; Anthony, John E.; Ostroverkhova, Oksana

doi:10.1016/j.cplett.2015.04.014

Cited by 16 publications

(35 citation statements)

References 48 publications

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“…The optical absorption of the t-bu BTBTB derivative, as well as of PMMA, PVK, and PS, is in the UV region, 22 which enables their utility as non-fluorescent hosts for SM imaging at 532 nm and 633 nm. The t-bu BTBTB derivative forms spin-cast polycrystalline films with a dominant (01-1)crystallite orientation 23 and exhibits photoconductivity under UV excitation.…”

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confidence: 99%

Photophysics of organic semiconductors: from ensemble to the single-molecule level

et al. 2015

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We present photophysical properties of functionalized anthradithiophene (ADT) and pentacene (Pn) derivatives, as well as charge and energy transfer properties of donor-acceptor (D/A) pairs of these derivatives. All molecules studied were fluorescent and photostable enough to be imaged on the single-molecule level in a variety of polymeric and in a functionalized benzothiophene (BTBTB) crystalline host using room-temperature widefield epifluorescence microscopy. Flexibility of functionalization of both guest (ADT, Pn) and host (BTBTB or polymer) molecules can be used for systematic studies of nanoscale morphology and photophysics of D/A organic semiconductor bulk heterojunctions, as well as in applications relying on FRET, using single-molecule fluorescence microscopy.

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confidence: 99%

Photophysics of organic semiconductors: from ensemble to the single-molecule level

et al. 2015

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“…Single molecule fluorescence spectroscopy was performed under a 633 nm excitation, using a 100x objective and Olympus IX-71 inverted microscope, in the wide-field geometry with an EMCCD detector, as described in detail in our previous publications. 3,4 3. RESULTS AND DISCUSSION how the polarity of the solvent affects the rate of the degradation.…”

Section: Measurements Of Optical Absorption and Photoluminescencementioning

confidence: 99%

“…2,3 However, EPO formation rate is environment dependent, and can be manipulated with the change in the film composition. 3 To better understand which environmental changes are most effective in inhibiting EPO formation and in prolonging the lifetime of devices, we study these changes on both the nanoscale with single molecule spectroscopy 3,4 and on the semi-bulk scale with absorption and photoluminescence (PL) measurements of dilute solutions and films containing low concentrations of molecules of interest incorporated into polymer matrices. 5,6 Our studies probe the photophysics of technologically relevant solution-processable high-mobility functionalized acene derivatives which have been previously utilized in thin-film-transistors and other (opto)electronic applications.…”

Section: Introductionmentioning

confidence: 99%

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

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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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“…The MATLAB scripts located the fluorophores and created the fluorescence time trace for each fluorophore as detailed in our previous work. 15 The time traces were analyzed, and fluorophores that exhibited only one "on"-"off" event ("non-blinkers") and multiple events ("blinkers") were separated.…”

Section: Single Molecule Spectroscopymentioning

confidence: 99%

“…For example, the fluorescence quantum yield (QY) for this derivative in PMMA is 0.82. 15 This is the ratio of the number of photons emitted compared to the number of photons absorbed. In our model, only the transition between the excited state and the ground state radiates, and therefore the QY in a given time frame (dt) can be defined as follows: .…”

Section: Monte Carlo Simulation 31 the Modelmentioning

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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Single-molecule imaging of organic semiconductors: Toward nanoscale insights into photophysics and molecular packing

Cited by 16 publications

References 48 publications

Photophysics of organic semiconductors: from ensemble to the single-molecule level

Photophysics of organic semiconductors: from ensemble to the single-molecule level

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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