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Chemistry

University of Kentucky

Chemistry Faculty Publications

Series

Organic semiconductors

Articles 1 - 7 of 7

Full-Text Articles in Physical Sciences and Mathematics

Micro-Raman Imaging Of Isomeric Segregation In Small-Molecule Organic Semiconductors, Chiung-Wei Huang, Xiao You, Peter J. Diemer, Anthony Joseph Petty Ii, John E. Anthony, Oana D. Jurchescu, Joanna M. Atkin Feb 2019

Micro-Raman Imaging Of Isomeric Segregation In Small-Molecule Organic Semiconductors, Chiung-Wei Huang, Xiao You, Peter J. Diemer, Anthony Joseph Petty Ii, John E. Anthony, Oana D. Jurchescu, Joanna M. Atkin

Chemistry Faculty Publications

Charge transport in organic semiconductors is highly sensitive to film heterogeneity and intermolecular interactions, but probing these properties on the length scales of disorder is often difficult. Here we use micro-Raman spectroscopy to assign vibrational modes of isomerically pure syn and anti 2,8-difluoro-5,11-bis(triethylsilylethynyl)anthradithiophene (diF-TES ADT) by comparing to density functional theory calculations. With polarization-dependent measurements, we determine the orientation of crystallites in pure isomers. In mixed-isomer samples, we observe narrow linewidths and superposition spectra, indicating coexistence of isomerically pure sub-domains on length scales smaller than the probe area. Using the ring breathing modes close to 1300 cm−1 as indicators …


Effect Of Molecular Side Groups And Local Nanoenvironment On Photodegradation And Its Reversibility, Nicole Quist, Mark Li, Ryan Tollefsen, Michael Haley, John Anthony, Oksana Ostroverkhova Feb 2018

Effect Of Molecular Side Groups And Local Nanoenvironment On Photodegradation And Its Reversibility, Nicole Quist, Mark Li, Ryan Tollefsen, Michael Haley, John Anthony, Oksana Ostroverkhova

Chemistry Faculty Publications

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 …


Single Molecule-Level Study Of Donor-Acceptor Interactions And Nanoscale Environment In Blends, Nicole Quist, Rebecca Grollman, Jeremy Rath, Alex Robertson, Michael Haley, John E. Anthony, Oksana Ostroverkhova Feb 2017

Single Molecule-Level Study Of Donor-Acceptor Interactions And Nanoscale Environment In Blends, Nicole Quist, Rebecca Grollman, Jeremy Rath, Alex Robertson, Michael Haley, John E. Anthony, Oksana Ostroverkhova

Chemistry Faculty Publications

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 …


Quantitative Analysis Of The Density Of Trap States At The Semiconductor-Dielectric Interface In Organic Field-Effect Transistors, Peter J. Diemer, Zachary A. Lamport, Yaochuan Mei, Jeremy W. Ward, Katelyn P. Goetz, Wei Li, Marcia M. Payne, Martin Guthold, John E. Anthony, Oana D. Jurchescu Sep 2015

Quantitative Analysis Of The Density Of Trap States At The Semiconductor-Dielectric Interface In Organic Field-Effect Transistors, Peter J. Diemer, Zachary A. Lamport, Yaochuan Mei, Jeremy W. Ward, Katelyn P. Goetz, Wei Li, Marcia M. Payne, Martin Guthold, John E. Anthony, Oana D. Jurchescu

Chemistry Faculty Publications

The electrical properties of organic field-effect transistors are governed by the quality of the constituting layers, and the resulting interfaces. We compare the properties of the same organic semiconductor film, 2,8-difluoro- 5,11-bis (triethylsilylethynyl) anthradithiophene, with bottom SiO2 dielectric and top Cytop dielectric and find a 10× increase in charge carrier mobility, from 0.17 ± 0.19 cm2 V−1 s−1 to 1.5 ± 0.70 cm2 V−1 s−1, when the polymer dielectric is used. This results from a significant reduction of the trap density of states in the semiconductor band-gap, and a decrease in the …


Photophysics Of Organic Semiconductors: From Ensemble To The Single-Molecule Level, Rebecca Grollman, Whitney E. B. Shepherd, Alexander Robertson, Keshab R. Paudel, John E. Anthony, Oksana Ostroverkhova Mar 2015

Photophysics Of Organic Semiconductors: From Ensemble To The Single-Molecule Level, Rebecca Grollman, Whitney E. B. Shepherd, Alexander Robertson, Keshab R. Paudel, John E. Anthony, Oksana Ostroverkhova

Chemistry Faculty Publications

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 wide- field 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, …


Low-Temperature Phase Transitions In A Soluble Oligoacene And Their Effect On Device Performance And Stability, J. W. Ward, K. P. Goetz, A. Obaid, Marcia M. Payne, P. J. Diemer, C. S. Day, John E. Anthony, O. D. Jurchescu Aug 2014

Low-Temperature Phase Transitions In A Soluble Oligoacene And Their Effect On Device Performance And Stability, J. W. Ward, K. P. Goetz, A. Obaid, Marcia M. Payne, P. J. Diemer, C. S. Day, John E. Anthony, O. D. Jurchescu

Chemistry Faculty Publications

The use of organic semiconductors in high-performance organic field-effect transistors requires a thorough understanding of the effects that processing conditions, thermal, and bias-stress history have on device operation. Here, we evaluate the temperature dependence of the electrical properties of transistors fabricated with 2,8-difluoro-5,11-bis(triethylsilylethynyl)anthradithiophene, a material that has attracted much attention recently due to its exceptional electrical properties. We have discovered a phase transition at T = 205 K and discuss its implications on device performance and stability. We examined the impact of this low-temperature phase transition on the thermodynamic, electrical, and structural properties of both single crystals and thin films …


Topography-Guided Spreading And Drying Of 6,13-Bis(Triisopropylsilylethynyl)-Pentacene Solution On A Polymer Insulator For The Field-Effect Mobility Enhancement, Chang-Min Keum, Jin-Hyuk Bae, Min-Hoi Kim, Hea-Lim Park, Marcia M. Payne, John E. Anthony, Sin-Doo Lee May 2013

Topography-Guided Spreading And Drying Of 6,13-Bis(Triisopropylsilylethynyl)-Pentacene Solution On A Polymer Insulator For The Field-Effect Mobility Enhancement, Chang-Min Keum, Jin-Hyuk Bae, Min-Hoi Kim, Hea-Lim Park, Marcia M. Payne, John E. Anthony, Sin-Doo Lee

Chemistry Faculty Publications

We report on the enhancement of the field-effect mobility of solution-processed 6,13-bis(triisopropylsilylethynyl)-pentacene (TIPS-pentacene) by unidirectional topography (UT) of an inkjet-printed polymer insulator. The UT leads to anisotropic spreading and drying of the TIPS-pentacene droplet and enables to spontaneously develop the ordered structures during the solvent evaporation. The mobility of the UT-dictated TIPS-pentacene film (0.202 ± 0.012 cm2/Vs) is found to increase by more than a factor of two compared to that of the isotropic case (0.090 ± 0.032 cm2/Vs). The structural arrangement of the TIPS-pentacene molecules in relation to the mobility enhancement is described within an …