Browsing by Author "Hayes, Sophia C."

Article

Analysis of depolarization ratios of ClNO2 dissolved in methanol

Trimithioti, Marilena; Akimov, A. V.; Prezhdo, O. V.; Hayes, Sophia C. (2014)

A detailed analysis of the resonance Raman depolarization ratio dispersion curve for the N-O symmetric stretch of nitryl chloride in methanol at excitation wavelengths spanning the D absorption band is presented. The ...

Article

Analysis of the excited-state absorption spectral bandshape of oligofluorenes

Hayes, Sophia C.; Silva, C. (2010)

We present ultrafast transient absorption spectra of two oligofluorene derivatives in dilute solution. These spectra display a photoinduced absorption band with clear vibronic structure, which we analyze rigorously using ...

Article

Charge generation in inorganic/organic photovoltaic blends

Westenhoff, S.; Hayes, Sophia C.; Greenham, N. C.; Silva, C. (2004)

We apply ultrafast spectroscopy to investigate charge generation kinetics in blends of semiconducting polymers and cadmium selenide nanocrystals with photovoltaic applications. The rate is limited by diffusion of the primary ...

Book Chapter

Charge Transfer Excitons in Supramolecular Semiconductor Nanostructures

Glowe, J. -F; Perrin, M.; Beljonne, D.; Karsenti, L.; Hayes, Sophia C.; Gardebien, F.; Silva, C. (wiley, 2010)

Article

Charge-transfer excitons in strongly coupled organic semiconductors

Glowe, J. -F; Perrin, M.; Beljonne, D.; Hayes, Sophia C.; Gardebien, F.; Silva, C. (2010)

Time-resolved and temperature-dependent photoluminescence measurements on one-dimensional sexithiophene lattices reveal intrinsic branching of photoexcitations to two distinct species: self-trapped excitons and dark ...

Article

Correlating the effective work function at buried organic/metal interfaces with organic solar cell characteristics

Shamieh, Basel; Anselmo, Ana S.; Vogel, Uwe; Lariou, Eirini; Hayes, Sophia C.; Koch, Norbert; Frey, Gitti L. (2018)

The energy level alignment at organic semiconductor/metal interfaces determines the efficiency of charge injection and collection in organic electronic devices. Back electrodes, applied after the organic layer is processed, ...

Article

Direct observation of ultrafast long-range charge separation at polymer-fullerene heterojunctions

Provencher, F.; Bérubé, N.; Parker, A. W.; Greetham, G. M.; Towrie, M.; Hellmann, C.; Côté, M.; Stingelin, N.; Silva, C.; Hayes, Sophia C. (2014)

In polymeric semiconductors, charge carriers are polarons, which means that the excess charge deforms the molecular structure of the polymer chain that hosts it. This results in distinctive signatures in the vibrational ...

Conference Object

Effect of molecular weight on the vibronic structure of a diketopyrrolopyrrole polymer

Hayes, Sophia C.; Pieridou, Galatia K.; Vezie, M.; Few, S.; Bronstein, H.; Meager, I.; McCulloch, I.; Nelson, J. (SPIE, 2016)

Resonance Raman Spectroscopy (RRS) is employed in this study to examine the influence of molecular weight on the optical response of a diketopyrrolopyrrole polymer (DPP-TT-T) in solution. The vibronic structure observed ...

Article

Emission from the stable Blatter radical

Karecla, G.; Papagiorgis, Panagiotis; Panagi, N.; Zissimou, Georgia A.; Constantinides, Christos P.; Koutentis, Panayiotis Andreas; Itskos, Grigorios; Hayes, Sophia C. (2017)

1,3-Diaryl-1,4-dihydro-1,2,4-benzotriazin-4-yls are air stable organic radicals which have been exploited for their interesting magnetic properties. Herein, we present the optical properties of the "parent" radical namely ...

Article

Emission from the stable Blatter radicalAAA

Karecla, G.; Papagiorgis, Panagiotis; Panagi, N.; Zissimou, Georgia A.; Constantinides, Christos P.; Koutentis, Panayiotis Andreas; Itskos, Grigorios; Hayes, Sophia C. (2017)

1,3-Diaryl-1,4-dihydro-1,2,4-benzotriazin-4-yls are air stable organic radicals which have been exploited for their interesting magnetic properties. Herein, we present the optical properties of the "parent" radical namely ...

Article

Erratum: Tetraphenylhexaazaanthracenes: 16π Weakly Antiaromatic Species with Singlet Ground States (Org. Lett. (2015) 17 (4026-4029) DOI: 10.1021/acs.orglett.5b01923)

Constantinides, Christos P.; Zissimou, Georgia A.; Berezin, Andrey A.; Ioannou, Theodosia A.; Manoli, Maria; Tsokkou, Demetra; Theodorou, E.; Hayes, Sophia C.; Koutentis, Panayiotis Andreas (2016)

Article

Erratum: UV resonance Raman study of TTR(105-115) structural evolution as a function of temperature (Journal of Physical Chemistry B (2011) 115 (4088-4098) DOI: 10.1021/jp107519b)

Pieridou, Galatia K.; Avgousti-Menelaou, C.; Tamamis, Phanourios; Archontis, Georgios Z.; Hayes, Sophia C. (2011)

Article

Erratum: UV resonance Raman study of TTR(105-115) structural evolution as a function of temperature (Journal of Physical Chemistry B (2011) 115 (4088-4098) DOI: 10.1021/jp107519b)AAA

Pieridou, Galatia K.; Avgousti-Menelaou, C.; Tamamis, Phanourios; Archontis, Georgios Z.; Hayes, Sophia C. (2011)

Article

Exploring the origin of high optical absorption in conjugated polymers

Vezie, M. S.; Few, S.; Meager, I.; Pieridou, Galatia K.; Dörling, B.; Ashraf, R. S.; Goñi, A. R.; Bronstein, H.; McCulloch, I.; Hayes, Sophia C.; Campoy-Quiles, M.; Nelson, J. (2016)

The specific optical absorption of an organic semiconductor is critical to the performance of organic optoelectronic devices. For example, higher light-harvesting efficiency can lead to higher photocurrent in solar cells ...

Article

Femtosecond pump-probe studies of chlorine dioxide photochemistry in water and acetonitrile

Philpott, M. J.; Hayes, Sophia C.; Reid, P. J. (1998)

The reaction dynamics of chlorine dioxide (OClO) dissolved in water and acetonitrile are investigated using femtosecond pump-probe spectroscopy. The change in optical density following photoexcitation of OClO at 400 nm is ...

Article

Femtosecond UV pump/near-IR probe studies of the solvent-dependent excited-state decay dynamics of chlorine dioxide

Hayes, Sophia C.; Cooksey, C. C.; Wallace, P. M.; Reid, P. J. (2001)

The excited-state decay and geminate-recombination dynamics of chlorine dioxide (OClO) are investigated using UV pump/near-IR probe spectroscopy. Experiments are performed with 200-fs time resolution on OClO dissolved in ...

Article

The formation of ClOO following the photoexcitation of aqueous OClO studied by two-color, time-resolved resonance Raman spectroscopy

Thomsen, C. L.; Philpott, M. P.; Hayes, Sophia C.; Reid, P. J. (2000)

The photochemistry of chlorine dioxide (OClO) is investigated by two-color time-resolved resonance Raman spectroscopy. Pump and probe wavelengths of 390 and 260 nm, respectively, are used to monitor photoproduct formation ...

Article

Geminate recombination and vibrational relaxation dynamics of aqueous chlorine dioxide: A time-resolved resonance Raman study

Hayes, Sophia C.; Philpott, M. J.; Reid, P. J. (1998)

The photochemical dynamics of aqueous chlorine dioxide (OClO) are investigated using time-resolved resonance Raman spectroscopy. Stokes and anti-Stokes spectra are measured as a function of time following photoexcitation ...

Article

Impact of Structural Polymorphs on Charge Collection and Nongeminate Recombination in Organic Photovoltaic Devices

Keivanidis, Panagiotis E.; Khan, Jafar I.; Katzenmeier, Leon; Kan, Zhipeng; Limbu, Saurav; Constantinou, Marios; Lariou, Eirini; Constantinides, Georgios; Hayes, Sophia C.; Kim, Ji-Seon; Laquai, Frédéric (2018)

The formation of different types of structural polymorphs of poly(3-hexyl-thiophene) (P3HT) affects the performance of organic photovoltaic (OPV) devices that use thermally annealed P3HT:PCBM[60] blend films as a photoactive ...

Article

The Importance of Microstructure in Determining Polaron Generation Yield in Poly(9,9-dioctylfluorene)

Cheetham, Nathan J.; Ortiz, Manuel; Perevedentsev, Aleksandr; Dion-Bertrand, Laura-Isabelle; Greetham, Gregory M.; Sazanovich, Igor V.; Towrie, Michael; Parker, Anthony W.; Nelson, Jenny; Silva, Carlos; Bradley, Donal D. C.; Hayes, Sophia C.; Stavrinou, Paul N. (2019)

Understanding the structure–property relationships that govern exciton dissociation into polarons in conjugated polymers is key in developing materials for optoelectronic applications such as light-emitting diodes and solar ...