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| Creator | Title | Description | Subject | Date | ||
|---|---|---|---|---|---|---|
| 1 |
 | Vardeny, Zeev Valentine | Absorption studies of charged excitations in α-sexithiophene | We present photoexcitation studies of vacuum deposited neutral films of α,ω-substituted sexithiophene (α-6T) using photoinduced absorption (PA) and PAdetected magnetic resonance spectroscopy (PADMR). We find evidence for photoinduced polarons having spin 1/2, with two absorption bands at 0.80... | alpha- sexithiophene; Charged excitations; Photoexcitation; Photoinduced absorption | 1996 |
| 2 |
 | Vardeny, Zeev Valentine | Excitation dynamics in single molecular crystals of α-hexathiophene from femtosecond to millisecond | We identify odd- and even-parity states and measure transient photomodulation spectra of Frenkel excitons in a-hexathiophene single crystals. The lowest Frenkel excitons are characterized by a stimulated emission band at ~2 eV and an absorption band at 1.3 eV. Intramolecular internal conversion go... | Excitation dynamics; alpha-hexathiophene; Frenkel excitons; pi-conjugated polymers; Photoexcitation | 2001-04 |
| 3 |
 | Vardeny, Zeev Valentine | Experimental determination of the charge/neutral branching ratio η in the photoexcitation of ∏-conjugated polymers by broadband ultrafast spectroscopy | We demonstrate a long-sought reliable method for determining the important branching ratio η between photogenerated charged polarons and neutral excitons in ∏-conjugated polymer films and solutions, using femtosecond transient photomodulation spectroscopy with broad spectral range from 0.14 to ... | pi-conjugated polymers; Charge/neutral branching ratio; Photoexcitation; nu value; Broadband ultrafast spectroscopy | 2007-02 |
| 4 |
 | Vardeny, Zeev Valentine | Optical probes of excited states in poly (p-phenylenevinylene) | We have studied electronic excited states in films of poly(p-phenylenevinylene) using picosecond transient and cw photomodulation, photoluminescence, and their excitation spectra, as well as electroabsorption spectroscopy. We have determined all the important energy levels of singlet excitons with... | Poly (p-phenylenevinylene); Photoexcitation | 1994-01 |
| 5 |
 | Vardeny, Zeev Valentine | Photogenerated gap states in polyacetylene | We have measured the optical absorption spectrum of photogenerated gap states in polyacetylene, (CH)X . From a comparison with electroabsorption spectra the charge state of the excitations is determined. In both isomers of (CH)X locally neutral (exciton-like) states are observed. In addition a charg... | Gap state; Photoexcitation | 1983-06 |
| 6 |
 | Vardeny, Zeev Valentine; Ehrenfreund, Eitan A. | Photogeneration of confined soliton pairs (bipolarons) in polythiophene | From photoinduced absorption and light-induced electron-spin resonance, we demonstrate that the dominant photocarriers generated in polythiophene with excitation above the energy gap (Eg) are charged bipolarons (spin 0). The observation of bipolarons (B2± ) rather than polarons (Pf ) as the dominan... | Photoinduced absorption; Photocarriers; Bipolarons; Photoexcitation | 1986-02 |
| 7 |
 | Vardeny, Zeev Valentine | Photoinduced infrared activity in polyacetylene | Photoexcitation of trans - but not cis -polyacetylene, results in the appearance of strongly-ir-active local modes at 1370 and 1260 cm-1. This observation demonstrates that the photogeneration of self-localized charge carriers is unique to the trans isomer. In spite of their localization the kineti... | Photoinduced infrared activity; Photoexcitation | 1983-06 |
| 8 |
 | Vardeny, Zeev Valentine | Spin and spectral signatures of polaron pairs in ∏-conjugated polymers | We have studied polaron pair photoexcitations in a variety of p-conjugated polymer films by photoinduced absorption (PA) and optically detected magnetic resonance (ODMR). Both luminescent and nonluminescent polymers have been studied. An exchange interaction between polarons broadens their magneti... | Spin signatures; spectral signatures; Photoinduced absorption; Photoexcitation | 1997-08 |
| 9 |
 | Vardeny, Zeev Valentine | Studies of charged excitations in ∏-conjugated oligomers and polymers by optical modulation | We have studied photogenerated charged excitations in sexithiophene and a variety of p-conjugated polymers by photoinduced absorption (PA) and PA-detected magnetic resonance. We found distinct spin signatures for polarons and bipolarons, which enabled us to separate their contributions to the PA spe... | Pi-conjugated oligomers; Pi-conjugated polymers; Charged excitations; Optical modulation; Spin signatures; Bipolarons; Photoexcitation | 1996-08 |
| 10 |
 | Vardeny, Zeev Valentine | Studies of photoexcited states in polyacetylene and poly(parpahenylenevinylene) by absorption detected magnetic resonance: the case of neutral photoexcitations | Photoexcited states in trans polyacetylene [f-(CH).x ] and in alkoxy derivatives of poly(paraphenylenevinylene) (PPV) have been studied by the technique of absorption detected magnetic resonance. In addition to the stable charged photoexcitations, which are charged solitons in f-(CH).x and bipolaro... | Poly(parpahenylenevinylene); Photoexcitation | 1992-02 |
| 11 |
 | Vardeny, Zeev Valentine | Ultrafast dynamics of excitons and solitons in disubstituted polyacetylene | We studied the ultrafast photoexcitation dynamics in disubstituted polyacetylene (DPA). We found two distinctively different relaxation channels for the photogenerated excitons; ionic and covalent pathways. In DPA films the photogenerated odd-parity (Bu) excitons that are responsible for the high ... | Ultrafast dynamics; Photoexcitation; Excitons; Disubstituted polyacetylene; Excitons; DPA; Relaxation channels | 2003-01 |
| 12 |
 | Vardeny, Zeev Valentine | Universal properties of quasi-one-dimensional excitons in semiconducting single-walled carbon nanotubes and ∏-conjugated polymers | The nature of the primary photoexcitations in semiconducting single-walled carbon nanotubes (S-SWCNTs) is of strong current interest. We have studied the emission spectra of S-SWCNTs and two different rr-conjugated polymers in solutions and films, and have also performed ultrafast pump-probe spectr... | Carbon nanotubes; pi-conjugated polymers; SWCNT; Photoexcitation; Optoelectronic properties; Quasi-one-dimensional | 2006 |
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