Triplet Energies of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi mathvariant="italic">π</mml:mi></mml:math>-Conjugated Polymers

Monkman, Andrew P.; Hartwell, L. J.; Horsburgh, L. E.; Hamblett, I.; Navaratnam, S.

doi:10.1103/physrevlett.86.1358

Cited by 264 publications

(229 citation statements)

References 29 publications

(32 reference statements)

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“…24,27 ), where T 1 − T n splitting is about 1.4-2 eV. Our calculations predict T 1 − T n splitting for (7,6) tube to be about 0.5-0.6 eV (see table I).…”

Section: (Top)mentioning

confidence: 52%

“…Subsequently, the energetic separation between S 1 and S n state has been used as a lower bound estimate of the S 1 excitonic binding energy in Spectroscopic study of triplet states in materials with small spin-orbit coupling is a challenge for experiment. Yet, the triplet energies has been measured in a broad range of different π-conjugated polymers 27 . This task remains a problem for CNTs.…”

Section: (Top)mentioning

confidence: 99%

“…2 (top). Reference PPV compound is one of the most explored and understood luminescent polymer 27 , and (7,6) 31 . We use B3LYP and PBE1PBE hybrid functionals, containing 20% and 25% of the orbital exchange, respectively.…”

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confidence: 99%

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Triplet State Absorption in Carbon Nanotubes: A TD−DFT Study

Tretiak

2007

Nano Lett.

116

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We predict properties of triplet excited states in single-walled carbon nanotubes (CNTs) using a time-dependent density-functional theory (TD-DFT). We show that the lowest triplet state energy in CNTs to be about 0.2-0.3 eV lower than the lowest singlet states. Like in π-conjugated polymers, the lowest CNT triplets are spatially localized. These states show strong optical absorption at about 0.5-0.6 eV to the higher lying delocalized triplet states. These results demonstrate striking similarity of the electronic features between CNTs and π-conjugated polymers and provide explicit guidelines for spectroscopic detection of CNT triplet states.

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“…24,27 ), where T 1 − T n splitting is about 1.4-2 eV. Our calculations predict T 1 − T n splitting for (7,6) tube to be about 0.5-0.6 eV (see table I).…”

Section: (Top)mentioning

confidence: 52%

Section: (Top)mentioning

confidence: 99%

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Triplet State Absorption in Carbon Nanotubes: A TD−DFT Study

Tretiak

2007

Nano Lett.

116

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“…12,13 Attempts to observe phosphorescence have proved unsuccessful, 11,12 although some information has been inferred from data on heavy metal quinolates. 11 We have shown 14 that pulse radiolysis of benzene solutions selectively produces triplet states of conjugated organic polymers by energy transfer from appropriate sensitizers following pulse radiolysis of benzene solutions. The triplet state of Alq 3 is characterized in the same way.…”

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confidence: 99%

“…20 Energy transfer is a valuable method for determining triplet energies. 14,21 Various sensitizers were used to transfer triplet energy to Alq 3 on pulse radiolysis of Ar saturated benzene solutions. Efficient sensitization occurred with 9-fluorenone (E triplet ) 2.19 eV; 1 eV ) 96.488 kJ mol -1 ), 22 while none was observed with acridine (E triplet ) 1.97 eV).…”

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confidence: 99%

Characterization of the Triplet State of Tris(8-hydroxyquinoline)aluminium(III) in Benzene Solution

et al. 2003

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Since Tang and VanSlyke first reported efficient electroluminescence from a device based on tris(8-hydroxyquinoline)aluminium(III) (Alq 3 ) as the luminescent layer, 1 organic light-emitting diodes (OLEDs), based on these materials, are now at the stage where they are being used as monochrome displays. This results from emission from a ligand centered π, π* excited state, formed in the transition of an electron from a highest occupied molecular orbital (MO) lying mainly on the phenoxide ring to a lowest unoccupied MO predominantly on the nitrogen atom. 2 By doping with the appropriate dyes, the emission can be tuned through the visible spectrum, 3,4 leading to the possibility of full color OLED displays. The basic processes involved are reasonably well understood, 5,6 with electroluminescence involving generation of singlet excitons from electron-hole recombination. From spin statistics, theoretical calculations, and experiment, 7 the singlet:triplet exciton ratio is 1:3, limiting the maximum internal OLED efficiency from fluorescent materials to e25%. Nevertheless, by doping with heavy atom-containing complexes, such as platinum(II) octaethylporphyrin (PtOEP), it is possible to capture triplet excitons (or charge carriers) to give electrophosphorescence, increasing internal quantum yields dramatically. 8 Although of interest for display applications, efficient exploitation requires detailed knowledge of the properties of the lowest triplet state of Alq 3 , which is not available. We are reporting here what we believe to be the first detailed characterization of this state.There is relatively little detailed information on Alq 3 photophysics. Various values have been reported for the fluorescence quantum yield 3,9,10 and lifetime, 3,11 and only indirect information exists on the triplet state. 12,13 Attempts to observe phosphorescence have proved unsuccessful, 11,12 although some information has been inferred from data on heavy metal quinolates. 11 We have shown 14 that pulse radiolysis of benzene solutions selectively produces triplet states of conjugated organic polymers by energy transfer from appropriate sensitizers following pulse radiolysis of benzene solutions. The triplet state of Alq 3 is characterized in the same way.Following pulse radiolysis 15 of an Ar saturated solution of Alq 3 (2.25 × 10 -4 M) and biphenyl (0.01 M) in benzene, the absorption of the biphenyl triplet state 16 was observed, with a maximum below 380 nm. This decayed within a few microseconds to be replaced by a new absorption maximum around 510 nm (Figure 1). This is similar to spectra reported by Ballardini et al. 11 for triplet states of various heavy metal 8-quinolinol chelates and is assigned to the Alq 3 triplet state, which decayed by good first-order kinetics with a lifetime τ ) 56.3 ( 0.4 µs. From the analysis of transient diffusion measurements in doped films, 12 a lifetime of 25 ( 15 µs was estimated for this triplet state. In contrast, a value of ca. 10 ms was reported from delayed luminescence measurements on polycrystall...

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Synthesis and Biological Evaluation of Vancomycin Dimers with Potent Activity against Vancomycin-Resistant Bacteria: Target-Accelerated Combinatorial Synthesis

et al. 2001

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Based on the notion that dimerization and/or variation of amino acid 1 of vancomycin could potentially enhance biological activity, a series of synthetic and chemical biology studies were undertaken in order to discover potent antibacterial agents. Herein we describe two ligation methods (disulfide formation and olefin metathesis) for dimerizing vancomycin derivatives and applications of target-accelerated combinatorial synthesis (e.g. combinatorial synthesis in the presence of vancomycin's target Ac2-L-Lys-D-Ala-D-Ala) to generate libraries of vancomycin dimers. Screening of these compound libraries led to the identification of a number of highly potent antibiotics effective against vancomycin-suspectible, vancomycin-intermediate resistant and, most significantly, vancomycin-resistant bacteria.

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Triplet Energies ofπ-Conjugated Polymers

Cited by 264 publications

References 29 publications

Triplet State Absorption in Carbon Nanotubes: A TD−DFT Study

Triplet State Absorption in Carbon Nanotubes: A TD−DFT Study

Characterization of the Triplet State of Tris(8-hydroxyquinoline)aluminium(III) in Benzene Solution

Synthesis and Biological Evaluation of Vancomycin Dimers with Potent Activity against Vancomycin-Resistant Bacteria: Target-Accelerated Combinatorial Synthesis

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