Efficient up-conversion by triplet-triplet annihilation

Auckett, Josie E.; Chen, Yuen Yap; Khoury, Tony; Clady, R.; Ekins-Daukes, N. J.; Crossley, Maxwell J.; Schmidt, Timothy W.

doi:10.1088/1742-6596/185/1/012002

Cited by 42 publications

(76 citation statements)

References 10 publications

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“…These changes proceeded in the same manner as predicted by the rate equations previously developed [3] to model the scheme shown in Fig. 1.…”

Section: Figure 4 a Plot Of Steady State Absorption Of The Same Mixtumentioning

confidence: 62%

“…This transfer was observed directly through transient absorption spectroscopy of a liquid mixture of the optically active molecules. The rate of this energy transfer varied with relative concentration in the same manner as predicted by the rate model developed by J. Auckett et al [3].…”

Section: Discussionmentioning

confidence: 86%

“…The energy transfer scheme to which the results of this paper are compared [3] is shown below (see Fig. 1).…”

Section: Tta Kineticsmentioning

confidence: 99%

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Two-photon triplet-triplet annihilation upconversion for photovoltaics

Piper

Yoshida

Ekins-Daukes

et al. 2011

2011 37th IEEE Photovoltaic Specialists Conference

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Upconversion is a promising technique for significantly enhancing the efficiency of photovoltaic cells. Molecular systems provide an environment in which long lived triplet states can be exploited to achieve high upconversion efficiencies under solar illumination. We report on the investigation of bi-molecular triplet-triplet annihilation upconversion (TTA-UC) in a Palladium (II) tetrakisquinoxalino porphyrin (PQ4Pd)/rubrene solution. These molecules were studied in solution using UV/VIS spectroscopy to determine their stability in air over a period of weeks. Transient absorption spectroscopy (TAS) was used to directly measure the lifetime of triplet states within these mixtures and hence determine the photoinduced kinetics of the system. The lifetime of porphyrin triplets was reduced from 92.4 µs in pristine PQ4Pd to 2.4 µs in the presence of rubrene. From this change, the rate constant associated with triplet energy transfer (݇ ்ா் ) was calculated as 3. 38 ൈ 10 ଼ ‫ܯ‬ ିଵ ‫ݏ‬ ିଵ . Additionally, a reduction in the absorption of 530 nm light (the ground state rubrene absorption peak) was observed, while the mixture was pumped at the absorption peak of the porphyrin (670 nm). This change became apparent nearly 6 µs after the laser pulse, showing energy transfer from the porphyrin to the rubrene, and allowing further insight into the kinetics of the mechanism.

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“…These changes proceeded in the same manner as predicted by the rate equations previously developed [3] to model the scheme shown in Fig. 1.…”

Section: Figure 4 a Plot Of Steady State Absorption Of The Same Mixtumentioning

confidence: 62%

Section: Discussionmentioning

confidence: 86%

See 1 more Smart Citation

Two-photon triplet-triplet annihilation upconversion for photovoltaics

Piper

Yoshida

Ekins-Daukes

et al. 2011

2011 37th IEEE Photovoltaic Specialists Conference

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“…This finding has been further corroborated by Schmidt and coworkers. 45 Very recently, Haefele et al have shown that rigorously removing oxygen -a well known triplet quencherfrom the UC system allows one to shift the transition from the linear regime -where the quantum efficiency is maximal -to the quadratic regime towards much lower power densities than hitherto reported. 54 This has allowed them to access the linear regime when exciting a solution of PdOEP and DPA in toluene with non-coherent light of a power density of a few mW cm À2 .…”

Section: Power Dependence Triplet Concentration and Oxygen Quenchingmentioning

confidence: 99%

Low-power photon upconversion through triplet–triplet annihilation in polymers

2012

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Low-power upconversion via sensitized triplet-triplet annihilation (TTA-UC) is a useful and versatile process that allows for the conversion of optical radiation into photons of higher energy. While this effect had been known to occur in solution for some 50 years, it was only very recently realized for the first time in polymers. The possibility to realize the TTA-UC process in solid materials is important for a variety of applications that range from the optimization of photovoltaic devices to bioimaging. This article provides a brief introduction to the field, summarizes the underlying photophysical aspects, reviews the design concepts for TTA-UC in polymers, and summarizes the recent advances in the development of such materials.

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“…However, there are several critical properties of these systems that must be optimized for this technology to be viable for incorporation into real-world applications. First, because the photon UC via sensitized TTA process occurs through diffusional, bimolecular chemistry, the measurement and improvement of the quantum efficiency in these systems becomes crucial [20,22,35,46]. Second, in order to reap the greatest benefits from these compositions, it is necessary to maximize the anti-Stokes shift that can be achieved.…”

Section: Introductionmentioning

confidence: 99%

Photon upconversion sensitized by a Ru(II)-pyrenyl chromophore

Deng

Lazorski

Castellano

2015

Phil. Trans. R. Soc. A.

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One contribution of 11 to a discussion meeting issue 'Organic semiconductor spintronics: utilizing triplet excitons in organic electronics' . The near-visible-to-blue singlet fluorescence of anthracene sensitized by a ruthenium chromophore with a long-lived triplet-excited state, [Ru(5-pyrenyl-1,10-phenanthroline) 3 ](PF 6 ) 2 , in acetonitrile was investigated. Low intensity non-coherent green light was used to selectively excite the sensitizer in the presence of micromolar concentrations of anthracene generating anti-Stokes, singlet fluorescence in the latter, even with incident power densities below 500 µW cm −2 . The resultant data are consistent with photon upconversion proceeding from sensitized triplet-triplet annihilation (TTA) of the anthracene acceptor molecules, confirmed through transient absorption spectroscopy as well as static and dynamic photoluminescence experiments. Additionally, quadratic-to-linear incident power regimes for the upconversion process were identified for this composition under monochromatic 488 nm excitation, consistent with a sensitized TTA mechanism ultimately producing the anti-Stokes emission characteristic of anthracene singlet fluorescence.

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Efficient up-conversion by triplet-triplet annihilation

Cited by 42 publications

References 10 publications

Two-photon triplet-triplet annihilation upconversion for photovoltaics

Two-photon triplet-triplet annihilation upconversion for photovoltaics

Low-power photon upconversion through triplet–triplet annihilation in polymers

Photon upconversion sensitized by a Ru(II)-pyrenyl chromophore

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