Triplet-triplet transfer of electronic excitation energy in vapors of organic molecules

Zalesskaya, G. A.; Pavlova, V. T.; Yakovlev, D. L.; Sambor, E. G.; Belyi, N. N.

doi:10.1134/1.1531707

Cited by 5 publications

(5 citation statements)

References 12 publications

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“…The red spectrum in Figure 1 illustrates that 90 mM DMA yields singlet fluorescence in the blue region in addition to strong excimeric emission at longer wavelengths between 500 and 700 nm. 7 The singlet and triplet energies of DMA previously were reported as ∼25 000 and 14 700 cm -1 , 10,11 respectively, thereby making DMA an attractive energy transfer quencher for the triplet excited state of [Ru(dmb) 3 ] 2+ . The singlet fluorescence quantum yield of DMA in DMF was reported to approach unity in DMF, whereas the triplet quantum yield and lifetime of this chromophore in deaerated DMF were reported to be 0.02 and 4 ms, respectively.…”

Section: Resultsmentioning

confidence: 99%

Photochemical Upconversion Approach to Broad-Band Visible Light Generation

2008

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The sensitized triplet-triplet annihilation (TTA) of 9,10-dimethylanthracene (DMA) upon selective excitation of [Ru(dmb)3]2+ (dmb = 4,4'-dimethyl-2,2'-bipyridine) at 514.5 nm in dimethylformamide (DMF) resulted in upconverted and downconverted DMA excimer photoluminescence. The triplet excited state of [Ru(dmb)3]2+ is efficiently quenched by 11 mM DMA in DMF resulting in photon upconversion but no excimer formation. The bimolecular quenching constant of the dynamic quenching process is 1.4 x 109 M-1 s-1. At 90 mM DMA, both upconversion and downconversion processes are readily observed in aerated DMF solutions. The TTA process was confirmed by the quadratic dependence of the upconverted and downconverted emission emanating from the entire integrated photoluminescence profile (400-800 nm) of DMA measured with respect to incident light power. Time-resolved emission spectra of [Ru(dmb)3]2+ and 90 mM DMA in both aerated and deaerated DMF clearly illustrates the time-delayed nature of both types of singlet-state emission, which interestingly shows similar decay kinetics on the order of 14 mus. The emission quantum yields (Phi) measured using relative actinometry increased with increasing DMA concentrations, reaching a plateau at 3.0 mM DMA (Phi = 4.0%), while at 90 mM DMA, the overall quantum yield diminished to 0.5%. The dominant process occurring at 3.0 mM DMA is upconversion from the singlet excited state of DMA, whereas at 90 mM DMA, both upconversion and excimeric emission are observed in almost equal portions, thereby resulting in an overall broad-band visible light-emission profile.

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Section: Resultsmentioning

confidence: 99%

Photochemical Upconversion Approach to Broad-Band Visible Light Generation

2008

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“…For Ac, where SF is energetically forbidden (S 0 ← S 1 : 3.43 eV 54 , 2•(S 0 ← T 1 ): 3.66 eV55 , for unbound molecules), a slightly different, but still similar to Tc…”

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confidence: 96%

Excitation dynamics in polyacene molecules on rare-gas clusters

Bohlen,

Michiels,

Michelbach

et al. 2022

Preprint

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Laser-induced fluorescence spectra and excitation lifetimes of anthracene, tetracene, and pentacene molecules attached to the surface of solid argon clusters have been measured with respect to cluster size, density of molecules and excitation density.Results are compared to previous studies on the same sample molecules attached to neon clusters. A contrasting lifetime behavior of anthracene on neon and argon clusters is discussed, and mechanisms are suggested to interpret the results. Although both neon and argon clusters are considered to be weakly interacting environments, we find that the excitation decay dynamics of the studied acenes depends significantly on the cluster material. Moreover, we find even qualitative differences regarding the dependence on the dopant density. Based on these observations, previous assignments of collective radiative and non-radiative decay mechanisms are discussed in the context of the new experimental findings.

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“…The deviations noted for some pairs (anthraquinone-diacetyl, diacetylnaphthalene) may be due to one of many different factors. Among the most important factors is the strengthening of the influence of the back transfer with increasing temperature [36,38]. The triplet energy transfer in the region of the normal dependence is characterized by positive activation energies having relatively low values: 824 cm −1 (diacetyl-anthracene), 695 cm −1 (diacetyl-naphthalene), and 206 cm −1 (anthraquinone-diacetyl).…”

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confidence: 99%

“…The increase in the exothermal transfer efficiency with increasing temperature revealed for some pairs contradicts the ideas about the transfer intensification due to the formation of a delayed collisional complex, since with increasing temperature the probability of forming a complex decreases. In [39,40], attention was drawn to the influence of the internal reorganization energy of donor molecules on the T-T transfer rate constants, but the first direct proofs of the important role of this factor were obtained from the experimental data in the gas phase [35][36][37], where the contribution of the solvent reorganization energy was completely excluded.…”

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confidence: 99%

“…To estimate the rate constants and efficiencies of the T-T electron energy transfer, the widely used method for investigating the T-T transfer by the quenching of the delayed luminescence (phosphorescence and DF) of the donor by the acceptor and by the sensitization of delayed fluorescences of acceptors was employed [11,[33][34][35][36][37][38]. The temperature dependences of the kinetic characteristics of the T-T transfer were investigated for seven DA pairs in the 363-513 K temperature range.…”

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confidence: 99%

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Intermolecular Processes in Excited Electronic States in the Gas Phase (Review)

Zalesskaya

Sambor

2005

J Appl Spectrosc

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A brief review of works on the temperature dependences of the rate constants k q of the intermolecular processes proceeding in the excited electronic states in the gas phase is given. The dependences k q (T) for such biomolecular processes as intermolecular vibrational energy transfer in the triplet state vibrational quasi-continuum, triplet-triplet electron excitation energy transfer, and intermolecular photoinduced electron transfer have been compared. The experimental data have shown that in the gas phase for all analyzed intermolecular processes both an increase and a decrease in k q with increasing temperature (T) is observed, which is not associated with the specific intermolecular interactions leading to the formation of long-lived components. The change in the type of temperature dependence is due to the change in the mechanisms of the radiationless transitions with increasing density of vibrational levels in the final electronic state. The applicability of the known models based on the theory of radiationless transitions for predicting the temperature dependences k q (T) is discussed.Keywords: temperature dependence of the rate constants of intermolecular processes, intermolecular vibrational energy transfer, triplet-triplet energy transfer, photoinduced intermolecular electron transfer.Introduction. Biomolecular processes play an important part in gaseous media such as the atmosphere, gaseous mixtures resulting from combustion and explosions, working mixtures of gas lasers, gaseous mixtures of isotopes, etc. In real molecular mixtures, the yield of photochemical reactions depends on the efficiency of the electron and vibrational energy exchange and transfer. The temperature dependences of the probability of collisional processes are of fundamental interest both for studying the nature of intermolecular interactions deactivating excited molecules and testing theoretical models. The practical interest in such studies is primarily due to the necessity of estimating the yield of gas-phase reactions in a wide range of temperatures.In analyzing the intermolecular processes in the excited electronic states, it is usually assumed that their rates increase with increasing temperature. Negative temperature dependences are considered as a result of specific intermolecular interactions leading to the formation of stable complexes of various nature. The most detailed theoretical studies of the temperature dependence of the energy transfer probability have been made for the intermolecular vibrational relaxation of small molecules in the system of discrete vibrational levels [1]. It has been shown that for this intermolecular process both positive and negative temperature dependences of the rate constants and the energy transfer efficiencies are possible. For the triplet-triplet (T-T) electron excitation energy transfer and the intermolecular photoinduced electron transfer (PET), the possibilities of modeling the temperature changes in the process probability were discussed only for some special cases in [2] and [3, 4...

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Triplet-triplet transfer of electronic excitation energy in vapors of organic molecules

Cited by 5 publications

References 12 publications

Photochemical Upconversion Approach to Broad-Band Visible Light Generation

Photochemical Upconversion Approach to Broad-Band Visible Light Generation

Excitation dynamics in polyacene molecules on rare-gas clusters

Intermolecular Processes in Excited Electronic States in the Gas Phase (Review)

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