Anti-Kasha behavior of DMABN dual fluorescence

Томин, В. И.; Włodarkiewicz, Agnieszka

doi:10.1016/j.jlumin.2018.02.041

Cited by 7 publications

(6 citation statements)

References 33 publications

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“…[239][240][241][242][243] Other categories of push-pull systems may be useful as dopants to produce devices with novel optoelectronic properties, including photoswitchable molecules, 244 and molecules that exhibit TADF without the use of heavy metals. [245][246][247] Dual fluorescence represents an exception to Kasha's rule, [248][249][250][251] which states that emission typically occurs in a single band originating from the lowest excited state, insofar as radiationless internal conversion from higher-lying excited states is usually rapid and efficient. The dependence on solvent polarity has long been been interpreted in terms of excited-state dynamics that access a twisted intramolecular CT (TICT) state, characterized by rotation of the -N(CH 3 ) 2 group out of the phenyl plane.…”

Section: Charge-transfer Numbersmentioning

confidence: 99%

Visualizing and characterizing excited states from time-dependent density functional theory

Herbert

2024

Phys. Chem. Chem. Phys.

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Section: Charge-transfer Numbersmentioning

confidence: 99%

Visualizing and characterizing excited states from time-dependent density functional theory

Herbert

2024

Phys. Chem. Chem. Phys.

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“…The observation of a longer T 2 lifetime compared to that of T 1 at 77 K ( Figure 4 a) implies anti-Kasha behavior in 1 [ 38 , 39 , 40 ]. This suggests that 1 shows different RTP behavior to 2 and 3 .…”

Section: Resultsmentioning

confidence: 91%

“…These bands were typical of the benzil moiety [ 30 , 32 ], but not tolane [ 33 , 34 , 35 , 36 , 37 ]. An emission from higher excited states implied anti-Kasha behavior, and many molecules were known to exhibit the emission [ 13 , 38 , 39 ]. It is worth noting that we confirmed that the flu.…”

Section: Resultsmentioning

confidence: 99%

Excited-State Dynamics of Room-Temperature Phosphorescent Organic Materials Based on Monobenzil and Bisbenzil Frameworks

et al. 2020

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Room-temperature phosphorescent (RTP) materials have been attracting tremendous interest, owing to their unique material characteristics and potential applications for state-of-the-art optoelectronic devices. Recently, we reported the synthesis and fundamental photophysical properties of new RTP materials based on benzil, i.e., fluorinated monobenzil derivative and fluorinated and non-fluorinated bisbenzil derivative analogues [Yamada, S. et al., Beilstein J. Org. Chem. 2020, 16, 1154–1162.]. To deeply understand their RTP properties, we investigated the excited-state dynamics and photostability of the derivatives by means of time-resolved and steady-state photoluminescence spectroscopies. For these derivatives, clear RTP emissions with lifetimes on the microsecond timescale were identified. Among them, the monobenzil derivative was found to be the most efficient RTP material, showing both the longest lifetime and highest amplitude RTP emission. Time-resolved photoluminescence spectra, measured at 77 K, and density functional theory calculations revealed the existence of a second excited triplet state in the vicinity of the first excited singlet state for the monobenzil derivative, indicative of the presence of a fast intersystem crossing pathway. The correlation between the excited state dynamics, emission properties, and conformational flexibility of the three derivatives is discussed.

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“…The manipulation of the excited-state evolution is predominant in this area, possessing several scientific and technological merits. − For most organic luminogens, emission is generally from the relaxation of excitons in the first excited electron states (S 1 ) to the ground state (S 0 ), which is known as the Kasha’s rule. − When these excited states are close to each other, the vibrational relaxation and internal conversion occur quickly, leading to an emission from the upper excited states (S 2 , S 3 , ...) that is hardly observed. On the contrary, the enlargement of the energy gap between S 1 and upper states can be an effective approach to obtain anti-Kasha’s rule emission. − Anti-Kasha’s rule emissions are currently of huge theoretical and experimental interests because such an emissive pathway can ideally avoid additional consumption from internal conversions and other forms of electronic relaxation for benefiting the luminescent quantum efficiency. Azulene (C 10 H 8 ), an isomer of naphthalene, composed of an electron-rich five-membered ring and an electron-deficient seven-membered ring, can form resonant cyclopentadienide anion and tropylium cation substructures.…”

Section: Introductionmentioning

confidence: 99%

Multiwavelength Anti-Kasha’s Rule Emission on Self-Assembly of Azulene-Functionalized Persulfurated Arene

et al. 2019

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Organic emitters that can give birth to emission from highly excited states have been of unique interest currently, whereas ways to strengthen the so-called anti-Kasha's rule emission at the chemistry level are still limited. Since the appearance and improvement of this emission pathway connects to the special potential of avoiding additional consumption from internal conversions and other forms of electronic relaxation processes, we here report the synthesis and photophysical study of a molecular structure consisting of cyanostyryl-modified azulene and hexathiobenzene core to exhibit a largely enhanced multiwavelength anti-Kasha's rule luminescence. Such an emission pathway in this compound can be effectively tuned and strengthened in response to the aggregation-induced emission effect as well as the fluorescence resonance energy transfer process, which totally allow a ca. 15-fold amplification of the quantum yield of this material as compared to the routine precursors. Moreover, the luminescence in this system can also be smartly regulated by many factors including protonation, light irradiation, and solution type. Enhanced emission can be maintained in the dye-doped polymer film, providing new visions for the development of advanced solid-state emissive materials.

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Anti-Kasha behavior of DMABN dual fluorescence

Cited by 7 publications

References 33 publications

Visualizing and characterizing excited states from time-dependent density functional theory

Visualizing and characterizing excited states from time-dependent density functional theory

Excited-State Dynamics of Room-Temperature Phosphorescent Organic Materials Based on Monobenzil and Bisbenzil Frameworks

Multiwavelength Anti-Kasha’s Rule Emission on Self-Assembly of Azulene-Functionalized Persulfurated Arene

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