Dual Fluorescence and Excited-State Structural Relaxations in Donor−Acceptor Stilbenes

Twisting of the NMe2 group in p-N,N-dimethylaminobenzonitrile (DMABN) was investigated using AM1 semiempirical method with configuration interaction. Effect of polar media was considered by placing + and - charge centers ("sparkles") at appropriate places opposite the molecule. Optimized ground state geometry of DMABN is slightly twisted with the lowest vertical excited state of 1B character. As the polarity of media increases and/or the - NMe2 group twists, the symmetric 1A excited state having considerable charge separation becomes energetically favorable. Anomalous long-wavelength emission of DMABN comes from this state.

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Thermochromic aggregation-induced dual phosphorescence via temperature-dependent sp3-linked donor-acceptor electronic coupling

Nature Communications ◽

10.1038/s41467-021-21676-5 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Tao Wang ◽

Zhubin Hu ◽

Xiancheng Nie ◽

Linkun Huang ◽

Miao Hui ◽

...

Keyword(s):

Excited State ◽

Room Temperature ◽

Electronic Coupling ◽

Temperature Dependent ◽

Molecular Systems ◽

Donor And Acceptor ◽

Theoretical Investigations ◽

Donor Acceptor ◽

And Control ◽

Two Temperature

AbstractAggregation-induced emission (AIE) has proven to be a viable strategy to achieve highly efficient room temperature phosphorescence (RTP) in bulk by restricting molecular motions. Here, we show that by utilizing triphenylamine (TPA) as an electronic donor that connects to an acceptor via an sp3 linker, six TPA-based AIE-active RTP luminophores were obtained. Distinct dual phosphorescence bands emitting from largely localized donor and acceptor triplet emitting states could be recorded at lowered temperatures; at room temperature, only a merged RTP band is present. Theoretical investigations reveal that the two temperature-dependent phosphorescence bands both originate from local/global minima from the lowest triplet excited state (T1). The reported molecular construct serves as an intermediary case between a fully conjugated donor-acceptor system and a donor/acceptor binary mix, which may provide important clues on the design and control of high-freedom molecular systems with complex excited-state dynamics.

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Electronic spectral study of interaction of electron donor – acceptor dyes in the ground and excited state with a metal ion. Effect of molecular structure of the dye

Journal of Luminescence ◽

10.1016/j.jlumin.2013.07.019 ◽

2014 ◽

Vol 145 ◽

pp. 25-32 ◽

Cited By ~ 1

Author(s):

Sanjib Kr Sardar ◽

Prasun K. Mandal ◽

Sanjib Bagchi

Keyword(s):

Molecular Structure ◽

Excited State ◽

Electron Donor ◽

Spectral Study ◽

Metal Ion ◽

Donor Acceptor ◽

Electronic Spectral Study

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Charge separation in the excited state electron donor—acceptor compounds containing the piperazine moiety

Chemical Physics Letters ◽

10.1016/0009-2614(91)85009-l ◽

1991 ◽

Vol 180 (6) ◽

pp. 556-562 ◽

Cited By ~ 8

Author(s):

A.M. Brouwer ◽

R.D. Mout ◽

P.H.Maassen van den Brink ◽

H.J. van Ramesdonk ◽

J.W. Verhoeven ◽

...

Keyword(s):

Excited State ◽

Electron Donor ◽

Charge Separation ◽

State Electron ◽

Donor Acceptor

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Regioisomeric Effect on the Excited-State Fate Leading to Room-Temperature Phosphorescence or Thermally Activated Delayed Fluorescence in a Dibenzophenazine-Cored Donor–Acceptor–Donor System

10.26434/chemrxiv-2021-6672t ◽

2021 ◽

Author(s):

Takumi Hosono ◽

Nicolas Oliveira Decarli ◽

Paola Zimmermann Crocomo ◽

Tsuyoshi Goya ◽

Leonardo Evaristo de Sousa ◽

...

Keyword(s):

Excited State ◽

Room Temperature ◽

Delayed Fluorescence ◽

Quantum Yields ◽

Room Temperature Phosphorescence ◽

Thermally Activated Delayed Fluorescence ◽

Light Emitting ◽

Thermally Activated ◽

Donor Acceptor ◽

Emission Behavior

Exploring design principle for switching thermally activated dealyed fluorescecne (TADF) and room temperature phosphorescence (RTP) is a fundamentally imporant research in developing triplet-mediated photofunctional organic materials. Herein systematic studies on the regioisomeric and substituents effects in a twisted donor–acceptor–donor (D–A–D) scaffold (A = dibenzo[a,j]phenazine; D = dihydrophenazasiline) on the fate of the excited state have been performed. The study revealed that the regiosiomerism clearly affects the emission behavior of the D–A–D compounds. Distinct difference in TADF, dual TADF & RTP, and dual RTP were observed, depending on the host used. Furthermore, OLED organic light-emitting diodes (OLEDs) fabricated with the developed emitters achieved high external quantum yields for RTP-based OLEDS up to 7.4%.

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