scholarly journals The interplay of thermally activated delayed fluorescence (TADF) and room temperature organic phosphorescence in sterically-constrained donor–acceptor charge-transfer molecules

2016 ◽  
Vol 52 (12) ◽  
pp. 2612-2615 ◽  
Author(s):  
Jonathan S. Ward ◽  
Roberto S. Nobuyasu ◽  
Andrei S. Batsanov ◽  
Przemyslaw Data ◽  
Andrew P. Monkman ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Room Temperature ◽  
Delayed Fluorescence ◽  
Molecular Engineering ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Donor Acceptor

Molecular engineering of phenothiazine–dibenzothiophene-S,S-dioxide molecules is reported.

scholarly journals 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

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%.

scholarly journals Synthesis and optoelectronic properties of benzoquinone-based donor–acceptor compounds

2019 ◽  
Vol 15 ◽  
pp. 2914-2921
Author(s):  
Daniel R Sutherland ◽  
Nidhi Sharma ◽  
Georgina M Rosair ◽  
Ifor D W Samuel ◽  
Ai-Lan Lee ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Delayed Fluorescence ◽  
Optoelectronic Properties ◽  
Donor Group ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Palladium Catalyzed ◽  
Donor Acceptor

Herein, we report a mild and efficient palladium-catalyzed C–H functionalization method to synthesize a series of benzoquinone (BQ)-based charge-transfer (CT) derivatives in good yields. The optoelectronic properties of these compounds were explored both theoretically and experimentally and correlations to their structures were identified as a function of the nature and position of the donor group (meta and para) attached to the benzoquinone acceptor. Compound 3, where benzoquinone is para-conjugated to the diphenylamine donor group, exhibited thermally activated delayed fluorescence (TADF) with a biexponential lifetime characterized by a prompt ns component and a delayed component of 353 μs.

scholarly journals Intramolecular Through-Space Charge-Transfer Emitters Featuring Thermally Activated Delayed Fluorescence for High-Efficiency Electroluminescent Devices

2021 ◽  
Author(s):  
Yongjun song ◽  
lei he ◽  
Mingxing Tian ◽  
Renyou Yu
Keyword(s):  
Charge Transfer ◽  
Space Charge ◽  
High Efficiency ◽  
Theoretical Calculations ◽  
Delayed Fluorescence ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Thermally Activated ◽  
Donor Acceptor ◽  
First Time

Through-space charge-transfer (TSCT) emitters have been extensively explored for thermally activated delayed fluorescence (TADF), but arranging various donors and acceptors into rigid cofacial conformations for various efficient TSCT TADF emitters has still remained a challenge. Here we report for the first time a “fixing acceptor” design to reach various efficient TSCT TADF emitters. By chemically fixing the acceptor (benzophenone) with a rigid spiro structure and cofacially aligning various donors with the fixed acceptor, a series of efficient TSCT TADF emitters have been developed. Single-crystal structures and theoretical calculations have verified closely-packed cofacial donor/acceptor conformations and favorable TSCT in the emitters. The emitters afford sky-blue to yellow TADF emission in doped films, with high photoluminescent efficiencies of up to 0.92 and reverse intersystem crossing rates of up to 1.0×106 s−1. Organic light-emitting diodes using the emitters afford sky-blue to yellow electroluminescence with high external quantum efficiencies of up to 20.9%. The work opens a new avenue toward a wide variety of efficient TSCT TADF emitters.

Bridge control of photophysical properties in benzothiazole-phenoxazine emitters – from thermally activated delayed fluorescence to room temperature phosphorescence

2022 ◽  
Author(s):  
Simon PAREDIS ◽  
Tom CARDEYNAELS ◽  
Jasper DECKERS ◽  
Andrew Danos ◽  
Dirk Vanderzande ◽  
...  
Keyword(s):  
Room Temperature ◽  
Photophysical Properties ◽  
Phenyl Group ◽  
Delayed Fluorescence ◽  
Room Temperature Phosphorescence ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Thiophene Moiety ◽  
Donor Acceptor

The bridging phenyl group in a fluorescent phenoxazine-benzothiazole donor-acceptor dyad is replaced by either a naphthalene or a thiophene moiety to probe the influence of a more extended conjugated system...

scholarly journals Revealing Internal Heavy Chalcogen Atom Effect on the Photophysics of Dibenzo[a,j]phenazine-Cored Donor–Acceptor–Donor Triad

2021 ◽  
Author(s):  
Shimpei Goto ◽  
Yuya Nitta ◽  
Nicolas Decarli ◽  
Leonardo Evaristo de Sousa ◽  
Patrycja Stachelek ◽  
...  
Keyword(s):  
Room Temperature ◽  
Photophysical Properties ◽  
Heavy Atom ◽  
Delayed Fluorescence ◽  
Room Temperature Phosphorescence ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Donor Acceptor ◽  
Mechanochromic Luminescence ◽  
Atom Effect

<div><div><div><p>A new twisted donor–acceptor–donor (D–A–D) multi-photofunctional organic molecule comprising of phenoselenazine as the electron-donors (Ds) and dibenzo[a,j]phenazine (DBPHZ) as the electron-acceptor (A) has been developed. The developed selenium-incorporated D–A–D compound is featured with multi-color polymorphism, distinct mechanochromic luminescence, chemically-stimulated luminochromism, thermally-activated delayed fluorescence, and room- temperature phosphorescence. The internal heavy atom effect on the photophysical properties of the D–A–D system has been investigated through the comparison with the physicochemical properties of a previously developed sulfur analogue and a tellurium analogue.</p></div></div></div>

scholarly journals Revealing Internal Heavy Chalcogen Atom Effect on the Photophysics of Dibenzo[a,j]phenazine-Cored Donor–Acceptor–Donor Triad

2021 ◽  
Author(s):  
Shimpei Goto ◽  
Yuya Nitta ◽  
Nicolas Decarli ◽  
Leonardo Evaristo de Sousa ◽  
Patrycja Stachelek ◽  
...  
Keyword(s):  
Room Temperature ◽  
Photophysical Properties ◽  
Heavy Atom ◽  
Delayed Fluorescence ◽  
Room Temperature Phosphorescence ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Donor Acceptor ◽  
Mechanochromic Luminescence ◽  
Atom Effect

<div><div><div><p>A new twisted donor–acceptor–donor (D–A–D) multi-photofunctional organic molecule comprising of phenoselenazine as the electron-donors (Ds) and dibenzo[a,j]phenazine (DBPHZ) as the electron-acceptor (A) has been developed. The developed selenium-incorporated D–A–D compound is featured with multi-color polymorphism, distinct mechanochromic luminescence, chemically-stimulated luminochromism, thermally-activated delayed fluorescence, and room- temperature phosphorescence. The internal heavy atom effect on the photophysical properties of the D–A–D system has been investigated through the comparison with the physicochemical properties of a previously developed sulfur analogue and a tellurium analogue.</p></div></div></div>

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