Novel efficient blue and bluish-green light-emitting polymers with delayed fluorescence

2018 ◽  
Vol 6 (11) ◽  
pp. 2690-2695 ◽  
Author(s):  
Yingyuan Hu ◽  
Wanqing Cai ◽  
Lei Ying ◽  
Dongjun Chen ◽  
Xiye Yang ◽  
...  
Keyword(s):  
Green Light ◽  
Coupling Reaction ◽  
Delayed Fluorescence ◽  
Light Emitting ◽  
Bluish Green ◽  
Palladium Catalyzed ◽  
Donor Acceptor

Donor–acceptor type polymers with delayed fluorescence are synthesized via a palladium catalyzed C–N coupling reaction.

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.

Preparation and Luminescence Properties of Polymeric 2,5-Bis[2´-(8´´-alkoxyquinolin-2´´-yl)ethenyl]hydroquinone Derivatives

2002 ◽  
Vol 55 (8) ◽  
pp. 499 ◽  
Author(s):  
M.-A. Hsu ◽  
T. J. Chow
Keyword(s):  
Reduction Potential ◽  
Light Emitting Diode ◽  
Monomer Unit ◽  
Green Light ◽  
Emission Spectra ◽  
Coupling Reaction ◽  
Hydroxyl Groups ◽  
High Solubility ◽  
Light Emitting ◽  
Coumarin 6

A PPV-type polymer (1) incorporating 5,5�-diquinolinyl moieties is prepared by a Yamamoto homo-coupling reaction from the dibromide (2). Since all the hydroxyl groups were alkylated, this polymer showed high solubility in most organic solvents. It can be spin-coated readily to form a thin layer in the fabrication of light emitting diode (LED) devices. The adjacent quinoline rings are twisted to form a dihedral angle due to steric hindrance, so that π-conjugation is confined within each monomer unit. The emission spectra of (1) and (2) are nearly identical. The reduction potential of (1) was estimated to be –1.10 V (onset), with a band gap of 2.53 eV (490 nm). A single hetero-junction LED device fabricated by combining the films of poly(vinylkarbazol) (PVK) and (1) yielded promising results. The device ITO/PVK/(1)/Ca/Al exhibited a turn-on voltage at 6 V and reached a maximal brightness of 250 cd/m2 at 15 V. An alternate potential usage of (1) as an electron-injecting material was also explored on a green-light device using coumarin-6 as an emitter.

scholarly journals Synthesis and optical properties of new 5'-aryl-substituted 2,5-bis(3-decyl-2,2'-bithiophen-5-yl)-1,3,4-oxadiazoles

2017 ◽  
Vol 13 ◽  
pp. 313-322 ◽  
Author(s):  
Anastasia Sergeevna Kostyuchenko ◽  
Tatyana Yu Zheleznova ◽  
Anton Jaroslavovich Stasyuk ◽  
Aleksandra Kurowska ◽  
Wojciech Domagala ◽  
...  
Keyword(s):  
Optical Properties ◽  
Quantum Chemical ◽  
Emission Spectra ◽  
Aryl Halides ◽  
Aryl Substituent ◽  
Tddft Calculations ◽  
Terminal Substituent ◽  
Bluish Green ◽  
Palladium Catalyzed ◽  
Donor Acceptor

New photoluminescent donor–acceptor–donor (DAD) molecules, namely 5'-aryl-substituted 2,5-bis(3-decyl-2,2'-bithiophen-5-yl)-1,3,4-oxadiazoles were prepared by palladium-catalyzed coupling from readily available compounds such as ethyl 3-decyl-2,2'-bithiophene-5-carboxylate and aryl halides. The obtained compounds feature increasing bathochromic shifts in their emission spectra with increasing aryl-substituent size yielding blue to bluish-green emissions. At the same time, their absorption spectra are almost independent from the identity of the terminal substituent with λmax values ranging from 395 to 405 nm. The observed trends are perfectly predicted by quantum chemical DFT/TDDFT calculations carried out for these new molecules.

The Effect of Molecular Aggregation of Thermally Activated Delayed Fluorescence Sensitizer for Hyperfluorescence in Organic Light-Emitting Diodes

2021 ◽  
Author(s):  
Eun Young Park ◽  
Ji Hyun Park ◽  
Yun-Hi Kim ◽  
Min Chul Suh
Keyword(s):  
Resonance Effect ◽  
Delayed Fluorescence ◽  
Organic Light Emitting Diodes ◽  
Synthetic Material ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Thermally Activated ◽  
Organic Light ◽  
Phenyl Sulfone ◽  
Donor Acceptor

The exciton behavior of a new synthetic material, 11-phenyl-11H-9,16-dioxa-11-aza-4b-boraindeno[1,2-a]naphtho[3,2,1-de] anthracene (Ph-OBNA), which displays a multi-resonance effect, and bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (DMAC-DPS) with a donor–acceptor-donor structure was analyzed. First, we conducted quantum mechanical...

Ultrathin Non-doped Thermally Activated Delayed Fluorescence Emitting Layer for Highly Efficient OLEDs

2021 ◽  
Author(s):  
Gyana Prakash Nanda ◽  
Bahadur Sk ◽  
Nisha Yadav ◽  
Suresh Rajamanickam ◽  
Upasana Deori ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Delayed Fluorescence ◽  
Organic Light Emitting Diodes ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Thermally Activated ◽  
Highly Efficient ◽  
Organic Light ◽  
Bluish Green

We report highly efficient, ultrathin non-doped green and bluish-green organic light-emitting diodes (OLEDs) using a thermally activated delayed fluorescence (TADF) emitter. The green OLED with an ultrathin (~1 nm) EML...

Maximizing TADF via Conformational Optimization

2021 ◽  
Author(s):  
Changhae Andrew Kim ◽  
Troy Van Voorhis
Keyword(s):  
Density Functional ◽  
Minimum Energy ◽  
Delayed Fluorescence ◽  
New Paradigm ◽  
Light Emitting ◽  
Td Dft ◽  
New Strategy ◽  
Donor Acceptor ◽  
The Right ◽  
Geometric Changes

We investigate a new strategy to enhance thermally activated delayed fluorescence (TADF) in organic light-emitting diodes (OLEDs). Given that the TADF rate of a molecule depends on its conformation, we hypothesize that there exists a conformation that maximizes the TADF rate. In order to test this idea, we use time-dependent density functional theory (TD-DFT) to simulate the TADF rates of several TADF emitters, while shifting their geometries towards higher TADF rates in a select subspace of internal coordinates. We find that geometric changes in this subspace can increase the TADF rate up to three orders of magnitude with respect to the minimum energy conformation, and the simulated TADF rate can even be brought into the submicrosecond timescales under the right conditions. Furthermore, the rate enhancement can be maintained with a conformational energy that are within the reach of modern synthetic chemistry. Analyzing the maximum TADF conformation, we extract a number of structural motifs that might provide a useful handle on the TADF rate of a donor-acceptor (DA) system. The incorporation of conformational engineering into the TADF technology could usher in a new paradigm of OLEDs.

Sign in / Sign up

Export Citation Format

Share Document