Multichromophore Molecular Design for Thermally Activated Delayed-Fluorescence Emitters with Near-Unity Photoluminescence Quantum Yields

2021 ◽  
Author(s):  
Dongyang Chen ◽  
Yu Kusakabe ◽  
Yongxia Ren ◽  
Dianming Sun ◽  
Pachaiyappan Rajamalli ◽  
...  
Keyword(s):  
Molecular Design ◽  
Delayed Fluorescence ◽  
Quantum Yields ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated

scholarly journals Multichromophore Molecular Design for Efficient Thermally Activated Delayed Fluorescence Emitters with Near-Unity Photoluminescence Quantum Yields

2021 ◽  
Author(s):  
Dongyang Chen ◽  
Yu Kusakabe ◽  
Yongxia Ren ◽  
Dianming Sun ◽  
P Rajamalli ◽  
...  
Keyword(s):  
Molecular Design ◽  
Light Emitting Diode ◽  
Blue Emission ◽  
Delayed Fluorescence ◽  
Quantum Yields ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Thermally Activated ◽  
Organic Light

Three multichromophore thermally activated delayed fluorescence (TADF) molecules, <b><i>p</i>-di2CzPN</b>, <b><i>m</i>-di2CzPN</b>, and<b> 1,3,5-tri2CzPN</b>, were synthesized and characterized. These molecules were designed by connecting the TADF moiety 4,5-di(9<i>H</i>-carbazol-9-yl)phthalonitrile (<b>2CzPN</b>) to different positions of a central benzene ring scaffold. Three highly soluble emitters all exhibited near quantitative photoluminescence quantum yields (<i></i><sub>PL</sub>) in toluene. High <i></i><sub>PL</sub>s were also achieved in doped films, 59% and 70% for <b><i>p</i>-di2CzPN</b> and <b><i>m</i>-di2CzPN</b> in 10 wt% DPEPO doped films, respectively, and 54% for <b>1,3,5-tri2CzPN</b> in 20 wt% doped CBP film. The rate constant of reverse intersystem crossing (<i>k</i><sub>RISC</sub>) for <b><i>p</i>-di2CzPN</b> and <b><i>m</i>-di2CzPN</b> in DPEPO films reached 1.1 × 10<sup>5</sup> s<sup>−1</sup> and 0.7 × 10<sup>5</sup> s<sup>−1</sup>, respectively, and <i>k</i><sub>RISC</sub> for <b>1,3,5-tri2CzPN</b> in CBP film reached 1.7 × 10<sup>5</sup> s<sup>−1</sup>. A solution-processed organic light-emitting diode based on <b>1,3,5-tri2CzPN </b>exhibited a sky-blue emission with CIE coordinate of (0.22, 0.44), and achieved a maximum external quantum efficiency of 7.1%.

scholarly journals Multichromophore Molecular Design for Efficient Thermally Activated Delayed Fluorescence Emitters with Near-Unity Photoluminescence Quantum Yields

2021 ◽  
Author(s):  
Dongyang Chen ◽  
Yu Kusakabe ◽  
Yongxia Ren ◽  
Dianming Sun ◽  
P Rajamalli ◽  
...  
Keyword(s):  
Molecular Design ◽  
Light Emitting Diode ◽  
Blue Emission ◽  
Delayed Fluorescence ◽  
Quantum Yields ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Thermally Activated ◽  
Organic Light

Three multichromophore thermally activated delayed fluorescence (TADF) molecules, <b><i>p</i>-di2CzPN</b>, <b><i>m</i>-di2CzPN</b>, and<b> 1,3,5-tri2CzPN</b>, were synthesized and characterized. These molecules were designed by connecting the TADF moiety 4,5-di(9<i>H</i>-carbazol-9-yl)phthalonitrile (<b>2CzPN</b>) to different positions of a central benzene ring scaffold. Three highly soluble emitters all exhibited near quantitative photoluminescence quantum yields (<i></i><sub>PL</sub>) in toluene. High <i></i><sub>PL</sub>s were also achieved in doped films, 59% and 70% for <b><i>p</i>-di2CzPN</b> and <b><i>m</i>-di2CzPN</b> in 10 wt% DPEPO doped films, respectively, and 54% for <b>1,3,5-tri2CzPN</b> in 20 wt% doped CBP film. The rate constant of reverse intersystem crossing (<i>k</i><sub>RISC</sub>) for <b><i>p</i>-di2CzPN</b> and <b><i>m</i>-di2CzPN</b> in DPEPO films reached 1.1 × 10<sup>5</sup> s<sup>−1</sup> and 0.7 × 10<sup>5</sup> s<sup>−1</sup>, respectively, and <i>k</i><sub>RISC</sub> for <b>1,3,5-tri2CzPN</b> in CBP film reached 1.7 × 10<sup>5</sup> s<sup>−1</sup>. A solution-processed organic light-emitting diode based on <b>1,3,5-tri2CzPN </b>exhibited a sky-blue emission with CIE coordinate of (0.22, 0.44), and achieved a maximum external quantum efficiency of 7.1%.

scholarly journals Molecular design of efficient yellow- to red-emissive alkynylgold(iii) complexes for the realization of thermally activated delayed fluorescence (TADF) and their applications in solution-processed organic light-emitting devices

2021 ◽  
Author(s):  
Cathay Chai Au-Yeung ◽  
Lok-Kwan Li ◽  
Man-Chung Tang ◽  
Shiu-Lun Lai ◽  
Wai-Lung Cheung ◽  
...  
Keyword(s):  
Molecular Design ◽  
Delayed Fluorescence ◽  
Solution Processed ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Thermally Activated ◽  
New Class ◽  
Organic Light ◽  
Tunable Emission

We report the design of a new class of fused heterocyclic alkynyl ligand-containing gold(iii) complexes, which shows tunable emission colors spanning yellow to red region and exhibits thermally activated delayed fluorescence (TADF) properties.

scholarly journals Solution-Processed OLEDs Based on Thermally Activated Delayed Fluorescence Copper(I) Complexes with Intraligand Charge-Transfer Excited State

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1125
Author(s):  
Teng Teng ◽  
Jinfan Xiong ◽  
Gang Cheng ◽  
Changjiang Zhou ◽  
Xialei Lv ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Density Functional ◽  
Delayed Fluorescence ◽  
Quantum Yields ◽  
Functional Theory ◽  
Solution Processed ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Thermally Activated ◽  
Wide Range

A new series of tetrahedral heteroleptic copper(I) complexes exhibiting efficient thermally-activated delayed fluorescence (TADF) in green to orange electromagnetic spectral regions has been developed by using D-A type N^N ligand and P^P ligands. Their structures, electrochemical, photophysical, and electroluminescence properties have been characterized. The complexes exhibit high photoluminescence quantum yields (PLQYs) of up to 0.71 at room temperature in doped film and the lifetimes are in a wide range of 4.3–24.1 μs. Density functional theory (DFT) calculations on the complexes reveal the lowest-lying intraligand charge-transfer excited states that are localized on the N^N ligands. Solution-processed organic light emitting diodes (OLEDs) based on one of the new emitters show a maximum external quantum efficiency (EQE) of 7.96%.

Outstanding blue delayed fluorescence and significant processing stability of cuprous complexes with functional pyridine–pyrazolate diimine ligands

2015 ◽  
Vol 44 (15) ◽  
pp. 6706-6710 ◽  
Author(s):  
Qing Zhang ◽  
Jun Chen ◽  
Xiao-Yuan Wu ◽  
Xu-Lin Chen ◽  
Rongmin Yu ◽  
...  
Keyword(s):  
Delayed Fluorescence ◽  
Quantum Yields ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Diimine Ligands ◽  
Processing Stability

Five cuprous complexes display outstanding blue thermally activated delayed fluorescence (TADF) with quantum yields near 1 and significant processing stability from the solid to the solvent states.

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%.

Controlling the exciton lifetime of blue thermally activated delayed fluorescence emitters using a heteroatom-containing pyridoindole donor moiety

2017 ◽  
Vol 4 (4) ◽  
pp. 619-624 ◽  
Author(s):  
Gyeong Heon Kim ◽  
Raju Lampande ◽  
Joon Beom Im ◽  
Jung Min Lee ◽  
Ju Young Lee ◽  
...  
Keyword(s):  
Molecular Design ◽  
Delayed Fluorescence ◽  
Energy Splitting ◽  
Triplet Energy ◽  
High Quantum Efficiency ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Exciton Lifetime ◽  
Low Efficiency ◽  
Donor Moiety

We demonstrate a promising molecular design approach to achieve short exciton lifetime, small singlet and triplet energy splitting and high photoluminescence quantum yield in thermally activated delayed fluorescence emitters for high quantum efficiency and low efficiency roll-off characteristics in OLEDs.

scholarly journals Recent advances on organic blue thermally activated delayed fluorescence (TADF) emitters for organic light-emitting diodes (OLEDs)

2018 ◽  
Vol 14 ◽  
pp. 282-308 ◽  
Author(s):  
Thanh-Tuân Bui ◽  
Fabrice Goubard ◽  
Malika Ibrahim-Ouali ◽  
Didier Gigmes ◽  
Frédéric Dumur
Keyword(s):  
Molecular Orbital ◽  
Light Emitting Diodes ◽  
Molecular Design ◽  
Delayed Fluorescence ◽  
Organic Light Emitting Diodes ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Thermally Activated ◽  
Organic Light ◽  
Recent Advances

The design of highly emissive and stable blue emitters for organic light emitting diodes (OLEDs) is still a challenge, justifying the intense research activity of the scientific community in this field. Recently, a great deal of interest has been devoted to the elaboration of emitters exhibiting a thermally activated delayed fluorescence (TADF). By a specific molecular design consisting into a minimal overlap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) due to a spatial separation of the electron-donating and the electron-releasing parts, luminescent materials exhibiting small S1–T1 energy splitting could be obtained, enabling to thermally upconvert the electrons from the triplet to the singlet excited states by reverse intersystem crossing (RISC). By harvesting both singlet and triplet excitons for light emission, OLEDs competing and sometimes overcoming the performance of phosphorescence-based OLEDs could be fabricated, justifying the interest for this new family of materials massively popularized by Chihaya Adachi since 2012. In this review, we proposed to focus on the recent advances in the molecular design of blue TADF emitters for OLEDs during the last few years.

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