Manipulating the Electronic Excited State Energies of Pyrimidine-Based Thermally Activated Delayed Fluorescence Emitters To Realize Efficient Deep-Blue Emission

2017 ◽  
Vol 9 (5) ◽  
pp. 4742-4749 ◽  
Author(s):  
Ryutaro Komatsu ◽  
Tatsuya Ohsawa ◽  
Hisahiro Sasabe ◽  
Kohei Nakao ◽  
Yuya Hayasaka ◽  
...  
Keyword(s):  
Excited State ◽  
Blue Emission ◽  
Delayed Fluorescence ◽  
Thermally Activated Delayed Fluorescence ◽  
Electronic Excited State ◽  
Thermally Activated ◽  
Deep Blue

scholarly journals Efficient Deep-Blue Electroluminescence Employing Heptazine-Based Thermally Activated Delayed Fluorescence

Photonics ◽  
2021 ◽  
Vol 8 (8) ◽  
pp. 293
Author(s):  
Jie Li ◽  
Jincheng Zhang ◽  
Heqi Gong ◽  
Li Tao ◽  
Yanqing Wang ◽  
...  
Keyword(s):  
High Performance ◽  
Light Emitting Diode ◽  
Blue Emission ◽  
Delayed Fluorescence ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Thermally Activated ◽  
Deep Blue ◽  
Blue Emitters

We report an efficient deep-blue organic light-emitting diode (OLED) based on a heptazine-based thermally activated delayed fluorescent (TADF) emitter, 2,5,8-tris(diphenylamine)-tri-s-triazine (HAP-3DPA). The deep-blue-emitting compound, HAP-3DPA, was designed and synthesized by combining the relatively rigid electron-accepting heptazine core with three electron-donating diphenylamine units. Due to the rigid molecular structure and intramolecular charge transfer characteristics, HAP-3DPA in solid state presented a high photoluminescence quantum yield of 67.0% and obvious TADF nature with a short delayed fluorescent lifetime of 1.1 μs. Most importantly, an OLED incorporating HAP-3DPA exhibited deep-blue emission with Commission Internationale de l’Eclairage (CIE) coordinates of (0.16, 0.13), a peak luminance of 10,523 cd/m−2, and a rather high external quantum efficiency of 12.5% without any light out-coupling enhancement. This finding not only reports an efficient deep-blue TADF molecule, but also presents a feasible pathway to construct high-performance deep-blue emitters and devices based on the heptazine skeleton.

Donor–acceptor materials exhibiting deep blue emission and thermally activated delayed fluorescence with tris(triazolo)triazine

2021 ◽  
Author(s):  
Ryoga Hojo ◽  
Don M. Mayder ◽  
Zachary M. Hudson
Keyword(s):  
Blue Emission ◽  
Delayed Fluorescence ◽  
Fluorescence Properties ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Two Photon ◽  
Deep Blue ◽  
Donor Acceptor ◽  
Two Photon Fluorescence ◽  
Photon Fluorescence

Five emitters with the tris(triazolo)triazine acceptor core are reported, with emission from deep blue to green. These emitters show promising thermally activated delayed fluorescence and/or two-photon fluorescence properties.

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%.

Thermally activated delayed fluorescence materials as organic photosensitizers

2021 ◽  
Vol 57 (82) ◽  
pp. 10675-10688
Author(s):  
Alexander M. Polgar ◽  
Zachary M. Hudson
Keyword(s):  
Excited State ◽  
Delayed Fluorescence ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
State Behaviour

The use of thermally activated delayed fluorescence molecules as photosensitizers is covered with emphasis on strategies employed to control their excited state behaviour to suit a particular application.

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