Department of Applied Chemistry, Graduate School of Engineering Osaka University MINAKATA Lab. Synthetic Organic Chemistry Research Group

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論文 Publication List at MINAKATA Lab.

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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"
Takumi Hosono, Nicolas Oliveira Decarli, Paola Zimmermann Crocomo, Tsuyoshi Goya, Leonardo Evaristo de Sousa, Norimitsu Tohnai, Satoshi Minakata, Piotr de Silva*, Przemyslaw Data*, and Youhei Takeda*
J. Mater. Chem. C Advance Article. DOI:10.1039/D1TC05730H

*Invited as a part of the themed collection "Materials for thermally activated delayed fluorescence and/or triplet fusion upconversion"!

Abstract: Exploring the design principle for switching between thermally activated delayed fluorescence (TADF) and room temperature phosphorescence (RTP) is a fundamentally important research to develop triplet-mediated photofunctional organic materials. Herein systematic studies on the regioisomeric and substituent effects in a twisted donor–acceptor–donor (D–A–D) molecular scaffold (A = dibenzo[a,j]phenazine; D = dihydrophenazasiline) on the fate of its excited state have been performed. The study revealed that regioisomerism clearly affects the emission behavior of the D–A–D compounds. Moreover, distinct differences in TADF, dual TADF & RTP, and dual RTP were observed, depending on the host used. Furthermore, organic light-emitting diodes (OLEDs) fabricated with the developed emitters achieved high external quantum efficiencies (EQEs) of up to 7.4% for RTP-based OLEDs.

“A New Entry to Purely Organic Thermally Activated Delayed Fluorescence Emitters Based on Pyrido[2,3-b]pyrazine–Dihydrophenazasilines Donor–Acceptor Dyad"
Tsuyoshi Goya, Paola Zimmermann Crocomo, Takumi Hosono, Satoshi Minakata, Leonardo Evaristo de Sousa, Piotr de Silva*, Przemyslaw Data*, and Youhei Takeda*
Asian J. Org. Chem. Accepted Article. DOI:10.1002/ajoc.202100780 (Published as part of the 10th Anniversary Collection-invitaion only!)

*Open-Access Article!
*Invited as a part of the Special Collection "10th Anniversay Collection"!

Abstract: A new family of thermally activated delayed fluorescence (TADF) emitters based on a twisted donor–acceptor (D–A) dyad scaffold comprising of dihydrophenazasiline (D) and pyrido[2,3- b ]pyrazine (A) has been developed, and their properties have been investigated. Time-resolved spectroscopic analysis in matrices revealed the detailed photophysical properties of the D–A compounds. These D–A compounds serve as the emitter for organic light-emitting diodes (OLEDs), showing a moderate external quantum efficiency (EQE) up to 9% in CBP matrix. Furthermore, theoretical calculations uncovered the excited states nature of the developed TADF emitters.

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