Highly efficient circularly polarized organic luminogens with a large dissymmetry factor of circularly polarized luminescence characteristics

2016 Fiscal Year Final Research Report

• Project/Area Number: 26620165
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Organic and hybrid materials
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Hirata Shuzo 東京工業大学, 物質理工学院, 助教 (20552227)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: Delayed fluorescence / TADF / CPL / Chirality / OLED / EL display / Display / Contrast

Outline of Final Research Achievements

Three kinds of metal-free aromatic compounds (CPDF1-3) with a chiral carbon sandwiched between a donor moiety and an acceptor moiety were designed. They showed thermally activated delayed fluorescence (TADF) as well as circularly polarized luminescence (CPL) characteristics. (R)-CPDF3 and (S)-CPDF3 showed CPL with a dissymmetry factor of 4×10-4 in toluene solution. CPDF3 doped into π-conjugated host with large energy of the lowest triplet excited state displayed a photoluminescence quantum yield of 99%. An electroluminescence (EL) device having a 30 wt% CPDF3 doped π-conjugated host as an emitting layer showed an external EL quantum yield of 9.5%. With increasing the concentration of (R)-CPDF3 and (S)-CPDF3 in the emitting layer, intermolecular charge transfer transition largely contributed to TADF, causing a disappearance of CPL characteristics from the devices.

Free Research Field

有機光エレクトロニクス