Electrogenerated Chemiluminescence of Donor-Acceptor Molecules with Thermally Activated Delayed Fluorescence

• Published in: Angewandte Chemie International Edition Vol. 53; no. 27; pp. 6993 - 6996
• Main Authors: Ishimatsu, Ryoichi, Matsunami, Shigeyuki, Kasahara, Takashi, Mizuno, Jun, Edura, Tomohiko, Adachi, Chihaya, Nakano, Koji, Imato, Toshihiko
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.07.2014; WILEY‐VCH Verlag; Wiley Subscription Services, Inc
• Edition: International ed. in English
• Subjects: Activated; Chemiluminescence; electrochemiluminescence; Electrochemistry; Emittance; Energy gap; Fluorescence; kinetics; Photoluminescence; Polymer films; quantum yield; solvent effects; Statistics; Upconversion; Voltage; electrochemiluminescence; solvent effects; electrochemistry; kinetics; quantum yield
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.201402615

The electrochemistry and electrogenerated chemiluminescence (ECL) of four kinds of electron donor–acceptor molecules exhibiting thermally activated delayed fluorescence (TADF) is presented. TADF molecules can harvest light energy from the lowest triplet state by spin up‐conversion to the lowest singlet state because of small energy gap between these states. Intense green to red ECL is emitted from the TADF molecules by applying a square‐wave voltage. Remarkably, it is shown that the efficiency of ECL from one of the TADF molecule could reach about 50 %, which is comparable to its photoluminescence quantum yield. Donor–acceptor molecules with thermally activated delayed fluorescence (TADF) at room temperature can emit efficient electrogenerated chemiluminescence (ECL). Efficient spin up‐conversion from triplet to singlet excited states through thermal activation is required to break through the theoretical limitation according to spin statistics (25 % of the quantum yield of photoluminescence). The ECL efficiency one TADF molecule reached about 50 %.