Direct Comparative Studies Revealing the Contribution of TADF Activity of Organic Emitters Towards Efficient Electrochemiluminescence

Jinliu Wei; Nairong Yang; Feiming Li; Shunyou Cai; Baohua Zhang; Zhixiong Cai

doi:10.1002/chem.202401036

Direct Comparative Studies Revealing the Contribution of TADF Activity of Organic Emitters Towards Efficient Electrochemiluminescence

Chemistry. 2024 May 14:e202401036. doi: 10.1002/chem.202401036. Online ahead of print.

Authors

Jinliu Wei¹, Nairong Yang¹, Feiming Li², Shunyou Cai², Baohua Zhang³, Zhixiong Cai⁴

Affiliations

¹ Minnan Normal University, College of Chemistry, Chemical Engineering and Environment, CHINA.
² Minnan Normal University, College of Chemistry, Chemical Engineering and Environment, NO.36, xianqianzhi Rd, 363000, Zhangzhou, CHINA.
³ Guangzhou University, School of Chemistry and Chemical Engineering, CHINA.
⁴ Minnan Normal University, NO.36, xianqianzhi Rd, 363000, Zhangzhou, CHINA.

PMID: 38742490
DOI: 10.1002/chem.202401036

Abstract

Electrochemiluminescence (ECL) featuring thermally activated delayed fluorescence (TADF) properties has attracted considerable interest, showcasing their potential for 100% exciton harvesting, which marks a significant advancement in the realm of organic ECL. However, the challenge of elucidating the precise contribution of TADF to the enhanced ECL efficiency arises due to the lack of comparative studies of organic compounds with or without efficient TADF properties. In this study, we present four carbazole-benzonitrile (Cz-BN) molecules possessing similar chemical structures and comparable exchange energy (ΔEST). Despite their comparable properties, these compounds exhibited varying TADF efficiencies, warranting a closer examination of their underlying structural and electronic characteristics governing the optical properties. Consequently, intense ECL emission was only observed from 4CzBN with a remarkable TADF efficiency, underscoring the substantial difference in the ECL signal among molecules with comparable ΔEST and similar spectral properties but varying TADF activity.

Keywords: Carbazole-benzonitrile; Electrochemiluminescence; RISC; Reorganization energy; TADF.