A review of 9, 9-Dimethyl-9, 10-dihydroacridine (DMAC) derivatives as thermally activated delayed fluorescence emitters in OLED applications

Abstract

Thermally Activated Delayed Fluorescence (TADF) has emerged as a game changer in the field of organic light-emitting diodes (OLEDs). By cleverly harnessing both singlet and triplet excitons, TADF offers a compelling pathway to achieve high internal quantum efficiencies (IQEs) without relying on expensive and often problematic rare-earth metals used in phosphorescent materials. This review focuses on TADF emitters utilizing at least one 9,9-Dimethyl-9,10-dihydroacridine (DMAC) unit as a donor and is structured according to different acceptor building blocks, including, triazines, pyrimidines, sulfones, carbonyls, anthraquinones, pyridines, borons, and others, along with material design strategies, device performance, and future prospects. The incorporation of acridine derivatives into OLED materials can enhance the efficiency and stability of light emission, making them promising candidates for next-generation display technologies. The distinctive planar structure of acridine allows for effective π-π stacking, facilitating charge transport and exciton formation in the organic layers. Furthermore, acridine's ability to emit light in a wide range of colors (red, green, blue, and white) is particularly valuable. Herein, the recent developments of DMAC derivatives is methodically summarized, that structure–property relationships focused on two fundamental factors of interest for TADF emitters, including, frontier molecular orbitals separation and minimal singlet–triplet energy gap (ΔE_ST) and OLED applications. It is anticipated that this review will provide a comprehensive overview of the role of this acridine analog in advancing OLED materials and present exciting possibilities for both scientific research and commercial applications.