A Twist in Biphthalimide-Based Chromophores Enables Thermally Activated Delayed Fluorescence

Debnath, S and Ramkissoon, P and Vonder Haar, AL and Salzner, U and Smith, TA and Musser, AJ and Patil, S (2024) A Twist in Biphthalimide-Based Chromophores Enables Thermally Activated Delayed Fluorescence. In: Chemistry of Materials, 36 (9). 4607- 4615.

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Abstract

Thermally activated delayed fluorescence (TADF) emitters, which convert nonemissive triplets into emissive singlets, have garnered tremendous impetus as next-generation organic electroluminescent materials. Employing donor-acceptor (D-A) designs to produce intramolecular charge transfer (ICT) states is considered an attractive strategy to effectively reduce the singlet-triplet (�EST) gap, thereby enhancing reverse intersystem crossing (rISC) in TADF emitters. Herein, we report two ICT chromophores (BP-1TPA and BP-2TPA) utilizing a rational design strategy based on a twisted biphthalimide acceptor core integrated with varying triphenylamine donors. We accomplish efficient TADF emission with a high photoluminescence quantum yield (PLQY) of �80 at ambient conditions from poly(methyl methacrylate)-doped films of these chromophores. Twisting the acceptor core ensures the separation of natural transition orbitals, leading to small �EST and generates an intermediate triplet excited state to facilitate rISC. The present study, therefore, sheds light on how delayed fluorescence can be realized from a simple twisted phthalimide core by rational molecular engineering and enables new insights toward exploring the aromatic imide class of molecules as potential organic light-emitting materials. © 2024 American Chemical Society.

Item Type:	Journal Article
Publication:	Chemistry of Materials
Publisher:	American Chemical Society
Additional Information:	The copyright for this article belongs to American Chemical Society.
Keywords:	Charge transfer; Chromophores; Electroluminescence; Esters; Fluorescence; Organic light emitting diodes (OLED), Attractive strategies; Charge transfer state; Donor/acceptor; Electroluminescent materials; Intersystem crossing; Intra-molecular charge transfer; Intramolecular charge transfers; Organics; Singlet-triplet; Thermally activated delayed fluorescences, Excited states
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	19 Jul 2024 11:45
Last Modified:	19 Jul 2024 11:45
URI:	http://eprints.iisc.ac.in/id/eprint/84835

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