Abstract
Multi-resonant thermally activated delayed fluorescence (MR-TADF) materials have been widely investigated as emitters in organic light-emitting diodes (OLEDs) due to their bright and narrowband emission that results from their rigid structures and short-range charge transfer (SRCT) character of the emissive excited state. However, their planar geometry and relatively large singlet-triplet energy gap lead to, respectively, severe aggregation-caused quenching (ACQ) and slow reverse intersystem crossing (RISC). This thesis is partially centered on developing new MR-TADF emitters to solve these two problems.Using chiral compounds that can emit circularly polarized luminescence (CPL) is beneficial for their potential to increase the light out-coupling efficiency of OLEDs that use anti-glare filters. This thesis also investigates the design of chiral MR-TADF emitters, aiming to achieve bright, narrowband emission showing a strong CPL signal.
Chapter 1 introduces what is an OLED and how it works. The design of TADF emitters along with overviews of the development of heavy-atom-based MR-TADF emitters and chiral MR-TADF emitters are also discussed.
Chapter 2 presents the design of two MR-TADF emitters, TPPO-tBu-DiKTa and TPA-tBu-DiKTa, and the effect of twisted peripheral groups on the alleviation of ACQ and improvement of RISC.
Chapter 3 demonstrates two heavy-atom-based MR-TADF emitters, DiKTaSe and tBuCz-DiKTaSe, and the contribution of heavy atom effect to the TADF performance and efficiency roll-off in OLEDs.
Chapter 4 describes two chiral MR-TADF emitters tBuPh-BN and DPA-tBuPh-BN and their TADF and chiroptical properties.
Chapter 5 demonstrates the design of a propeller-shaped triple helicene DiKTa3 and explores its chiroptical properties through Density Functional Theory calculations.
Chapter 6 reports the design of a series of TADF polymers. Their TADF performance is investigated. The formation of chiral phase in polymer film through blending with chiral additives and their chiroptical properties are explored.
Chapter 7 includes the experimental methods used in this thesis.
Date of Award | 3 Jul 2025 |
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Original language | English |
Awarding Institution |
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Supervisor | Eli Zysman-Colman (Supervisor) |
Keywords
- Thermally activated delayed fluorescence
- Multi-resonant
- Organic light-emitting diodes
- Circularly polarized luminescence
- Chiral emitter
Access Status
- Full text embargoed until
- 23 Jan 2026