High Efficiency Liquid-crystalline Emitters through Multi-resonant Thermally Activated Delayed Fluorescence

Find Similar History 33 Claim Ownership Request Data Change Add Favourite

Title
High Efficiency Liquid-crystalline Emitters through Multi-resonant Thermally Activated Delayed Fluorescence

CoPED ID
f42bd3ea-9a0b-4d22-9b4c-7e6dd08e5c1d

Status
Active

Funder

Value
£204,031

Start Date
March 31, 2023

End Date
March 30, 2025

Description

More Like This


Orientational control of molecular order, anisotropic charge migration, operational lifetime, low cost, high efficiency and colour purity are essential for high-quality organic light emitting diodes (OLEDs). Luminescent discotic liquid crystals (LDLCs) showing columnar (Col) phases (formed by the self-organisation of disc-like, planar, fluorescent molecules decorated with peripheral alkyl chains) are candidate emitters for OLEDs. The increasing acceptance of columnar devices arises from their inherent properties such as anisotropy in conduction, control of molecular order, ease of processability and self-healing of structural defects. However, most LDLCs exhibit broad emission and their internal quantum efficiency is limited to 25% due to their inability to harvest electrogenerated triplets. This means that the external quantum efficiency of EL device has a theoretical maximum of 5-7%. Recently, thermally activated delayed fluorescence (TADF) has become a very attractive approach to emissive materials as they possess a small energy gap between the singlet and triplet excited states. This enables reverse inter-system crossing which in turn leads to the possibility of unit efficiency for emission. One approach to TADF is to use multiple resonance (MR-TADF), which has the advantage that the emission bands are extremely narrow (there are few vibrational effects) leading to very high colour purity. Further, they are realised in planar molecules and so form a perfect template for elaboration into discotic liquid crystals. The self-organisation inherent fluid liquid crystal phases leads to self-healing, high anisotropy of conductivity and exertion of control over the transition dipole moment, all of which will help to maximise the efficiency and performance of an OLED display. As such, this proposal seeks to realise a new paradigm in the design of efficient and effective emitters for OLEDs through the synthesis and characterisation of liquid crystalline MR-TADF materials.

Subjects by relevance
  1. Emissions
  2. Structure (properties)

Extracted key phrases
  1. High Efficiency Liquid
  2. Organisation inherent fluid liquid crystal phase
  3. Crystalline emitter
  4. Liquid crystalline mr
  5. Luminescent discotic liquid crystal
  6. Effective emitter
  7. High efficiency
  8. Candidate emitter
  9. High colour purity
  10. Internal quantum efficiency
  11. Orientational control
  12. High anisotropy
  13. Molecular order
  14. Resonant
  15. Multi

Related Pages

UKRI project entry

UK Project Locations