Thermally Activated Delayed Fluorescence in an Organic Cocrystal: Narrowing the Singlet-Triplet Energy Gap via Charge Transfer.
Lingjie SunWeijie HuaYang LiuGuang-Jun TianMingxi ChenMingxing ChenFangxu YangShufeng WangXiaotao ZhangYi LuoWenping HuPublished in: Angewandte Chemie (International ed. in English) (2019)
Harvesting non-emissive spin-triplet charge-transfer (CT) excitons of organic semiconductors is fundamentally important for increasing the operation efficiency of future devices. Here we observe thermally activated delayed fluorescence (TADF) in a 1:2 CT cocrystal of trans-1,2-diphenylethylene (TSB) and 1,2,4,5-tetracyanobenzene (TCNB). This cocrystal system is characterized by absorption spectroscopy, variable-temperature steady-state and time-resolved photoluminescence spectroscopy, single-crystal X-ray diffraction, and first-principles calculations. These data reveal that intermolecular CT in cocrystal narrows the singlet-triplet energy gap and therefore facilitates reverse intersystem crossing (RISC) for TADF. These findings open up a new way for the future design and development of novel TADF materials.
Keyphrases
- energy transfer
- dual energy
- image quality
- quantum dots
- computed tomography
- single molecule
- contrast enhanced
- high resolution
- current status
- density functional theory
- positron emission tomography
- solid state
- minimally invasive
- magnetic resonance
- light emitting
- molecular dynamics
- water soluble
- gene expression
- machine learning
- dna methylation
- pet ct