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2,7-Substituted hexafluoroheterofluorenes as potential building blocks for electron transporting materials
Katharine Geramita1, Jennifer McBee, T Don Tilley
1Department of Chemistry, University of California at Berkeley, Berkeley, California 94720, USA.
New hexafluoro-9-heterofluorenes were synthesized for potential use in electron transport materials. Their low LUMO energy levels and tunable optical properties make them promising building blocks for advanced electronic applications.
Area of Science:
- Organic Chemistry
- Materials Science
- Photophysics
Background:
- Hexafluoro-9-heterofluorenes are investigated for their electronic properties.
- Electron transport materials are crucial for organic electronics.
Purpose of the Study:
- Synthesize novel 2,7-substituted hexafluoro-9-heterofluorenes.
- Evaluate their potential as building blocks for electron transport materials.
- Characterize their optical and electronic properties.
Main Methods:
- Nucleophilic aromatic substitution (S(N)Ar(F)) reactions.
- UV-vis spectroscopy for HOMO-LUMO energy gap determination.
- Photoluminescence spectroscopy for emission spectra.
- Differential pulse voltammetry for LUMO energy level determination.
- Single-crystal X-ray analysis for structural insights.
Main Results:
- Successful synthesis of 2,7-substituted hexafluoro-9-heterofluorenes.
- HOMO-LUMO energy gaps ranged from 3.0 to 3.9 eV.
- Photoluminescence emissions observed from 365 to 420 nm (UV to violet/blue).
- LUMO energy levels determined to be between -2.7 and -3.3 eV.
- Quantum yields approached unity for di(phenylethynyl) derivatives.
- X-ray analysis revealed cofacial packing with short intermolecular distances.
Conclusions:
- The synthesized compounds exhibit properties suitable for electron transport applications.
- Tunable optical and electronic characteristics offer versatility in material design.
- Low LUMO levels indicate good electron accepting capabilities.
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