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Time-resolved Photophysical Characterization of Triplet-harvesting Organic Compounds at an Oxygen-free Environment Using an iCCD Camera
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Vibration-Regulated Multi-State Long-Lived Emission from Star-Shaped Molecules
Yiran Li1,2, Glib V Baryshnikov3, Farhan Siddique3
1State Key Laboratory for Modification of Chemical Fiber and Polymer Materials, Key Lab of Science and Technology of Eco-Textile, Ministry of Education, College of Chemistry and Chemical Engineering, Donghua University, Shanghai, 201620, China.
Angewandte Chemie (International Ed. in English)
|October 8, 2022
Summary
Molecular vibration is key to tuning light emissions. Star-shaped molecules enable efficient thermally activated delayed fluorescence (TADF) and ultra-long room temperature phosphorescence (RTP) for advanced applications.
Area of Science:
- Photophysics
- Organic Electronics
- Materials Science
Background:
- Tuning photophysical properties like thermally activated delayed fluorescence (TADF) and room temperature phosphorescence (RTP) is crucial for advanced optoelectronic applications.
- Understanding the role of molecular vibration in controlling excited-state dynamics, particularly in multi-state emission processes, remains a significant challenge.
Purpose of the Study:
- To investigate how molecular vibration influences TADF and RTP emissions in star-shaped triphenylamine derivatives across different states (solution and solid).
- To elucidate the mechanisms by which molecular conformation and environment affect vibronic coupling and emission pathways.
Main Methods:
- Synthesis and characterization of star-shaped triphenylamine derivatives.
- Photophysical measurements including fluorescence and phosphorescence spectroscopy in solution and solid states.
- Analysis of molecular conformation and vibrational dynamics in different environments.
Main Results:
- Nonplanar, star-shaped molecular conformations promote vibrations in solution, facilitating vibronic coupling between T1 and T2 states for efficient TADF.
- Molecular dispersion and crystalline environments in the solid state enhance molecular vibrations, leading to more efficient TADF.
- Suppression of molecular vibration in doped polymer matrices inhibits TADF, enabling the observation of ultra-long RTP.
Conclusions:
- Molecular vibration is a critical parameter for controlling TADF and RTP emissions in organic molecules.
- Star-shaped triphenylamine derivatives offer a versatile platform for tuning emission properties through conformational and environmental control.
- These findings open avenues for developing novel materials for applications in information encryption, storage, and bioimaging.
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