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Transient Absorption Spectroscopy Probes Ultrafast Excited-State Dynamics in D-π-D Chalcone Derivatives
Suman Dhami1, Yogesh Kumar1, Panaha1
1Department of Chemistry, Indian Institute of Technology Roorkee, Haridwar, Uttarakhand, India.
Summary
New chalcone derivatives show tunable excited-state dynamics. Symmetric molecules form long-lived triplet states, while asymmetric ones exhibit radiative decay, guiding optoelectronic material design.
Area of Science:
- Organic Chemistry
- Photophysics
- Materials Science
Background:
- Chalcone derivatives are π-conjugated systems with tunable electronic properties.
- Structure-property relationships in chalcones are well-defined, making them attractive for optoelectronics.
Purpose of the Study:
- To design, synthesize, and characterize novel D-π-D chalcone derivatives (IITR-9, IITR-10, IITR-11).
- To investigate the excited-state dynamics and relaxation pathways of these derivatives.
- To understand how electron-donating groups influence excited-state behavior and potential optoelectronic applications.
Main Methods:
- Synthesis and characterization of three D-π-D chalcone derivatives.
- Femtosecond transient absorption spectroscopy (TAS) to study excited-state dynamics.
- Solvatochromic measurements and theoretical calculations to confirm intramolecular charge-transfer (ICT) states.
Main Results:
- All synthesized chalcones exhibited an intramolecular charge-transfer (ICT) state.
- Symmetric derivatives (IITR-9, IITR-10) showed long-lived excited-state absorption (>8 ns), indicating triplet-state formation.
- The asymmetric derivative (IITR-11) displayed radiative relaxation from the ICT state within 3.0 ± 0.2 ns.
Conclusions:
- The nature and arrangement of electron-donating groups critically control excited-state pathways in chalcone derivatives.
- This control influences charge-transfer (CT) and triplet state formation, crucial for optoelectronic applications.
- The findings provide insights for designing advanced chalcone-based optoelectronic materials.
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