C-N Bond Rotation Controls Photoinduced Electron Transfer in an Aminostyrene-Stilbene Donor-Acceptor System

Area of Science:

• Photochemistry
• Organic Electronics
• Computational Chemistry

Background:

• Donor-acceptor molecules are crucial for organic optoelectronics.
• Understanding excited-state dynamics is key to designing efficient materials.

Purpose of the Study:

• Investigate energy and electron transfer mechanisms in a model aminostyrene-stilbene dimer.
• Clarify the origins of dual emission and photoinduced electron transfer.

Main Methods:

• Time-dependent density functional theory (TD-DFT) calculations.
• Potential energy surface scans along C-N bond torsional angles.

Main Results:

• Identified local excitations and a charge-transfer (CT) excited state.
• Discovered a twisted intramolecular charge transfer (TICT) state and a conical intersection between S2 and S1 states.
• Located a thermally accessible, emissive V-shaped CT structure responsible for observed emission.

Conclusions:

• Conical intersection dominates electron transfer dynamics.
• C-N bond rotation barrier controls transfer efficiency.
• Findings provide a synthetic route for controlling emissive properties and electron transfer in organic optoelectronic materials.