Extended star graph as a light-harvesting-complex prototype: Excitonic absorption speedup by peripheral energy defect...

Area of Science:

• Quantum dynamics
• Molecular nanonetworks
• Exciton physics

Background:

• Studying photoexcitation dynamics in extended networks is crucial for energy harvesting.
• Understanding energy absorption at the core of star networks is key.
• Peripheral defects can influence energy transfer processes.

Purpose of the Study:

• Investigate the impact of peripheral defects on photoexcitation energy absorption in star networks.
• Determine optimal defect parameters for enhanced energy absorption.
• Elucidate the underlying mechanisms responsible for absorption speedup.

Main Methods:

• Numerical simulations of quantum dynamics.
• Analysis of photoexcitation distribution and energy transfer.
• Analytical modeling of excitonic eigenstate hybridization.

Main Results:

• An optimal energy defect (Δ*) exists, dependent on network architecture (N_B branches, L_B length).
• A significant speedup in energy absorption occurs for L_B ≤ L_B* (≈12.5/ln(N_B)).
• This speedup arises from the hybridization of upper-band excitonic eigenstates.

Conclusions:

• Peripheral defects can be engineered to control and enhance energy absorption in star networks.
• The observed speedup is linked to specific network structural conditions and quantum effects.
• These findings provide design principles for efficient molecular nanonetworks for photoexcitation absorption.