Quantifying Exciton Transport in Singlet Fission Diblock Copolymers

Area of Science:

• Organic electronics
• Photophysics
• Polymer science

Background:

• Singlet fission (SF) is an exciton multiplication process in organic chromophores with potential for efficient optoelectronic devices.
• Understanding multiscale electronic interactions, including interchromophore dynamics and exciton diffusion, is crucial for SF device architectures.
• Block copolymers (BCPs) offer tunable control over multiscale interactions, but SF dynamics within them remain poorly understood.

Purpose of the Study:

• To investigate singlet fission dynamics in designed diblock copolymers.
• To understand exciton transport and interfacial energy transfer in multichromophore systems.
• To correlate energy transfer kinetics and yields with BCP block lengths.

Main Methods:

• Design of diblock copolymers with pendent pentacene and tetracene chromophores.
• Utilizing time-resolved optical spectroscopy to quantify energy transfer processes.
• Analysis of singlet and triplet energy transfer across the pentacene-tetracene interface.

Main Results:

• Quantification of singlet and triplet energy transfer yields across the BCP interface.
• Demonstration of exciton transport driven by energy offset along the BCP chain.
• Correlation of energy transfer timescales and yields with BCP block lengths.

Conclusions:

• Designed BCPs enable quantification of energy transfer at critical length scales.
• Insights into exciton transport between molecular dimers and bulk systems were gained.
• This modular approach provides a platform for understanding and optimizing SF in macromolecular systems.