Exciton and charge transfer processes within singlet fission micelles

Abstract

Multiexciton (ME) mechanisms hold great promise for enhancing energy conversion efficiency in optoelectronic and photochemical systems. In singlet fission (SF), the generation of two triplet excitons from a single photon provides a route to circumvent thermal energy losses and organic systems offer opportunities to modulate ME dynamics. However, the practical implementation of SF-based materials is hindered by poor triplet exciton mobility, interfacial recombination losses, and complex dynamics at heterogeneous interfaces. While studies of interfacial SF dynamics have demonstrated the potential for efficient charge and exciton transfer, experimental conditions and design of interfaces vary widely. To address this, we explore polymer-based self-assembled architectures as a tunable platform for studying mesoscale SF interfacial dynamics of (multi)exciton transfer, as well as electron and hole transfer. Specifically, we design amphiphilic block copolymers (BCPs) incorporating pendent tetracene moieties that self-assemble into micellar nanoparticles, placing the tetracenes in the amorphous core. These micelles provide a controlled environment to systematically introduce “dopants” to investigate interfacial dynamics. Importantly, the use of solvents within the micelle core can be also applied to impart polymer chain mobility.