Exciton Transfer Between Extended Electronic States in Conjugated Inter-Polyelectrolyte Complexes

Journal Article · Tue Jan 30 00:00:00 EST 2024 · ACS Applied Materials and Interfaces

DOI:https://doi.org/10.1021/acsami.3c14657· OSTI ID:2433959

Richards, Rachael ^[1]; Song, Yuqi ^[2]; O’Connor, Luke ^[2]; Wang, Xiao ^[1]; Dailing, Eric A. ^[3]; Bragg, Arthur E. ^[2]; Ayzner, Alexander L. ^[1]

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1. Univ. of California, Santa Cruz, CA (United States)
2. Johns Hopkins Univ., Baltimore, MD (United States)
3. Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). Molecular Foundry

Artificial light harvesting, a process that involves converting sunlight into chemical potential energy, is considered to be a promising part of the overall solution to address urgent global energy challenges. Conjugated polyelectrolyte complexes (CPECs) are particularly attractive for this purpose due to their extended electronic states, tunable assembly thermodynamics, and sensitivity to their local environment. Importantly, ionically assembled complexes of conjugated polyelectrolytes can act as efficient donor-acceptor pairs for electronic energy transfer (EET). However, to be of use in material applications, we must understand how modifying the chemical structure of the CPE backbone alters the EET rate beyond spectral overlap considerations. In this report we investigate the dependence of the EET efficiency and rate on the electronic structure and excitonic wave function of the CPE backbone. To do so, we synthesized a series of alternating copolymers where the electronic states are systematically altered by introducing comonomers with electron withdrawing and electron-rich character while keeping the linear ionic charge density nearly fixed. We find evidence that the excitonic coupling may be significantly affected by the exciton delocalization radius, in accordance with analytical models based on the line-dipole approximation and quantum chemistry calculations. Our results imply that care should be taken when selecting CPE components for optimal CPEC EET. These results have implications for using CPECs as key components in water-based light-harvesting materials, either as standalone assemblies or as adsorbates on nanoparticles and thin films.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL)
• Sponsoring Organization: National Institute of General Medical Sciences (NIGMS); National Institutes of Health (NIH); USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF)
• Grant/Contract Number: AC02-05CH11231; AC02-76SF00515
• OSTI ID: 2433959
• Journal Information: ACS Applied Materials and Interfaces, Journal Name: ACS Applied Materials and Interfaces Journal Issue: 16 Vol. 16; ISSN 1944-8244
• Publisher: American Chemical Society (ACS)
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
conjugated polyelectrolyte
energy transfer
exciton
polyelectrolyte complex
self-assembly