Energy Transfer in Aqueous Light Harvesting Antennae Based on Brush-like Inter-Conjugated Polyelectrolyte Complexes
- Univ. of California, Santa Cruz, CA (United States)
- Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). Molecular Foundry
Conjugated polyelectrolytes (CPEs) have the potential to serve as building blocks of artificial light-harvesting systems. This is primarily due to their delocalized electronic states and potential for hierarchical self-assembly. We showed previously that inter-CPE complexes composed of oppositely charged exciton-donor and exciton-acceptor CPEs displayed efficient electronic energy transfer. However, near ionic charge equivalence, complexed CPE chains become net-neutral and thus experience a precipitous drop in aqueous solubility. To increase the stability and to rationally manipulate the phase behavior of inter-CPE complexes, we synthesized a series of highly water-soluble exciton-donor CPEs composed of alternating ionic and polar nonionic fluorene monomers. The nonionic monomer contained oligo(ethyleneglycol) sidechains of variable length. We then formed exciton donor-acceptor complexes and investigated their relative energy transfer efficiencies in the presence of a fixed exciton-acceptor CPE. We find that, even when the polar nonionic sidechains become quite long (nine ethyleneglycol units), the energy transfer efficiency is hardly affected so long as the inter-CPE network retains a net polyelectrolyte charge. However, near the onset of spontaneous phase separation, we observe a clear influence of the length of the oligo(ethyleneglycol) sidechains on the photophysics of the complex. Our results have implications for the use of polyelectrolyte phase separation to produce aqueous light-harvesting soft materials.
- Research Organization:
- Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES), Materials Sciences & Engineering Division
- Grant/Contract Number:
- AC02-05CH11231; AC02-76SF00515
- OSTI ID:
- 1987301
- Journal Information:
- Macromolecules, Vol. 55, Issue 23; ISSN 0024-9297
- Publisher:
- American Chemical SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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