0000000000336236
AUTHOR
Mathias Haase
Bio serves nano: biological light-harvesting complex as energy donor for semiconductor quantum dots.
Light-harvesting complex (LHCII) of the photosynthetic apparatus in plants is attached to type-II core-shell CdTe/CdSe/ZnS nanocrystals (quantum dots, QD) exhibiting an absorption band at 710 nm and carrying a dihydrolipoic acid coating for water solubility. LHCII stays functional upon binding to the QD surface and enhances the light utilization of the QDs significantly, similar to its light-harvesting function in photosynthesis. Electronic excitation energy transfer of about 50% efficiency is shown by donor (LHCII) fluorescence quenching as well as sensitized acceptor (QD) emission and corroborated by time-resolved fluorescence measurements. The energy transfer efficiency is commensurable …
Synthesis of Heterotelechelic α,ω Dye-Functionalized Polymer by the RAFT Process and Energy Transfer between the End Groups
The synthesis of a vinyl polymer with two different fluorescent dye end groups using reversible addition-fragmentation chain transfer (RAFT) polymerization is described. Use of a pentafluorophenyl (PFP) activated ester chain transfer agent (CTA) provided a polymer with an R end group that was reactive toward amines and a dithioester ω end group. The R PFP ester was amidated with Oregon Green Cadaverin. This did not harm the ω dithioester, which was subsequently aminolyzed with an excess of n-propylamine in the presence of Texas Red-2-sulfonamidoethyl methanethiosulfonate, resulting in a disulfide bond connecting the second dye to the polymer chain. Excess dyes and side products were removed…
Photoblinking and photobleaching of rylene diimide dyes.
We investigate photoblinking and photobleaching of perylene diimide (PDI) and its higher homologue terrylene diimide (TDI). Single molecule fluorescence trajectories of the dye molecules embedded in PMMA under ambient conditions exhibit "on"-"off" blinking in the time range from ms to s. Due to the limited statistics of individual trajectories we construct ensemble distributions of "on" and "off" times which follow power laws with similar power law coefficients (m(on) ≈ 1.18, m(off) ≈ 1.31). The blinking is attributed to reversible formation of radical cations which are presumably created by electron transfer from higher excited triplet states T(n) of the molecules to acceptor levels in the…
Probing the self-assembly and stability of oligohistidine based rod-like micelles by aggregation induced luminescence.
OA hybrid The synthesis and self-assembly of a new C2-symmetric oligohistidine amphiphile equipped with an aggregation induced emission luminophore is reported. We observe the formation of highly stable and ordered rod-like micelles in phosphate buffered saline, with a critical aggregation concentration below 200 nM. Aggregation induced emission of the luminophore confirms the high stability of the anisotropic assemblies in serum.