Biomimetic zinc chlorinpoly(4-vinylpyridine) assemblies: doping level dependent emission absorption regimes

Ville Pale, Taru Nikkonen, Jaana Vapaavuori, Mauri Kostiainen, Jari Kavakka, Jorma Selin, Ilkka Tittonen, Juho Helaja

Research output: Contribution to journalArticleScientificpeer-review

22 Citations (Scopus)


To develop biomimetic dye–polymers for photonics, two different types of Zn chlorin–poly(4-vinylpyridine) (P4VP) assemblies were prepared by varying Zn pyro-pheophorbide a methylester (ZnPPME) and Zn 31-OH-pyro-pheophorbide a methylester (Zn-31-OH-PPME) doping levels. 1H NMR spectroscopy and diffusion ordered NMR spectroscopy (DOSY) studies revealed that a coordinative interaction between Zn chlorin and P4VP was predominant in solution (d5-nitrobenzene). Small angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) characterization of bulk samples of polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) doped with variable amounts of Zn chlorin showed that the pigment doping transformed the native cylindrical block copolymer nanostructures to lamellar morphologies. The result indicates that the pyridine moiety–Zn chlorin coordination is stronger than the aggregation tendency between the pigment molecules even in the solid state. UV-Vis absorption spectroscopy studies of a Zn chlorin–P4VP thin film showed characteristic monomeric chlorin spectra, while steady-state fluorescence spectroscopy displayed quenching of fluorescence and time-resolved studies indicated shortening of fluorescence lifetimes with an increasing chlorin doping level. Notably, time-resolved fluorescence spectroscopy revealed that the lifetime decay changed from monoexponential to biexponential above 0.5 wt% (ca. 0.001 equiv.) loadings. The Förster analysis implies that excitonic chlorin–chlorin interactions are observed in the thin films when the distance between the pigment molecules is approximately 50 Å. The Zn chlorin–P4VP solid films emit strongly up to 1 wt% (ca. 0.002 equiv.) doping level above which the chlorin–chlorin interactions start to linearly dominate with an increase of doping level, while with 10 wt% (ca. 0.02 equiv.) loading less than 10% of fluorescence remains. Doping levels up to 300 wt% (0.5 equiv.) can be used in absorbing materials without the formation of...
Original languageEnglish
Pages (from-to)2166-2173
Number of pages8
JournalJournal of Materials Chemistry C
Issue number11
Publication statusPublished - 29 Jan 2013
MoE publication typeA1 Journal article-refereed


  • absorption
  • dye-doped polymeric materials
  • fluorescence
  • förster theory
  • poly(4-vinylpyridine)
  • zinc chlorin

Fingerprint Dive into the research topics of 'Biomimetic zinc chlorinpoly(4-vinylpyridine) assemblies: doping level dependent emission absorption regimes'. Together they form a unique fingerprint.

Cite this