Unquenched fluorescence lifetime for β-phenylthio substituted zinc phthalocyanine upon conjugation to gold nanoparticles

Photoinduced processes in phthalocyanine-functionalized gold nanoparticles have been investigated by spectroscopic measurements. The zinc phthalocyanine used contained four phenylthio peripheral substituents (ZnPc(SPh)4). The conjugates formed are represented as ZnPc(SPh)4–AuNP. The absorption spectrum of the ZnPc(SPh)4–AuNP shows a broadening of the phthalocyanine Q-band absorption, probably due to a tight packing of the phthalocyanines on the gold nanoparticle surface. For the attached phthalocyanines, the two fluorescence lifetimes obtained by time-correlated single photon counting (TCSPC) were determined to be both longer and shorter than that of the free Pc. The fluorescence lifetimes were resolved using time resolved fluorescence spectroscopy (TRES).

Photoinduced processes in phthalocyanine-functionalized gold nanoparticles have been investigated by spectroscopic measurements. The phthalocyanine used contained four phenylthio at the peripheral positions. An increase in fluorescence lifetime was observed for a phthalocyanine conjugated to AuNPs which is novel for small gold nanoparticles.Figure optionsDownload as PowerPoint slideHighlights
► Gold nanoparticles are functionalized with a zinc phthalocyanine.
► The conjugates are characterized by fluorescence techniques.
► The gold nanoparticles enhanced the fluorescence of phthalocyanines.