Disstacking of Phthalocyanine in Water by Poly(ethylene Oxide)

It was found that use of hydrophilic poly(ethylene oxide) (PEO) as a dispersion agent could disstack phthalocyanine (PC) in water and enhance its luminescence quantum yield. A combination of laser light scattering, UV−vis, and fluorescence spectroscopy was used to study the PEO/PC interaction. Our results revealed that, for a given weight concentration, long PEO chains were more effective than shorter ones to disstack PC into individual molecules. The PEO concentration dependence of UV−vis and fluorescence emission spectra showed that one long PEO chain ( M w ∼ 10 000 g/mol) is as effective as 25 short PEO chains ( M w ∼ 2000 g/mol).