Photocurrent generation of PEG substituted phthalocyanine polymers

Phthalocyanine polymers substituted with polyethylene glycol (PEG), PPEGPc, were synthesized and characterized by photo electrochemistry. To examine the effects of the ethyleneoxy group on the photoconductivity of phthalocyanine polymers, different PEGs of Mw 164 - 750 were introduced by the esterification of the phthalocyanine polymer. A thin film of phthalocyanine polymer was coated onto a conductive ITO glass using a mixture of soluble PPEGPc in DMF. Phthalocyanine polymers substituted with polyethylene glycol showed a higher photocurrent generation compared to that of an unsubstituted polymer, suggesting that the PEG units facilitate transport of generated charge carriers. Maximum photocurrent was obtained from a PEG of Mw550. Photocurrent generation was highly dependent on the PEG chain length, indicating that ethyleneoxy groups in PEG participate in charge transport. The morphology of the polymer film was investigated on to correlate the domain structure of the PPEGPc with the charge transport property.