April 2001 Ž . Materials Letters 48 2001 144–150 www.elsevier.comrlocatermatlet Electrical properties of conducting polypyrrole films functionalized with phthalocyanine S. Radhakrishnan ) , S.D. Deshpande Polymer Science and Engineering, Council of Scientific and Industrial Research, National Chemical Laboratory, Pune 411 008, India Received 12 December 1999; received in revised form 13 August 2000; accepted 18 August 2000 Abstract Polypyrrole films containing phthalocyanine were deposited by direct electrochemical deposition method using mixed Ž . Ž . solvent system NMP:H O with H SO 0.1 M . The films obtained were characterized by conventional techniques such as 2 2 4 Ž . FT-IR and UV–VIS, which confirmed the incorporation of phthalocyanine. The presence of Cu 2p core level peak in the ESCA studies also confirmed the incorporation of phthalocyanine in these films. The electrical conductivity was found to Ž increase with the increase of phthalocyanine concentration in the electrolyte. Even for a moderate increase of CuPc from 1.0 . to 2.0 mol% in the PPy films, there is a drop in activation energy from 0.133 to 0.08 eV. Sensitivity measurements show that the CuPc containing PPy films are selectively more sensitive to the nitrogen dioxide vapours. The C– V studies carried out on these films under illumination show that the photochemical response in electrochemical mode increases due to the presence of phthalocyanine. The cathodic peak at y700 mV, which is associated with the phthalocyanine, becomes prominent under illumination due to photogenerated carriers. q 2001 Elsevier Science B.V. All rights reserved. Keywords: Polypyrrole; Phthalocyanine; UV–VIS 1. Introduction Recently, a great deal of interest has been given to the electrochemical preparation of a number of polypyrroles, utilizing a variety of ionic complexes and polyelectrolytes as the electrolytes during elec- tropolymerization which serve as charge-balancing ) Corresponding author. Tel.: q 91-212-331-453; fax: q 91-212- 334-761. Ž . E-mail address: srr@ems.ncl.res.in S. Radhakrishnan . dopant anions. This has led to a new class of multi- component materials with controllable electrical, me- chanical, electrochemical, catalytic ion-binding and ion-releasing properties. These approaches include the preparation of PPy containing Ru-bipyridine com- plexes, naphthoquinone and benzoquinone groups wx 1, complexes with metallotetraphenyl–porphyrin wx wx 2 and phthalocyanines complexes, etc. 3 . Metal phthalocyanines complexes have been wx widely studied for their electrochemical 4 , electro- wx wx wx catalytic 5 , photocatalytic 6 , non-linear optical 7 wx and photo electrochemical properties 8 . Polypyr- role, containing metal phthalocyanine complexes, is thus a potential electro-switchable, multifunctional 00167-577Xr01r$ - see front matter q 2001 Elsevier Science B.V. All rights reserved. Ž . PII: S0167-577X 00 00294-9