24-copper octakis (octyloxy) phthalocyanine (CuPcOC 8 ) thin films deposited at room temperature have exhibited a change in their surface morphology with the post deposition annealing temperature under normal atmosphere.These films have been characterised by optical absorption also. SEM images have shown densely packed nano particles and nano-rod like structures on the substrates annealed at different temperatures. The optical transition was found to be direct allowed and the direct energy gap changed with the annealing temperature. The results of optical and surface morphological studies on CuPcOC 8 have been discussed.

Vacuum deposited 2,3,9,10,16,17,23,24-octakis (octyloxy) phthalocyanine (H2PcOC8) thin films on glass substrates have exhibited a change on their surface morphology with the post deposition annealing temperature under normal atmosphere. These films have been characterized by optical absorptions and Scanning Electron Microscopy. SEM images also have shown nano-rod like structures for the samples annealed at different temperatures. The variation of optical band gap with annealing temperature is determined. The direct and allowed optical band gap energy has been evaluated from the α2versus hυ plots. The electrical conductivity of the films at various heat treated samples are also studied. The activation energies are determined from the Arrhenius plots of lnσ versus 1000/T . It shows variation with the annealing temperature.

New generation electronic and optoelectronic devices require thin films of new materials with specific properties. Such properties are discovered by the complex combination of many physical factors as well as the chemical nature of the starting material. Especially highly delocalized conjugated organic systems such as substituted as well as unsubstituted metal phthalocyanines (MPc's) represent the promising candidates in (opto) electronic applications, since appropriate substitutions of the phthalocyanine skeleton can result in different electronic and transport thin film properties [1][2][3][4] . Also the electrical and optical properties of phthalocyanines are determined by a central metal ion and side groups 5 . Due to their high thermal and chemical stability, they have become an important material widely used in optical and electronic devices technology [6][7][8] . They are used, for instance, to fabricate light emitting diodes, field effect transistors and solar cells 9 . They find applications in the field of gas sensors 10,11 and photodynamic therapy of cancer [11][12][13] . Metal free and metal-containing phthalocyanine compounds with alkyl, alkoxy, thioalkoxy, ethyleneoxy chains have since been synthesized 14,15 . Moreover, amongst the two possible peripheral octa-substitution patterns,ie;the lateral positions(