Abstract: The SnO₂ electrodes were modified by phthalocyanine with different length of alkyl substitutes (ZnPcCH₂n+1,n=3,9,12,16) using L-B method. The formation of a stable monolayer on water and the characterics of phase transition were observed. The photovoltaic behaviours and adsorption spectra of monolayer assemblies were determined. The results showed that L-B films of ZnPcC₃H₇(i) which has horter chain of alkyl substitutes exhibit larger transfer ratio and better photovoltaic effects.

Key words: L-B film, phthalocyanine compound, open-circuit photovoltage, short-circuit photocurrent