Journal of Physical Studies 2(4), 476–482 (1998) DOI: https://doi.org/10.30970/jps.02.476 PHOTOPROCESSES IN LANGMUIR–BLODGETT VANADYLPHTHALOCYANINE FILMS

P. O. Kondratenko, K. V. Storozhenko
Institute of Physics of the National Academy of Sciences of Ukraine,
46 Nauky Pr., Kyiv, UA–252650, Ukraine

Physical and photochemical processes in the Langmuir–Blodgett films (LBF) and solutions of vanadylphthalocyanine (VOPc) were investigated. The solvents influence on both the spectral characteristics and associations efficiency of VOPc molecules was observed: solvents polarity increasing cause decreasing of both the absorption bands width and associations grade. Spectral bands splitting exists due to weak interaction between $π$–MO and substituents. It was shown that the excitation of VOPc molecule (in solutions and LBF) to high energy states causes its photodissociation by predissociations mechanism mainly. Predissociation is realized by excitations relaxation from $S_n(ππ^{*})$ to $πσ^{*}$–state ($σ^{*}$–mo is localised on the bridge C–N–band). The association between VOPc molecules and the ones or both water molecules and photodissociations product cause decreasing of photodissociations quantum yield.

ps pdf