Structure and photoelectric properties of tetrakis(4-N-hexadecylpyridiniumyl)porphyrin/anthraquinone LB films

Using a 1 : 1 tetrakis(4-N-hexadecylpyridiniumyl)porphyrin/anthraquinone (TC16PyP(4)/AnQ) mixture as film-forming material, the structure and properties of TC16PyP(4)/AnQ mixed monolayers or LB films were studied by pi-A isotherms, UV-VIS absorption spectra, and low-angle X-ray diffraction (LAXD). The experimental results indicate that the TC16PyP(4)/AnQ mixture has good film-forming properties at the air/water interface. The TC16PyP(4)/AnQ mixed monolayer can be transferred to glass, quartz or SnO2 optically transparent electrode (OTE) substrates. Most AnQ molecules are incorporated into the cavities between the long alkyl chains of TC16PyP(4) molecules in the mixed monolayer or in LB films. The TC16PyP(4)/AnQ mixed LB films can be regarded as a two-dimensional host-guest system and show good stability and periodicity. The photovoltaic behaviour of an electrochemical cell containing a TC16PyP(4)/AnQ LB film, deposited on an SnO2 OTE, was also investigated. The photocurrent and photovoltage are apparently lower than those for the photocell of pure TC16PyP(4) LB films due to the incorporation of AnQ.