Crystal growth and molecular orientation of tetraphenylmetalporphyrin vapor-deposited on poly(tetrafluoroethylene) friction-transferred layers

Three tetraphenylmetalporphyrins (VOTPP, FeClTPP and MgTPP · H2O) were vapor-deposited on a friction-transferred poly(tetrafluoroethylene) (PTFE) layer. Thin layers of PTFE used as a substrate were transferred on glass supports by the friction deposition. The PTFE layer formed an uniaxially oriented thin film. Porphyrin films deposited on a friction-transferred PTFE layer were composed of rectangular or trapezoid crystals. The edges of crystals crossed at ±26° the (001) direction of the substrate PTFE crystal. Orientation relations between the deposited porphyrin and the substrate PTFE were (001)porphyrin∥(100)PTFE and [100]porphyrin < [001]PTFE = ±26°. The oriented growth of porphyrins on a friction-transferred PTFE layer was explained as point-on-line coincidence. The photoelectrochemical properties of a randomly-oriented and an oriented films were investigated in cells of the configuration ITO/porphyrin/I3−, I−/Pt. Enhanced photocurrent quantum yield was obtained by epitaxial orientation.