Semiconductor Electrodes. 50. Effect of Mode of Illumination and Doping on Photoelectrochemical Behavior of Phthalocyanine Films.

摘要

The behavior of photoelectrochemical (PED) cells composed of Sno2 or Pt electrodes with coatings of different phthalocyanines (Pc) -H2PC, ZnPc, MgPc, (CuPc, InPc) 1 was investigated. Spectral sensitization at the Sn02/Pc interface leads to photooxidation currents, while efficient photoreduction occurs at the Pc/solution interface through bulk generation of charge carriers. The presence of both anodic and cathodic photocurrents leads to different net photocurrent responses for back and front side illumination, especially with thicker films. The efficiency of the reduction process was sensitive to the potential of the redox couple in solution and maximized when E redox was about 0.37V for N2Pc, ZnPc and -MgPc. A dramatic improvement of the photoelectrochemical behavior of the coating results from doping with an electron acceptor (e.g.,o-chloranil) and quantum yields as high a s 4.6% were measured for Pt/H2Pc electrodes.