Effects of hole transport layer on photoelectrochemical responses from polythiophene-porphyrin composite polymer electrode

The effect of a hole transport layer on the photoelectrochemical responses from an organic solar cell consisting of a composite polymer film of 5,10,15,20-tetra(3-thienyl)-21H,23H-porphyrin and polythiophene was investigated. The polyalkylthiophene layer that was inserted between the above-described photoactive polymer film and a transparent electrode acted as the hole transport layer. This layer remarkably suppressed the recombination of separated charge carriers generated in the composite polymer film and substantially improved both photocurrent and conversion efficiencies.