Investigation of the photoelectrochemistry of C-60 and its pyrrolidine derivatives by monolayer-modified SnO2 electrodes

A monolayer of a C-60 mixture with arachidic acid (1:1) and C-60-pyrrolidine derivatives [C-60(C(3)H(6)NR); R = H (1), C6H5 (2), o-C6H4NO2 (3), and o-C(6)H(4)NMe(2) (4)] were successfully obtained at the air/water interface and deposited onto solid substrates with transfer ratios of about 0.90 +/- 0.05 at 30 mN . m(-1) by the Langmuir-Blodgett (LB) technique. The photoelectrochemical investigation of these compounds on SnO2 electrodes was carried out. The photocurrent was determined under nitrogen atmosphere because oxygen can suppress the photocurrents. Results showed that electrons flow from the electrolyte through LB film to SnO2 and a chemical energy conversion occurs together with the photoelectric conversion. Positive bias voltage, electron donor, the incident light intensity, and the electron-repulsion groups in the derivatives are beneficial factors for generating higher photocurrent. The quantum yields vary from 0.015 to 0.069 for C-60 and its derivatives 1-4.