Photocurrent characteristics of ferrocene/flavin/viologen/TCNQ heterojunction

A molecular photodiode was fabricated with the hetero-langmuir-Blodgett (LB ) film consisting of an electron donor (D), sensitizer (S), relay (R) and a cceptor (A). Ferrocene, flavin, viologen and TCNQ were used as D, S, R and A units, respectively. By aligning hetero-LB film of D/S/R/A units on ITO g lass with an aluminum thin film, a molecular photodiode with the structure of Metal/Insulator/Metal (MIM) was constructed. Due to excitation by irradi ation with a 460 nm monochromatic light source, the photoswitching function was observed. And action spectrum of MIM device was measured. To investiga te the photoswitching time and charge transport rate, transient photocurren t of MIM device was measured. Result shows that efficient charge transport from D to A in the heterojunction was occurred due to the existence of R an d less recombination.