Efficiency enhancement of polymer photovoltaic devices hybridized with ZnO nanorod arrays by the introduction of a vanadium oxide buffer layer

The introduction of an electron-blocking layer of vanadium oxide between the organic layer and the Ag electrode was studied as a means of improving the performance of bulk heterojunction photovoltaic devices based on poly(3-hexylthiophene): (6,6)-phenyl C₆₁ butyric acid methyl ester hybridized with vertically aligned ZnO nanorod arrays. The power conversion efficiency was further improved to 3.9% by applying a short circuit current density of 10.4 mA cm^-2, an open circuit voltage of 0.58 V, and a fill factor of 65% under AM1.5 100 mW cm^-2 irradiation, owing to the electron collection “antenna” effect of the ZnO nanorod arrays.