The Effect of Oxygen on the Photoconductivity of C60 Film: Action Spectrum and Temperature-Dependence

Abstract

Abstract We report the effect of oxygen on the action spectrum of the steady-state photoconductivity (PC) of C60 film and its temperature dependence. The steady-state PC decreases more than 4 orders of magnitude upon exposure to oxygen; the PC decreases faster below ω≊2.3 eV. The low-temperature PC spectrum of the oxygen-free C60 is similar to the high-temperature PC spectrum of C60 exposed to oxygen. The steady-state PC exhibits a peak at T≊240 K in the oxygen-free C60, which disappears in C60 exposed to oxygen. The results indicate that the oxygen in C60 film acts as an efficient deep trap for photoexcited carriers and reduces the structural order.