Photocurrent analysis of organic photovoltaic cells based on CuPc/C₆₀ with Alq₃ as a buffer layer

The performance of an organic photovoltaic (OPV) cell based on copper phthalocyanine CuPc/C₆₀ with a tris-(8-hydroxyquinolinato) aluminum (Alq₃) buffer layer has been investigated. It was found that the power conversion efficiency of the device was 1.51% under illumination with an intensity of 100 mW/cm², which was limited by a square-root dependence of the photocurrent on voltage. The photocurrent--optical power density characteristics showed that the OPV cell had a significant space-charge limited photocurrent with a varied saturation voltage and a three quarters power dependence on optical power density. Also, the absorption spectrum was measured by a spectrophotometer, and the results showed that the additional Alq₃ layer has a minor effect on photocurrent generation.