Investigation on the small molecular organic solar cells with PEDOT:PSS/ZnPc double anode buffer layer system

In this paper, the performances of small molecular organic solar cells based on CuPc/C 60 were studied, including the CuPc/C 60 cells without any anode buffer layers and the cells with Zinc-phthalocyanine (ZnPc), PEDOT:PSS, PEDOT:PSS/ZnPc system as an anode buffer layer, respectively. The mechanisms of these three kinds of anode buffer layers were discussed. The results showed that ZnPc layer increases the open-circuit voltage, from 0.372 V to 0.479 V. PEDOT:PSS layer increases the short-circuit current density, from 1.943 mA/cm 2 to 3.752 mA/cm 2. The PEDOT:PSS/ZnPc system enhances both of them. The open-circuit voltage increases from 0.372 V to 0.482 V, and the short-circuit current density increases from 1.943 mA/cm 2 to 3.810 mA/cm 2 and the power conversion effciency increases more than 2 times. It is found that the main reasons are ZnPc can make holes transport easily and PEDOT:PSS can smooth the surface of ITO.