Application of poly(3,4-ethylenedioxythiophene):polystyrenesulfonate in polymer heterojunction solar cells

In this study, p-type semiconducting polymer of acid, poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS), has been employed as a hole-transporting electrode to fabricate organic polymer heterojunction photovoltaic cells. The results showed that the resultant poly(3-hexylthiophene): C60 derivatives [6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM)/PEDOT:PSS can significantly expand the light absorption range which was expected to enhance the sunlight excitation. The influences of annealing conditions and barrier layer on the photoelectric performances were investigated in detail, giving an optimized synthesis conditions: annealed temperature was at 120 °C for 90 min, the thickness of PEDOT:PSS film was approximately 3–4 μm, and the ratio of PCBM and P3HT was 1:2. The blended heterojunction consisting of PCBM and P3HT was used as charge carrier-transferring medium to replace I3 −/I− redox electrolyte, showing a short-circuit current of 4.30 mA cm−2, an open-circuit voltage of 0.83 V, and a light-to-electric energy conversion efficiency of 2.37 % under a simulated solar light irradiation of 100 mW cm−2. In addition, a solid-state polymer heterojunction photovoltaic cells with a short-circuit current of 3.59 mA cm−2, an open-circuit voltage of 0.80 V, and a light-to-electric energy conversion efficiency of 1.9 % was successfully fabricated by simplifying the process.