Polymer photovoltaic cells with rhenium oxide as anode interlayer

Abstract

The effect of a new transition metal oxide, rhenium oxide (ReO 3), on the performance of polymer solar cells based on regioregular poly(3-hexylthiophene) (P3HT) and methanofullerene [6,6]-phenyl C 61 -butyric acid methyl ester (PCBM) blend as buffer layer was investigated. The effect of the thickness of ReO 3 layer on electrical characteristics of the polymer solar cells was studied. It is found that insertion of ReO 3 interfacial layer results in the decreased performance for P3HT: PCBM based solar cells. In order to further explore the mechanism of the decreasing of the open-circuit voltage (V oc), the X-ray photoelectron spectroscopy (XPS) is used to investigate the ReO 3 oxidation states. Kelvin Probe method showed that the work function of the ReO 3 is estimated to be 5.13eV after thermal evaporation. The results indicated the fact that a portion of ReO 3 decomposed during thermal evaporation process, resulting in the formation of a buffer layer with a lower work function. As a consequence, a higher energy barrier was generated between the ITO and the active layer.