Chemically Modified Graphene Oxide as Hole Transport Layers in Oganic Solar Cells
Organic solar cells have emerged as a promising low-cost renewable energy source due to their potential for light weight, high mechanical flexibility and large-area solar energy conversion. Recently, the technology now offer in excess of 10% power conversion efficiency, and Intel,3M, Merck and other Multi-National Corporation study on this technology. Good interface materials not only enhance efficiency but also increase stable of organic solar cell devices. Poly (3, 4-ethylenedioxythiophene): poly (styrenesulfonate) (PEDOT:PSS), has been most commonly used as a solution-process hole transport layer to improve anode contact and to increase hole collection in organic electronic devices. Several problems of the PEDOT:PSS includes high acidity, hygroscopic properties, and inhomogeneous electrical properties, resulting in poor long-term stability.
Graphene oxide is a kind of graphene derivatives, and with it as the electron blocking layer has been used in organic solar cells. The work function of commercial graphene oxide is only 4.9-5.9eV, so we use oxygen plasma treated graphene oxide with a work function of 5.2 eV as a high perfromance hole transport layer for organic solar cells. The high transparency and high work function simultaneously increases short circuit current, threshold voltage and fill factor, resulting in a 30% increase in cell efficiency. This result indicated that the power conversion efficiency of organic solar cells can be improved though controlling the work function of interface materials.
Chemical Modified Graphene Oxide as Hole Transport Layers in Organic Solar Cells
Dong Yang, Lingyu Zhou, Lingcheng Chen, Bin Zhao, Jian Zhang* and Can Li*
Chemical Communications, 2012, DOI:10.1039/C2CC33829G