TL;DR: Graphene is a promising next-generation material that was discovered in 2004 as discussed by the authors, which is composed of a two-dimensional lattice made only from carbon and has a high intrinsic resistivity (2KΩ/ ) which is three orders of magnitude greater than the current industry standard ITO.
Abstract: The landscape of consumer electronics has drastically changed over the last decade. Technological advances have led to the development of portable media devices, such as the iPod, smart phones and laptops. This has been achieved primarily through miniaturisation and using materials such as Lithium and Indium Tin Oxide (ITO) to increase energy density in batteries and as transparent electrodes for light emitting displays respectively. However, ten years on there are now new consumer demands, which are dictating the direction of research and new products are under constant development. Graphene is a promising next-generation material that was discovered in 2004. It is composed of a two-dimensional lattice made only from carbon. The atoms are arranged in a two atom basis hexagonal crystal structure which forms a fundamental building block of all sp hybrid forms of carbon. The production of large area graphene has a high cost, due to the long growth times and the high temperatures required. This is relevant as graphene is not viable compared to other transparent conductors which are produced on industrial scales for a fraction of the cost of graphene growth. Furthermore, graphene has a high intrinsic resistivity (2KΩ/ ) which is three orders of magnitude greater than the current industry standard ITO. This limits the size of the electrodes as there is dissipation of energy across the electrode leading to inefficiency. Furthermore a potential drop occurs across the electrode leading to
TL;DR: The sign of the photovoltage changes upon sweeping the chemical potential of the pristine graphene through the charge neutrality point, and it is shown that this is due to the photothermoelectric effect.
Abstract: We investigate the optoelectronic properties of novel graphene/FeCl3-intercalated few-layer graphene (FeCl3-FLG, dubbed graphexeter) heterostructures using photovoltage spectroscopy. We observe a prominent photovoltage signal generated at the graphene/FeCl3-FLG and graphene/Au interfaces, whereas the photovoltage at the FeCl3-FLG/Au interface is negligible. The sign of the photovoltage changes upon sweeping the chemical potential of the pristine graphene through the charge neutrality point, and we show that this is due to the photothermoelectric effect. Our results are a first step toward all-graphene-based photodetectors and photovoltaics.