Reduced graphene oxide electrodes for large area organic electronics.

Devices based on solution processable organic materials are promising for inexpensive large area electronics on transparent fl exible plastic substrates. [ 1 ] In practice, however, electrodes in organic devices typically consist of vacuum deposited materials that are largely incompatible with this goal. The most widely used transparent electrode for plastic electronics to date is tin-doped indium oxide (ITO). The latter provides a relatively high electrical conductivity ( ≈ 10 4 S cm − 1 ) [ 6 ] with good optical transparency ( > 80%) for visible light. [ 7 ] Furthermore ITO has been used widely on plastic substrates, being compatible with high-throughput deposition processes such as sputtering. However, there are problems associated with ITO: i) it is brittle, which leads to micro-cracking when it is fl exed and a consequent drop in conductivity, ii) there are concerns over the increasing cost of indium (rising from ≈ 350 to ≈ 1000 US$ per kg in recent years) [ 8 ] and its limited abundance, and iii) it is primarily suited to use as an anode material only because of its high work function. Hence there is a clear need for alternative materials, which rival or exceed the performance of ITO and other more traditional electrode metals. [ 9 , 10 ]