Progress in developing next generation of OLED and photovoltaic devices is limited by the lack of suitable transparent electrode materials. CVD graphene lends itself as an ideal candidate with high optical transmission and flexibility. However it is limited as a transparent electrode due to the high intrinsic resistivity and poor work function matching required for efficient operation of solar cells and OLED devices.
We present the functionalization of multilayer CVD graphene by FeCl3intercalation to create a transferable and scalable alternative to current transparent conductors. The intercalation process has been previously shown to reduce the resistivity by 3 orders of magnitude while leaving the optical transmission nominally unchanged for exfoliated graphene . We build on this technique and demonstrate up scaling to produce FeCl3 intercalated CVD graphene with improved electrical properties, high uniformity and no significant change in the optical properties. Furthermore we observe a significant increase in the work function of intercalated graphene, therefore reducing the dependence on lossy work function matching hole injection layers required for efficient OLED and photovoltaic devices.
 Khraphach et al. Adv. Matt. 2012 DOI: 10.1002/adma.201200489