title: Laser-patterned functionalized CVD-graphene as highly transparent conductive electrodes for polymer solar cells.
abstract: A five-layer (5L) graphene on a glass substrate has been demonstrated as a transparent conductive electrode to replace indium tin oxide (ITO) in organic photovoltaic devices. The required low sheet resistance, while maintaining high transparency, and the need of a wettable surface are the main issues. To overcome these, two strategies have been applied: (i) the p-doping of the multilayer graphene, thus reaching 25 Ω□-1or (ii) the O2-plasma oxidation of the last layer of the 5L graphene that results in a contact angle of 58° and a sheet resistance of 134 Ω□-1. A Nd:YVO4laser patterning has been implemented to realize the desired layout of graphene through an easy and scalable way. Inverted Polymer Solar Cells (PSCs) have been fabricated onto the patterned and modified graphene. The use of PEDOT:PSS has facilitated the deposition of the electron transport layer and a non-chlorinated solvent (ortho-xylene) has been used in the processing of the active layer. It has been found that the two distinct functionalization strategies of graphene have beneficial effects on the overall performance of the devices, leading to an efficiency of 4.2%. Notably, this performance has been achieved with an active area of 10 mm2, the largest area reported in the literature for graphene-based inverted PSCs.
authors.affiliation: CHOSE (Centre for Hybrid and Organic Solar Energy), Department of Electronic Engineering, University of Rome Tor Vergata, via del Politecnico 1, 00133 Rome, Italy. reale@ing.uniroma2.it.
authors.forename: Luca
authors.initials: L
authors.lastname: La Notte
authors.forename: Enrica
authors.initials: E
authors.lastname: Villari
authors.forename: Alessandro Lorenzo
authors.initials: AL
authors.lastname: Palma
authors.forename: Alberto
authors.initials: A
authors.lastname: Sacchetti
authors.forename: Maria
authors.initials: M
authors.lastname: Michela Giangregorio
authors.forename: Giovanni
authors.initials: G
authors.lastname: Bruno
authors.forename: Aldo
authors.initials: A
authors.lastname: Di Carlo
authors.forename: Giuseppe Valerio
authors.initials: GV
authors.lastname: Bianco
authors.forename: Andrea
authors.initials: A
authors.lastname: Reale