Advanced Graphene-Based Transparent Conductive

Abstract

New architectures of transparent conductive electrodes (TCEs) incorporating graphene

monolayers in di erent configurations have been explored with the aim to improve the performance

of silicon-heterojunction (SHJ) cell front transparent contacts. In SHJ technology, front electrodes

play an important additional role as anti-reflectance (AR) coatings. In this work, di erent

transparent-conductive-oxide (TCO) thin films have been combined with graphene monolayers in

di erent configurations, yielding advanced transparent electrodes specifically designed to minimize

surface reflection over a wide range of wavelengths and angles of incidence and to improve electrical

performance. A preliminary analysis reveals a strong dependence of the optoelectronic properties of

the TCEs on (i) the order in which the di erent thin films are deposited or the graphene is transferred

and (ii) the specific TCO material used. The results shows a clear electrical improvement when three

graphene monolayers are placed on top on 80-nm-thick ITO thin film. This optimum TCE presents

sheet resistances as low as 55 W/sq and an average conductance as high as 13.12 mS. In addition,

the spectral reflectance of this TCE also shows an important reduction in its weighted reflectance value

of 2–3%. Hence, the work undergone so far clearly suggests the possibility to noticeably improve

transparent electrodes with this approach and therefore to further enhance silicon-heterojunction cell

performance. These results achieved so far clearly open the possibility to noticeably improve TCEs

and therefore to further enhance SHJ contact-technology performance.