Wafer scale FeCl3 intercalated graphene electrodes for photovoltaic applications

Abstract

The alteration of graphene's electrical properties through chemical functionalization is a necessary process in order for graphene to fulfill its potential as a transparent conducting electrode. In this work, we present a method for the transfer and intercalation of large area (wafer scale) graphene samples to produce highly doped FeCl 3 intercalated Few Layer Graphene (FeCl 3 -FLG). Given its excellent flexibility, transmission, and a sheet resistance, comparable to that of Indium Tin Oxide, FeCl 3 -FLG has potential to replace alternative flexible transparent electrodes as well as compete with rigid transparent electrodes. We assess the effect of functionalization temperature on the degree of intercalation in the large area samples and comparing results to that of 1 cm 2 FeCl 3 -FLG samples. Raman spectroscopy is then used to characterize samples, where we introduce a new figure of merit ( PosG ) by which to assess the degree of intercalation in a sample. This is an average G peak position, weighted by the areas of the constituent peaks, which can then be used to map the charge carrier concentration of the sample. The inhomogeneity of the graphene grown by chemical vapor deposition is found to be one of the limiting factors in producing large area, high quality FeCl 3 -FLG.

Graphene‐Based Transparent Conductive Films: Material Systems, Preparation and Applications

“…Treating graphene by materials with larger electron positivity leads n‐type doping. There are lots of dopants for graphene including HNO 3 , SOCl 2 , Fe(NO 3 ) 3 , AuCl 3 , FeCl 3 , Na + , pyrene buanoic acid succidymidyl ester, bis(trifluoromethanesulfonyl)amide, bromine, and APTES…”

Graphene-Based Light Sensing: Fabrication, Characterisation, Physical Properties and Performance

“…Contrary to bulk graphite, the intercalation of FLG takes place at relatively low temperatures using a three-zones furnace, it does not require a carrier gas and the time-scale is reduced from tens of days to only 8 hrs. This, together with its environmental stability [ 65 ] and its peculiar plasmonic properties [ 66 ], make FeCl -FLG the ideal candidate for novel opto-electronics devices [ 67 ].…”

Improved Stability of Organic Photovotlaic Devices With FeCl3 Intercalated Graphene Electrodes

“…Transfer and intercalation of FLG samples was performed following the procedures set out in previous works (Khrapach et al, 2012;Walsh et al, 2018). FLG samples grown on Ni/Si/SiO 2 substrates were purchased from Graphene Supermarket, and coated with a protective layer of Poly(Methyl Methacrylate) (PMMA).…”

“…This results in a reduction of the sheet resistance of the intercalated Few Layer graphene (i-FLG) by up to two orders of magnitude (Khrapach et al, 2012), as well as a significant increase in the sample's Work Function (WF) (Bointon et al, 2015). In addition to these highly desirable traits, the i-FLG is stable to high levels of humidity across a wide range of temperatures (Wehenkel et al, 2015) and can be processed in large areas (Bointon et al, 2015;Walsh et al, 2018). i-FLG has so far been demonstrated as a transparent electrode in optoelectronic devices such as photodetectors (Withers et al, 2013;de Sanctis et al, 2017) and flexible lighting devices (Torres Alonso et al, 2016).…”

“…In this investigation we fabricate i-FLG electrodes and use them to produce functioning OPV devices, using PTB7/PC70BM Bulk Heterojunction (BHJ) active layer. The electrical conductivity, optical transmittance and surface morphology of i-FLG has already been characterized and published elsewhere (Khrapach et al, 2012;Bointon et al, 2014Bointon et al, , 2015Wehenkel et al, 2015;Walsh et al, 2018) by our group. These devices are compared to devices fabricated in tandem using commercially available ITO as the anode.…”