Barrier Performance of CVD Graphene Films Using a Facile P3HT Thin Film Optical Transmission Test

Figure 2

(a) Sample architectures for P3HT films spun-cast on glass without any proprietary seal. (i) Bare P3HT, (ii) with PMMA spun-cast from anisole, (iii) P3HT with PMMA (spun-cast) and monolayer graphene (supportive PMMA removed), and (iv) P3HT with monolayer graphene and PMMA (transferred with graphene). (b) P3HT degradation as a function of time for structures i–iv. The removal of PMMA from monolayer graphene during its transfer generates cracks in the film, which results in depleted barrier performance of monolayer graphene, when comparing PMMA/graphene (structure iii) with graphene/PMMA (structure iv). Twofold reduction in P3HT degradation rate is attributed to minimized cracks in graphene film, which can be typically induced by removing the supportive PMMA layer. (c) Raman spectroscopy of graphene with = 2.3 and full width at half maximum (FWHM) of the 2D band around 30 cm⁻¹, indicative of monolayer CVD graphene. (d) shows UV-Vis spectroscopy performed on graphene samples with around 97% transparency measured at 550 nm wavelength, which is another indicative of a monolayer graphene.

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