Study of the absorption coefficient of graphene-polymer composites

K Zeranska-Chudek,A M Witowski,A Duzynska,A Lapinska,M Zdrojek,M Pawlowski,J Judek,A Wroblewska

doi:10.1038/s41598-018-27317-0

K Zeranska-Chudek, A M Witowski + Show 6 more

Open Access

https://doi.org/10.1038/s41598-018-27317-0

Copy DOI

Abstract

In this work, we have prepared a series of polydimethylsiloxane (PDMS) composites containing various graphene flakes loadings (0.02–2 wt%), and their broadband optical properties are being investigated. We demonstrate the tunability and evolution of transmittance and reflection spectra of the composites in a wide spectral range (0.4–200 μm) as a function of graphene content. Using these data we derive the broadband wavelength-dependent absorption coefficient (α) values. Our results show that α is roughly constant in the visible and IR ranges, and, surprisingly, is approximately one order of magnitude lower in the terahertz regime, suggesting different terahertz radiation scattering mechanism in our composite. Our material could be useful for applications in optical communication, sensing or ultrafast photonics.

Highlights

Polymer composites combine flexibility and durability of an elastomer matrix with properties of the filler such as nanoparticles or graphene
We demonstrate a systematic study of broadband optical properties of graphene flakes immersed with variable concentration (0.02 to 2 wt%) in PDMS polymer matrix
Graphene flakes used as a nanofiller in a polymer composite have direct influence on the material transmittance

Summary

Results and Discussion

All optical spectra remain relatively flat, except for small peaks around 1.15 μm, which are related to CH3 stretch vibrations characteristic for PDMS material[47]. For samples with higher graphene load the reflectance drops below this value, which might be related to a very high absorption level of those samples. The reflectance values of our composites are significantly lower than those of bulk graphite[53] and approaching the values of mono- to a few layer graphene samples that show reflectance of roughly 1 to 2%2 Both transmittance and reflectance data are used to derive the absorption values of our composite for the VIS-NIR spectra range (see Fig. 2(c)). It is likely that the mechanism based on internal multiple reflection is negligible All this provides two conclusions: first, the main mechanism responsible for blocking the light in the studied range is the absorption and secondly, only small fraction of graphene in the material is needed to fully tune its optical properties.

Corresponding number of graphene layers

Conclusions

Author Contributions

Additional Information