Development of a quality control process for high-quality and reproducible printable graphene conductive electrodes

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Solar panels are on the verge of facing an electrode crisis, given they normally use silver electrodes, which stocks are currently depleting and they are the most expensive element of the device. In that sense, the solar panel industry is urgently seeking for an alternative electrode material, with more sustainable and low-cost character. Graphene electrodes represent ideal candidates as graphene (a carbon allotrope) is a low-cost, widely Earth-abundant element that can exhibit high electrical conductivity. Graphene (Work function ~ -5.0 eV) have the potential to replace the metals (Ag, Cu, Al, Au, work functions = 4.3-5.1 eV) currently used as the black electrode of photovoltaic devices, with the advantage of exhibiting higher electrochemical stability. In addition, the specific hydrophobicity of graphene can also significantly enhance the stability of the solar cells, protecting them from water/moisture ingress. Finally, a very important advantage inherent to graphene resides in the fact its application as electrode is extremely simple, using straightforward and high-throughput methods matching industrial printing deposition techniques.Unfortunately, to date most graphene-based printable inks exhibit significant batch-to-batch variations and low conductivity values due to the absence of a well-defined production and quality control protocol. These variation led to non-reliable performance of the graphene electrodes regarding their electrical (conductivity) and mechanical (adhesion and flexibility) properties.Thus, the ongoing research on highly conductive (with ~1 Ohm/sq sheet resistance, which is required for photovoltaics) graphene-based electrodes was rather limited to date, as the most graphene inks available on the market are not capable to produce highly conductive electrodes. Thus, highly conductive and reproducible graphene-based inks are not available on the market to date, a characteristic which will enable their application in many different sectors in electronics.Our start-up company has the know how and the licence for a revolutionary method to produce, on large scales, highly conductive graphene-based printable inks. With this project we will work to establish a quality control protocol which will enable the inks reaching the full potential regarding reliable operation in terms of reproducibility and mechanical robustness, properties that are really important for applications such as solar panels.