Accelerated automated screening of viscous graphene suspensions with various surfactants for optimal electrical conductivity

Functional composite thin films have a wide variety of applications in flexible and/or electronic devices, telecommunications and multifunctional emerging coatings. The rapid screening of their properties is a challenging task, especially with multiple components defining the targeted properties. In this work we present a platform for accelerated automated screening of viscous graphene suspensions for optimal electrical conductivity. Using an Opentrons OT2 robotic auto-pipettor, we tested 3 most industrially significant surfactants - PVP, SDS and T80 - by fabricating 288 samples of graphene suspensions in aqueous hydroxypropylmethylcellulose. Enabled by our custom motorized 4-point probe measurement setup and computer vision algorithms, we then measured the electrical conductivity of every sample and identified that the highest performance is achieved for PVP-based samples, peaking at 10.8 mS cm-1 without annealing. The automation of the experimental procedure allowed us to perform the majority of the experiments using robots, while the involvement of human researchers was kept to minimum. Overall the experiment was completed in less than 18 hours, only 3 of which involved humans. We robotically produce 288, full-factorial sampled, unique graphene-based drop-casted films, perform automated computer-vision detection followed by thickness and electrical conductivity measurements minimizing human time to similar to 17% of the workflow.