凯发

Graphene and related materials (GRMs) hold great potential for flexible (opto) electronics for their novel electrical, optical and mechanical properties. Demonstration of GRM-based prototypes promises the availability of robust, lightweight, and flexible electronics in the near future. The road to realistic applications and commercialization of GRMs requires the assessment of three key factors: cost/performance, mass-production and manufacturability.These factors are not viable for currently available materials, dispersions and inks for flexible (opto) electronics. For example, transparent conducting oxides used in displays are brittle, printable metal nanoparticles for interconnects are not cost-effective and have demanding processing requirements while organic polymers are expensive and have limited environmental stability. GRMs need to be attractive in terms of cost and performance with respect to commercially available conducting and semiconducting materials. Most importantly, for successful commercialization, they need to be produced, processed, characterized and deposited in large-scale with batch-to-batch reproducibility. However, such economic and large-scale production and processing strategy of GRM is still missing.Current growth techniques of GRMs are not cost-effective and unsuited for mass production of low-cost flexible (opto) electronics. Low temperature production and deposition of GRM inks are hence an attractive alternative for large-area printable, flexible (opto) electronics.

GRM inks offer a wide range of device fabrication and integration options, such as digital and lithographic printing, roll-to-roll coating, as well as embedded in polymer composites or other nanomaterials. Liquid Phase Exfoliation (LPE) of the bulk layered materials is a scalable technique ideally suited to produce GRM inks. However, LPE suffers from low yield of GRMs. My research aims to develop high yield,cost-effective andlarge-scale production techniques of GRM inks,and generate a portfolio of reproducible manufacturability processes for future GRM-based printable and flexible (opto)electronic devices and composites.Using graphene as the model system, I will demonstrate cost-effective,up-scalable production processes of high concentration graphene inks,[1] from the bulk layered materials to the ink manufacturing. By combining LPE with ultra-centrifugation processes, I will show formulation of pilot-scale production of stable graphene inks through engineered exfoliation and chemical treatment protocols. Fine tuning of the size and shape of the graphene flakes and their deposition on the substrate controls the final (opto) electronic properties of the printed structure, while the rheology and composition of the graphene inks as well as their interaction with flexible substrates enables the formulation of graphene inks, tailored for various printing and coating methods, such as inkjet, flexographic and screen printing, spray and rod coating. I will discuss realistic pathways to commercialization of graphene inks and demonstrate prototypes including inkjet-printed graphene thin-film transistor,[2] flexible transparent touch pads and inkjet-printed GRM photodetector.[3] Finally, I will present my vision on manufacturability of flexible and wearable electronic and optoelectronic devicesembedding the optical and electrical functionalities of graphene, 2d crystals and their hetero-structures.

References:

[1] F. Bonaccorso, et al.“Large Scale Exfoliation and Sorting of Graphene in Centrifugal Fields”submit. J. Phys. Chem. C (2014).

[2] F. Torrisi, et al.“Ink-Jet Printed Graphene Electronics” ACS Nano, 6, 2992 (2012).

[3] F. Torrisi, et al.“Printed graphene-MoS2 photodetectors” in preparation.