All-Printed Dielectric Capacitors from High-Permittivity, Liquid-Exfoliated BiOCl Nanosheets
Yashaswi Nalawade, Joshua Pepper, Andrew Harvey, Aideen Griffin, David Caffrey, Adam G. Kelly, Jonathan N. Coleman
Abstract
Printed networks of insulating two-dimensional (2D) materials are promising for dielectric applications in printed electronic devices. However, this work has not really progressed beyond networks of boron nitride (BN) nanosheets displaying dielectric constants of <6. Here we use liquid-phase exfoliation to demonstrate the production of nanosheets from the high-permittivity, layered material bismuth oxychloride (BiOCl). We first demonstrate liquid exfoliation of BiOCl nanosheets followed by the characterization of the resultant suspensions. We then use aerosol jet printing to print capacitors from patterned heterostacks, consisting of BiOCl nanosheet networks sandwiched between networks of liquid-exfoliated graphene nanosheets. We characterize these capacitors as a function of network thickness, finding a high-network dielectric constant of >40 but a relatively low dielectric strength of 0.67 MV/cm. We also observe an unexpected series capacitance, which we attribute to an internal capacitance associated with inter-nanosheet junctions within the graphene electrodes.