Flexible high-performance microcapacitors enabled by all-printed two-dimensional nanosheets

All-printed microcapacitors made of high-k perovskite nanosheets (i.e., Ca2Nb3O10 and Ca2NaNb4O13) with different electrodes are prepared by inkjet printing. The dielectric constant of the microcapacirors with graphene electrode is nearly-four times higher than those with silver electrodes. These inkjet-printed microcapacitors exhibited large capacitance density of 150 nF/cm2, high dielectric constant up to 200, excellent flexibility, and thermal stability up to 200 ℃. [Display omitted] Chemically exfoliated nanosheets have exhibited great potential for applications in various electronic devices. Solution-based processing strategies such as inkjet printing provide a low-cost, environmentally friendly, and scalable route for the fabrication of flexible devices based on functional inks of two-dimensional nanosheets. In this study, chemically exfoliated high-k perovskite nanosheets (i.e., Ca2Nb3O10 and Ca2NaNb4O13) are well dispersed in appropriate solvents to prepare printable inks, and then, a series of microcapacitors with Ag and graphene electrodes are printed. The resulting microcapacitors, Ag/Ca2Nb3O10/Ag, graphene/Ca2Nb3O10/graphene, and graphene/Ca2NaNb4O13/graphene, demonstrate high capacitance densities of 20, 80, and 150 nF/cm2 and high dielectric constants of 26, 110, and 200, respectively. Such dielectric enhancement in the microcapacitors with graphene electrodes is possibly attributed to the dielectric/graphene interface. In addition, these microcapacitors also exhibit good insulating performance with a moderate electrical breakdown strength of approximately 1 MV/cm, excellent flexibility, and thermal stability up to 200 ℃. This work demonstrates the potential of high-k perovskite nanosheets for additive manufacturing of flexible high-performance dielectric capacitors.