Radio frequency functional capacitors made of all-organic composites of thiourea in field-responsive polymers

Abstract

By incorporating an organic high dielectric constant (κ) ferroelectric crystal, thiourea, in field-responsive polymers, we fabricated radio frequency functional all-organic and solution-processable dielectric composites. Two field-responsive polymer matrices with polyvinylidene fluoride (PVDF) and π-conjugated tris(8-hydroxyquinoline)aluminum(III) inclusions were used to fabricate six model high-κ capacitor devices. Promising frequency-independent capacitance density of about 12nF∕cm2 up to 100MHz with an estimated κ=54 was obtained from the model systems except when thin interpenetrating PVDF crystals formed within the amorphous matrix. These structures displayed significantly lower capacitance density (∼0.7nF∕cm2). High-κ composites with low loss tangent (∼0.03) could be implemented in flexible electronics.