Printable ferroelectric PVDF/PMMA blend films with ultralow roughness for low voltage non-volatile polymer memory

Here, a facile route to fabricate thin ferroelectric polyvinylidene fluoride) (PVDF)/poly(methylmethacrylate) (PMMA) blend films with very low surface roughness based on spin-coating and subsequent melt-quenching is described. Amorphous PMMA in a blend film effectively retards the rapid crystallization of PVDF upon quenching, giving rise to a thin and flat ferroelectric film with nanometer scale β-type PVDF crystals. The still, flat interfaces of the blend film with metal electrode and/or an organic semiconducting channel layer enable fabrication of a highly reliable ferroelectric capacitor and transistor memory unit operating at voltages as low as 15 V. For instance, with a TIPS-pentacene single crystal as an active semi-conducting layer, a flexible ferroelectric field effect transistor shows a clockwise I-V hysteresis with a drain current bistability of 10³ and data retention time of more than 15h at ±15 V gate voltage. Furthermore, the robust interfacial homogeneity of the ferroelectric film is highly beneficial for transfer printing in which arrays of metal/ferroelectric/metal micro-capacitors are developed over a large area with well defined edge sharpness.