Correlating the Interfacial Polar-Phase Structure to the Local Chemistry in Ferroelectric Polymer Nanocomposites by Combined Scanning Probe Microscopy

Ferroelectric polymer nanocomposites possess exceptional electric properties with respect to the two otherwise uniform phases,which is commonly attributed to the critical role of the matrix-particle interfacial region.However,the structure-property correlation of the interface remains unestablished,and thus,the design of ferroelectric polymer nanocompos-ite has largely relied on the trial-and-error method.Here,a strategy that combines multi-mode scanning probe microscopy-based electrical charac-terization and nano-infrared spectroscopy is developed to unveil the local structure-property correlation of the interface in ferroelectric polymer nano-composites.The results show that the type of surface modifiers decorated on the nanoparticles can significantly influence the local polar-phase content and the piezoelectric effect of the polymer matrix surrounding the nano-particles.The strongly coupled polar-phase content and piezoelectric effect measured directly in the interfacial region as well as the computed bonding energy suggest that the property enhancement originates from the formation of hydrogen bond between the surface modifiers and the ferroelectric polymer.It is also directly detected that the local domain size of the ferroelectric polymer can impact the energy level and distribution of charge traps in the interfacial region and eventually influence the local dielectric strength.

Graphene-coated conductive probes with enhanced sensitivity for nanoIR spectroscopy

Nano-infrared(nanoIR)probes play a crucial role as nano-mechanical sensors and antennas for light absorption and emission,and their testing performance is critically dependent on their optical properties and structural stability.Graphene-coated dielectric probes are highly attractive for enhancing light–matter interactions and integrating IR photonics,providing a broadband optical response and strong electromagnetic field.However,achieving continuous single-layer graphene growth on non-planar and non-single crystalline dielectrics is a significant challenge due to the low surface energy of the dielectric and the large difference in size between the probe tip,cantilever,and substrate.Herein,we present a novel method for the growth of high-quality and continuous graphene with good conductivity on non-planar and amorphous dielectric probe surfaces using manganese oxide powder-assisted short time heating chemical vapor deposition.The resulting graphene-coated dielectric probes exhibit an average IR reflectance of only 5%in the mid-IR band,significantly outperforming probes without continuous graphene coating.Such probes can not only effectively transduce the local photothermal sample expansion caused by the absorption of IR laser pulses,but also effectively scatter near-field light,which is 25 times stronger than the commercial metal-coated probes,and have advantages in the application of nanoIR sensing based on atomic force microscope-based infrared(AFM-IR)spectroscopy and infrared scattering scanning near field optical microscopy(IR s-SNOM)principles.Furthermore,our graphene growth method provides a solution for growing high-quality graphene on the surfaces of non-planar dielectric materials required for integrated circuits and other fields.