Langmuir-Blodgett deposition and physicochemical surface characterization of two-dimensional perovskite nanosheets on ITO-PET substrates

We successfully obtained Ca2NaNb4O13  single perovskite nanosheets by delaminating x = 4 Dion-Jacobson type KCa2NaNb4O13 layered materials. These nanosheets were then deposited onto conductive, transparent, and flexible indium tin oxide-polyethylene terephthalate (ITO-PET) substrates using the Langmuir-Blodgett (LB) technique. The polar and apolar (dispersive) surface tension components of LB nanofilms composed of Ca2NaNb4O13  perovskite nanosheets and the work of adhesion between the nanofilms and silicon and ITO-PET substrates were determined through contact angle measurements combined with mathematical modeling based on surface thermodynamics. The results showed that the apolar surface tension components had similar values for all surfaces studied, while the polar surface tension components of the nanofilms deposited on the substrates had higher values than those of the bare substrates. The higher polar interaction observed between the nanofilm and ITO-PET resulted in higher total work of adhesion of the nanofilm to the ITO-PET surface in water, while the total work of adhesion computed between the nanofilm and Si was higher in air.