Single‐Step Dip Coating of Crack‐Free BaTiO 3 Films >1 μm Thick: Effect of Poly(vinylpyrrolidone) on Critical Thickness

BaTiO 3 coating films were prepared from Ba(CH 3 COO) 2 –Ti(OC 3 H 7 i ) 4 –H 2 O–CH 3 COOH–C 3 H 7 i OH solutions containing poly(vinylpyrrolidone) (PVP) via single‐step, nonrepetitive dip coating. The critical thickness—i.e., the maximum film thickness achieved without crack formation via nonrepetitive dip coating—was successfully increased by incorporation of PVP in the precursor solution. Relatively dense, crack‐free BaTiO 3 films >1 μm in thickness were achieved via single‐step deposition using a solution containing PVP of average molecular weight of 630 000. Incorporation of an excess amount of PVP, however, led to a decrease in the critical thickness. Higher‐molecular‐weight PVP was more effective in increasing the critical thickness, whereas N‐vinyl‐2‐pyrrolidone monomers did not affect the critical thickness. Stepwise heating of the gel films resulted in increased optical transmittance of the films, accompanied by film densification.