Layer‐by‐Layer Controlled Perovskite Nanocomposite Thin Films for Piezoelectric Nanogenerators

Perovskite nanoparticle‐based nanocomposite thin films strictly tailored using unconventional layer‐by‐layer (LbL) assembly in organic media for piezoelectric nanogenerators (NGs) are demonstrated. By employing sub‐20‐nm BaTiO 3 nanoparticles stabilized by oleic acid ligands (i.e., OA‐BTO NPs ) and carboxylic acid (COOH)‐functionalized polymers, such as poly(acrylic acid) (PAA), the resulting OA‐BTO NP /PAA nanocomposite multilayers are prepared by exploiting the high affinity between the COOH groups of PAA and the BTO NPs . The ferroelectric and piezoelectric performance of the (PAA/OA‐BTO NP ) n thin films can be precisely controlled by altering the bilayer number, inserted polymer type, and OA‐BTO NP size. It is found that the LbL assembly in nonpolar solvent media can effectively increase the quantity of adsorbed OA‐BTO NPs , resulting in the dramatic enhancement of electric power output from the piezoelectric NGs. Furthermore, very low leakage currents are detected from the (PAA/OA‐BTO NP ) n thin films for obtaining highly reliable power‐generating performance of piezoelectric NGs.