Ultrahigh energy harvesting ability of PVDF incorporated with 2D halide perovskite nanosheets via interface effect

Two-dimensional (2D) perovskites have recently emerged as an new family of ferroelectrics and attracted extensive attention for their specific surface interface characteristics benefitting from the unique structure by inserting hydrophobic organic cations into conventional three-dimensional frameworks. In this study, 2D metal-organic perovskite nanosheets, (C4H9NH3)(2)CsPb2Br7, ((BA)(2)CsPb2Br7), were successfully synthesized by facile temperature-cooling method and introduced into poly (vinylidene fluoride) (PVDF) polymer fibers to construct flexible piezoelectric energy harvester (PEH). (BA)(2)CsPb2Br7/PVDF nanofibers reveal a high piezoelectric coefficient (d(33)) of 63.3 pm/V, which is 2.9 times of the PVDF polymer (21.7 pm/V). Principally, the PVDF composite with 5 wt% (BA)(2)CsPb2Br7 nanosheet filler assumes an superior electroactive phase amount of about similar to 93 % profiting from the interfacial interaction between BA(+) cations of (BA)(2)CsPb2Br7 and the dipoles of PVDF. The PEH based on (BA)(2)CsPb2Br7 nanosheets embedded in PVDF fibers showed a maximum output voltage, 135 V, which is almost 17 times of the PEH based on neat PVDF fibers. Furthermore, the interfacial interaction between (BA)(2)CsPb2Br7 and PVDF was analyzed by first principle DFT study which reveals electrons migrate and the interfacial polarization between the interface. Simultaneously, (BA)(2)CsPb2Br7/PVDF composite fibers based PEH reveals exceptional long-term stabilities and durability. More attractively, the exceptional performance of this fabricated PEH evinces a pressure sensitivity of similar to 7.3 V/N and bio-mechanical harvesting behavior arising from varied human motions, such as beating, pressing, twisting, walking and running. This cost-effective and high performance of (BA)(2)CsPb2Br7/PVDF based PEH is favorable for the continuation of 2D halide perovskites for further application in new energy and biomechanical filed.