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Films of piezoelectric poly(vinylidene fluoride) (PVDF) and its copolymer P(VDF-TrFE) have been studied intensively for their potential application in piezoelectric sensing devices. The present work focuses on tuning the piezoelectric properties of P(VDF-TrFE) films via incorporating Ag and polydopamine co-decorated PZT (Ag@PDA@PZT) particles. Ag@PDA@PZT particles can effectively improve the β-phase content and piezoelectric properties of P(VDF-TrFE) films. The highest open-circuit voltage and short-circuit current of P(VDF-TrFE)-based flexible pressure sensors incorporating Ag@PDA@PZT particles are ~30 V and ~2.4 μA, respectively. The flexible sensors exhibit a response to different body movements, providing a practical and potentially useful basis for human−machine interface applications. [ABSTRACT FROM AUTHOR]

Simultaneous achievement of large piezoelectric responses and broad service temperature range for power-type applications, such as sensors, actuators and transducers, is challenging due to trade-off between piezoelectric coefficient (d33) and Curie temperature (TC). In this study, manganese dioxide (MnO2) was introduced in 0.04BiYbO3-0.96Pb(Zr0.469Ti0.531)O3 (BY-PZT) matrix, and then based on this, Qm further was improved and tan δ got reduced via optimization of Zr/Ti ratios in the matrix, i.e., by intentional design of Ti nonstoichiometry for inhibiting pyrochlore phase. Results show that doping of appropriate amount of MnO2 led to significant increase in Qm of BY-PZT ceramics from 160 to 274, and tan δ decreased from 2% to 0.3%, while nonstoichiometry with certain Ti-deficiency amount could further increase Qm to 567 and reduce tan δ to 0.2%. Simultaneously, TC was still maintained at relatively high level for high-temperature applications. Ceramics with optimized composition of 0.04BiYbO3-0.96Pb(Zr0.469Ti0.531–1.5%)O3 + 1.3 mol%MnO2 sintered at 1100 °C exhibited optimal electrical properties of d33 = 252 pC·N−1, kp = 0.468, Qm = 567, tan δ = 0.2%, and TC = 389 °C. This study solves the problem of generation of pyrochlore phase during mass production of BY-PZT-based ceramics, and results pave the way for utilizing new power-type piezoelectric ceramic in high-temperature applications. [ABSTRACT FROM AUTHOR]