Enhancing the Performance of Flexible BCZT NWs/PDMS Piezoelectric Sensor by Doping Ce³⁺ Ions Into BCZT Nanowires

Lead-free and environmentally friendly ceramic materials have been attracted extensive attention in flexible piezoelectric devices. In this work, a series of Ce³⁺ doped Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃ (BCZT-x Ce³⁺) nanowires (NWs), with different molar ratios of Ce³⁺ to BCZT (x), are synthesized using a two-step hydrothermal reaction method with HZTO NWs as a precursor. Flexible composites are prepared by dispersing BCZT-x Ce³⁺ NWs into polydimethylsiloxane (PDMS) matrix. The BCZT-0.001 Ce³⁺ NWs/PDMS composite is found to have a piezoelectric coefficient (d₃₃) as high as 223.2 pC·N⁻¹, which is 393% higher than that of the pure BCZT NWs/PDMS composite. The BCZT-0.001 Ce³⁺ NWs/PDMS composite shows the optimal sensing properties with output open-circuit voltage and short-circuit current of 9.04 V and 53 nA, respectively, which is significantly higher than that of the BCZT NWs/PDMS composite. Moreover, the sensor features a voltage – pressure linearity in the ultra-wide pressure range of 2.22 to 155.56 kPa, with sensitivity of 0.0565 V·kPa⁻¹, and a good durability over 10 000 cycles. Further demonstration shows that the sensor is suitable for monitoring human motion at low-frequency such as 2 Hz, with an ultra-fast response time of ≈120 ms, making it a promising candidate for applications in the fields of human health monitoring and artificial intelligence.