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Flexible piezoelectric sensors have received widespread attention in wearable electronics for their ability to convert mechanical energy into electrical energy, while the insufficient output power and complex preparation process have limited their application. In this work, several honeycomb structures based on graphene macro-film (GAMF) were created via laser engraving, which can utilize negative Poisson's ratio (NPR) properties to improve the output electric performance of flexible piezoelectric sensors. The effect of different electrode materials on the piezoelectric output was investigated in the experiments and compared with the theoretical equations, indicating that the output power of the sensor could be enhanced up to 142 % by improving the materials auxetic mechanical properties. The stability tests have proven that the sensors can operate effectively for a long time under different operating conditions. Moreover, the optimized sensor shows powerful potential for monitoring human movements such as finger tapping, joint bending, and foot stepping. This work opens up a new development path for the preparation of convenient and high-performance wearable electronic devices. The negative Poisson's ratio characteristic of the honeycomb graphene macro-film is used to increase the deformation of PVDF film to increase the electrical output performance of the flexible piezoelectric sensor. The optimized sensor can be used to detect human movements. [Display omitted] • Honeycomb graphene macro-films with different mechanical properties were prepared by laser engraving. • Flexible piezoelectric sensors based on honeycomb graphene macro-films are prepared. • The output performance of piezoelectric sensors can be improved by adjusting mechanical properties of electrode materials. • The flexible piezoelectric sensors can be used to detect human movements. [ABSTRACT FROM AUTHOR]

[Display omitted] • Electrothermal scanners have limited bandwidth due to a large thermal time constant. • Scanner's thermal and inertial mass is reduced using the honeycomb support structure. • As a result, an increase in both bandwidth and efficiency of a scanner is demonstrated. • A sample two-photon 3D images of pollen grain are taken on benchtop system. Design and testing of a low-mass electrothermal vertical scanning mirror for fast axial scanning during multi-photon microscopy is presented. The mirror makes use of a novel honeycomb mechanical support structure to substantially reduce both thermal and inertial mass relative to mirror size. At the same time, undesirable mirror curvature due to residual thermal stress is controlled without adversely affecting the image quality. In addition, the support structure makes the complete mirror area usable which otherwise is not possible in devices that rely on isotropic silicon etching. A high actuator efficiency with static displacement per unit power of 2.08 μm/mW was achieved due to the reduced thermal capacitance at the actuator legs, when using a 700 nm thin structural layer of SiO 2. The resulting scanning mirror achieves open loop time constant as small as 3.42 ms with both thermal and mechanical bandwidths exceeding 100 Hz. Mirror surface non-idealities related to the mirror structure and their influence on image quality are discussed. Sample 3D multi-photon images captured by performing remote scanning in both lateral and axial direction on a benchtop testbed are presented. The efficacy of remote axial scan is ascertained by comparisons with images obtained by moving specimens relative to the objective. [ABSTRACT FROM AUTHOR]