This paper proposes a bimorph piezoelectric vibration energy harvester (PVEH) with a flexible 3D meshed-core elastic layer for improving the output power while lowering the resonance frequency. Owing to the high void ratio of the 3D meshed-core structure, the bending stiffness of the cantilever can be lowered. Thus, the deflection of the harvester and the strain in the piezoelectric layer increase. According to vibration tests, the resonance frequency is 15.8% lower and the output power is 68% higher than in the conventional solid-core PVEH. Compared to the solid-core PVEH, the proposed meshed-core PVEH (10 mm × 20 mm × 280 μm) has 1.3 times larger tip deflection and the maximum output power is 24.6 μW under resonance condition at 18.7 Hz and 0.2G acceleration. Hence it can be used as a power supply for low-power-consumption sensor nodes in wireless sensor networks.

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In this study, we propose a solidified ionic liquid with a 3D microstructure to increase its surface area for the performance enhancement of a vibration energy harvester (VEH). By soft lithography in MEMS technologies, the use of a mold is proposed to perform the solidification, polarization, and microstructure transfer of the solidified ionic liquid simultaneously. We fabricated six samples with different surface shapes and sizes to compare the power generation performance characteristics of VEHs using a solidified ionic liquid. According to a vibration test, the performance of the VEH with nanometer roughness was improved at a 10 Hz frequency. Also, the output power of the VEH with a micro-folded hollow conical structure was improved at a 50 Hz frequency.

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We investigated the shape of a well to trap single cells for the purpose of improving the cell trapping rate after cell seeding and liquid exchange in a cell microarray. The wells having vertical and inclined tapered side‐wall were made using three‐dimensional UV photolithography. Changes in cell trapping rate by the shape of the wells were evaluated by trapping tests with fluorescent microbeads and living cells. As a result of trapping test with living cells, bead residual rate of the microarray with inclined tapered wells is up to 2.9 times higher than that with vertical wells.