MEMS Radioisotope-Powered Piezoelectric µ - Power Generator (RPG)

We present a microfabricated die-scale Radioisotope-powered Piezoelectric µ -power Generator (RPG) with nuclear to electrical conversion efficiency as high as 3.7%. The generator employs direct charging to convert radiated β-particle kinetic energy into stored electromechanical energy in a piezoelectric unimorph, and piezoelectricity to convert the stored mechanical energy into extractable electrical energy. The generator goes through a charge-discharge-vibrate cycle, integrating the energy collected during the charging phase. This enables high power output (1.13 µ W peak across a 90 kΩ load impedance) for a short time (10 s) during the vibration cycle, even with radioactive film emitting only 100 nW of continuous power.