High-integration and high-performance micro thermoelectric generator by femtosecond laser direct writing for self-powered IoT devices

Astonishing advances in IoT devices are making a revolutionary progress on smart society, but requiring for sustainable micro power sources. Micro thermoelectric generators (μTEGs) have the potential to power the IoT devices when incorporated into compact microcircuits. Nevertheless, the relatively low output of μTEGs can hardly reach the rated power and voltage for practical use at present. Herein, a femtosecond laser direct writing method is proposed for the fabrication of μTEGs with easy operation and good compatibility, and the precise adjustment of laser energy ensures a high-precision high aspect ratio pattern etch of thermoelectric films. The highly-integrated μTEG (364 pairs/cm²) meets an excellent output of 494 mV and 0.514 mW cm⁻² at ΔT = 33.1 K and an efficiency factor of 0.47 μW cm⁻² K⁻². Eventually, it can realize an output of 3.3 V by using a power manager with the function of stabilizing and drive various electronic components, exhibiting a promising power source for self-powered IoT devices.