Environmental energy harvesting based on thermoelectric generation（TEG）device is of great significance for the development of future charge-free electronic devices.A vertical micro flexible thermoelectric device is prepared by using a flexible polyimide substrate

optimizing the size of substrate and thermoelectric particles

and non-destructive segmentation of the substrate.When the temperature of the hot side is 33 ℃ and that of the cold side is 13 ℃

an open circuit voltage of 155.1 mV is generated

an maximum output power can achieve 0.81 mW

a specific power density of 9.34 mW/g or 2.53 mW/cm~2.The minimum bending radius of the device can reach 9 mm.These results show that the design method for flexible thermoelectric module in this paper is successful

that is

together with a flexible substrate

reducing the size of the thermoelectric device and module could solve the problematic brittleness of bismuth telluride material when making flexible thermoelectric device.This design principle give the device a certain flexibility while ensuring its power generation capacity

so that the device can work quite well with heat sources with a curved surface

for example

working as a wearable power source for skin sensors.