What is "nanogenerator"

n. Any electrical generator whose scale is measured in nanometers; they typically create electricity from the random movements of their surroundings

Nanogenerator is a type of technology that converts mechanical/ thermal energy as produced by small-scale physical change into electricity. Nanogenerator has three typical approaches: piezoelectric, triboelectric, and pyroelectric nanogenerators. Both the piezoelectric and triboelectric nanogenerators can convert the mechanical energy into electricity. However, the pyroelectric nanogenerators can be used to harvest thermal energy from a time-dependent temperature fluctuation.