A thermoelectric converter including a thermoelectric generator and a radiation source. The thermoelectric generator includes a hot source, a cold source, n-type material, and p-type material. The radiation source emits ionizing radiation that increases electrical conductivity. Also detailed is a method of using radiation to reach high efficiency with a thermoelectric converter that includes providing a thermoelectric generator and a radiation source, with the thermoelectric generator including a hot source, a cold source, n-type material, and p-type material, and emitting ionizing radiation with the radiation source to increase the electrical conductivity which strips electrons in the n-type material, the p-type material, or both the n-type material and p-type material from their nuclei with the electrons then free to move within the material.