Verification and improvement of power generation under the uniform temperature environment by the poly-crystalline clathrate

Abstract

A novel electric power generation different from the Seebeck effect by using poly-crystaline Ba₈Au_xSi_46-x clathrate consisted of two layers, n-type and p-type materials, was devised. In order to investigate composition dependence of generated voltage, poly-crystalline clathrate samples consisted of two layers with various Au composition were prepared by SPS method. According to composition analysis, the mixed layer was formed at the interface of two layers. The sample consisted of n-type Ba₈Au_4.5Si_41.5 / p-type Ba₈Au_5.5Si_40.5 can generate around 2.0 mV at 723 K under no temperature difference. It is considered that this voltage was caused by charge separation with the diffuse of electrons and holes exited at mixed layer with narrower band gap part on interface. Ba₈Au_4.0Si_42.0 / Ba₈Au_6.0Si_40.0 and Ba₈Au_4.8Si_41.2 / Ba₈Au_5.2Si_40.8 samples showed around 4.0 and 1.0 mV at 723 K, respectively. These results suggested that the voltage increased with difference of Fermi level between n- and p-type semiconductors.