Electronic Origins of Large Thermoelectric Power Factor of LaOBiS2-xSex

TL;DR

This study investigates how selenium substitution in LaOBiS2-xSex enhances thermoelectric power factor by increasing electrical conductivity and carrier mobility without reducing the Seebeck coefficient, revealing electronic origins.

Contribution

It provides new insights into the electronic mechanisms behind improved thermoelectric performance in LaOBiS2-xSex through detailed transport property analysis.

Findings

Se substitution increases electrical conductivity.

Carrier mobility increases with Se content.

Seebeck coefficient remains large despite increased conductivity.

Abstract

We examined the electrical transport properties of densified LaOBiS2-xSex, which constitutes a new family of thermoelectric materials. The power factor increased with increasing concentration of Se, i.e., Se substitution led to an enhanced electrical conductivity, without suppression of the Seebeck coefficient. Hall measurements indicated that the low electrical resistivity resulted from increases in the carrier mobility, and the decrease in carrier concentration led to large absolute values of the Seebeck coefficient of the system.