Effect of Surfactant Concentration Variation on the Thermoelectric Properties of Mesoporous ZnO

Min-Hee Hong,Young Soo Lim,Hyung Hee Cho,Jung-Kun Lee,Hyung-Ho Park,Sangwoo Shin,Chang-Sun Park,Won-Seon Seo

doi:10.1155/2013/172504

Abstract

The electrical and thermal conductivities and the Seebeck coefficient of mesoporous ZnO thin films were investigated to determine the change of their thermoelectric properties by controlling surfactant concentration in the mesoporous ZnO films, because the thermoelectric properties of mesoporous ZnO films can be influenced by the porosity of the mesoporous structures, which is primarily determined by surfactant concentration in the films. Mesoporous ZnO thin films were successfully synthesized by using sol-gel and evaporation-induced self-assembly processes. Zinc acetate dihydrate and Brij-76 were used as the starting material and pore structure-forming template, respectively. The porosity of mesoporous ZnO thin films increased from 29% to 40% with increasing surfactant molar ratio. Porosity can be easily altered by controlling the molar ratio of surfactant/precursor. The electrical and thermal conductivity and Seebeck coefficients showed a close correlation with the porosity of the films, indicating that the thermoelectric properties of thin films can be changed by altering their porosity. Mesoporous ZnO thin films with the highest porosity had the best thermoelectric properties (the lowest thermal conductivity and the highest Seebeck coefficient) of the films examined.

Highlights

The acceleration in global warming has made development of alternative energy sources of critical importance to modern society
Because of their pore structure, mesoporous materials have unique properties such as low thermal conductivity and high specific surface area. They can potentially be used in gas sensor applications and in thermoelectric devices, among many other applications. These materials should have a high Seebeck coefficient and electrical conductivity and low thermal conductivity when applied in thermoelectric devices
Mesoporous structures have low thermal conductivity property, this is accompanied by a decrease in electrical conductivity

Summary

Introduction

The acceleration in global warming has made development of alternative energy sources of critical importance to modern society. It is very difficult to control these factors individually, because electrical conductivity and the Seebeck coefficient have an inverse relationship, this problem can be overcome by the use of nanostructures, such as nanowires and superlattices [1]. Mesoporous structures are those with a pore diameter ranging from 2 to 50 nm [2]. Because of their pore structure, mesoporous materials have unique properties such as low thermal conductivity and high specific surface area They can potentially be used in gas sensor applications and in thermoelectric devices, among many other applications. By exploiting this effect in mesoporous structures, electrical conductivity and thermal

Methods

Results

Conclusion