Thermoelectric Material Based On TiO2 Doped CuCrO2 by Sol-Gel Method
Noni Surtiana Silalahi (a), Syahrul Humaidi (a*), Agung Imaduddin (b), Nono Darsono (b), Doli Bonardo (a)

(a) Post Graduate Program (Physics), FMIPA, Universitas Sumatera Utara, Jl. Bioteknologi I Kampus USU, Medan, 20155, Indonesia
*syahrul1[at]usu.ac.id
(b) Research Center for Advanced Materials, National Research and Innovation Agency (BRIN), Tangerang Selatan, Banten, 15314, Indonesia

Abstract

A CuCrO2-based thermoelectric material with a delaffosite structure was prepared using the sol-gel technique with the addition of TiO2 dopant as a modifier agent. The sol-gel process which is considered effective for modifying the surface of substrates is applied in the process of preparing CuCrO2 thermoelectric material because this process allows modification of the crystal structure, so that it can be observed its effect on its thermoelectric characteristics. Urea is used as a precipitating agent in the success of the sol-gel process, besides that urea is also a mesopore-directing agent for a modified sol-gel process. The calcination and sintering process after the pelletization of CuCrO2 was carried out at a temperature of 1000 oC for 10 hours each to strengthen the crystallization process of the sample. X-Ray Diffraction (XRD) test showed a decrease in the crystallinity of the CuCrO2 phase structure and an increase in the amount of impurities. However, the crystal structure of the CuCrO2 phase did not experience any changes or crucial defects, so that the delaffosite structure could still be maintained when the addition of TiO2 reached 0.1 wt%. Based on the results of SEM (Scanning Electron Microscope) morphology observations, it was observed that the addition of TiO2 dopants had an impact on increasing the density between grains, and changing the nanostructure of the grains from nanoplates to nanodots. Changes in the nanostructure of CuCrO2 cause an increase in its thermoelectric properties, this can be associated with an increase in the specific surface area that occurs as a result of the addition of TiO2 to the CuCrO2 phase with a delaffosite structure.

Keywords: Thermoelectric material- CuCrO2- TiO2- Sol-gel method

Topic: Materials Sciences: Synthetic and Characterization