Electron-doped SrTiO3 is a well-known n-type thermoelectric material, although the figure of merit of SrTiO3 is still inferior compared with p-type metal oxide-based thermoelectric materials due to its high lattice thermal conductivity. In this study, we have used a different amount of the non-ionic surfactant F127 during sample preparation to introduce nanoscale porosities into bulk samples of La-doped SrTiO3. It has been observed that the porosities introduced into the bulk sample significantly improve the Seebeck coefficient and reduce the thermal conductivity by the charge carrier and phonon scattering respectively. Therefore, there is an overall enhancement in the power factor (PF) followed by a dimensionless figure of merit (zT) over a wide scale of temperature. The sample 20 at% La-doped SrTiO3 with 600 mg of F127 surfactant (SLTO 600F127) shows the maximum PF of 1.14 mW m−1 K−2 at 647 K which is 35% higher than the sample without porosity (SLTO 0F127), and the same sample (SLTO 600F127) shows the maximum value of zT is 0.32 at 968 K with an average enhancement of 62% in zT in comparison with the sample without porosity (SLTO 0F127).
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Data accessibility. Data are available from Dryad Digital Repository: https://doi.org/10.5061/dryad.4s6mn56 . Authors’ contributions. A.J.A., S.M.K.N.I., R.H. and M.B. carried out laboratory work, participated in data analysis and participated in the design of the study and drafted the manuscript. J.K., M.K. and M.S.A.H. critically revised the manuscript. Y.Y. and X.W. conceived of the study, designed the study, coordinated the study and helped draft the manuscript. All authors gave final approval for publication and agree to be held accountable for the work performed therein. Competing interests. We declare we have no competing interests. Funding. This work was partially supported by the Australian Research Council (ARC) through a Discovery Project DP 130102956 (X.W.), an ARC Professorial Future Fellowship project (FT 130100778, X.W.) and a Linkage Infrastructure Equipment and Facilities (LIEF) grant (LE 120100069, X.W.). This research was also supported by the Global Connections Fund (Bridging grant scheme) of the Australian Academy of Technology and Engineering (ATSE) in 2019 (M.S.A.H. and Y.Y.). Acknowledgements. Higher degree research of Al Jumlat Ahmed and Sheik Md Kazi Nazrul Islam is supported by the Endeavour Leadership Program of Australian Government. We are thankful to Yaser Rehman, Hamzeh Qutaish and Alexander Morlando for assistance with sample characterization for SEM analysis and BET analysis. This work was also performed in part at the Queensland node of the Australian National Fabrication Facility, a company established under the National Collaborative Research Infrastructure Strategy to provide nano and microfabrication facilities for Australian Researchers.
© 2019 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited.
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