Functionality and Activity of Sol-Gel-Prepared Co and Fe co-Doped Lead-Free BTO for Thermo-Optical Applications

Mohammed Tihtih; Jamal Eldin F M Ibrahim; Mohamed A Basyooni; Redouane En-Nadir; Irina Hussainova; István Kocserha

doi:10.1021/acsomega.2c07660

Functionality and Activity of Sol-Gel-Prepared Co and Fe co-Doped Lead-Free BTO for Thermo-Optical Applications

ACS Omega. 2023 Jan 25;8(5):5003-5016. doi: 10.1021/acsomega.2c07660. eCollection 2023 Feb 7.

Authors

Mohammed Tihtih¹, Jamal Eldin F M Ibrahim², Mohamed A Basyooni^{3

4}, Redouane En-Nadir⁵, Irina Hussainova⁶, István Kocserha¹

Affiliations

¹ Institute of Ceramics and Polymer Engineering, University of Miskolc, Egyetemvaros, MiskolcH-3515, Hungary.
² Department of Materials Technology, University of Bahri, Khartoum12217, Sudan.
³ Department of Nanotechnology and Advanced Materials, Graduate School of Applied and Natural Science, Selçuk University, Konya42030, Türkiye.
⁴ Science and Technology Research and Application Center (BITAM), Necmettin Erbakan University, Konya42090, Türkiye.
⁵ LPS, FSDM, Sidi Mohammed Ben Abdellah University, Fes30000, Morocco.
⁶ Department of Mechanical and Industrial Engineering, Tallinn University of Technology, Ehitajate Tee 5, 19086Tallinn, Estonia.

Abstract

The BTO, BFTC, and BCTF compounds were synthesized by the sol-gel method. The XRD study revealed the formation of single-phase tetragonal perovskite structures with the space group (P4mm). The crystalline parameters were studied as a function of Fe and Co contents and occupation of Ba and/or Ti sites by Fe and Co in the BTO lattice. It was found that the obtained strain increases when Ba²⁺ is substituted by Co²⁺ and Ti⁴⁺ by Fe³⁺. The Raman investigation confirmed the existence of three active modes (B1/E (TO1LO), (E (TO)/A1(TO3), and (A 1(LO)/E (TO), all of which are related to the existence of the tetragonal phase and strongly support the XRD results. The microstructural study showed a clear correlation between the presence of Fe and Co and the grain size distribution. Optical studies revealed the improvement in band gap energy with transition-metal (Fe and Co) co-doped BTO ceramics. The decrease in the band gap is explained by the competing effects of Columbian interactions, microdeformation, and oxygen defects. The results indicate that the presence of Fe and Co dopants enhances the absorption in the BTO ceramic. The dopants demonstrated an effect on thermal conductivity: they decreased the thermal conductivity of BTO, which is in the range of 0.76-2.23 W m^-1 K^-1 at room temperature and 2.02-0.27 W m^-1 K^-1 at elevated temperatures. The microstructure of the manufactured materials and the grain size distribution affect the compressive strength.