Rapid Microwave-Assisted Hydrothermal Growth of ZTO Nanowires through Systematic Parameter Optimization

Zinc–tin oxide (ZTO) is a ternary metal oxide that offers promising properties for applications in electronics, energy harvesting and sensing devices due to its high electron mobility, chemical stability and tunable optical properties [1]. Among the different synthesis techniques, microwave-assisted hydrothermal synthesis has emerged as an efficient approach for producing nanostructured materials due to its fast and homogeneous heating [2]. However, the morphology and crystalline phases obtained are strongly influenced by the synthesis parameters employed [3]. In this work, the influence of solution volume, microwave power and synthesis time on the formation of ZTO nanowires was systematically investigated. Two solution volumes (7.5 mL and 15 mL), two microwave powers (75 W and 100 W) and synthesis times ranging from 2 to 4 h were evaluated to identify optimal synthesis conditions. The resulting nanostructures were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) to assess morphology, crystalline structure and chemical bonding. Overall, the results demonstrate that synthesis time, microwave power and solution volume play critical roles in controlling ZTO nanowire morphology and growth. By optimizing these parameters, ZnSnO₃ nanowires with comparable morphological and crystallinity quality to those obtained via conventional oven-based hydrothermal synthesis [4] were successfully produced in only 4 h, corresponding to a reduction of 20 h in synthesis time.

Acknowledgements: This work is funded by National Funds through FCT - Portuguese Foundation for Science and Technology, References LA/P/0037/2020, UIDP/50025/2020 and UIDB/ 50025/2020 and the project FOLOW (2023.11887.PEX). This work also received funding from the European Community's H2020 program [GA No. 101008701 (EMERGE)].

References

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[3] Rovisco, A. et al., Nanomaterials 2019, 9, 1002.

[4] Rovisco, A. et al., ACS Appl. Nano Mater. 2018, 1, 3986–3997.