Daniel Pokorný is a PhD student in Organic Chemistry at the University of Pardubice, Czech Republic, working in the research group of Prof. Filip Bureš. His research broadly focuses on the design, synthesis and characterization of functional molecular materials. His current research activities include the development of organic lithium salts for advanced battery electrolytes and the synthesis of molecular precursors for thin-film deposition, alongside other projects in synthetic and materials chemistry. He is currently undertaking a six-month research internship at the National Institute for Materials Science (NIMS) under the supervision of Dr. Jonathan Hill.

Metal selenides and tellurides and their corresponding thin films have attracted considerable attention in materials chemistry owing to their unique electronic and surface properties and their potential applications in advanced electronic and energy-related devices. Atomic layer deposition (ALD) provides a powerful approach for the fabrication of highly uniform and conformal thin films with precise thickness control, even on complex substrates. However, the selection of suitable molecular precursors for selenium- and tellurium-containing ALD processes remains rather limited.

In this work, a series of cyclic silyl chalcogenides containing two selenium or tellurium atoms was investigated as potential molecular precursors for ALD. These compounds were designed to combine key precursor requirements, including sufficient volatility, thermal stability and reactivity, while improving their stability towards air. The cyclic silyl derivatives 1–4 (Fig. 1) were synthesized in a straightforward one-step reaction of Li₂Se with the corresponding dichlorosilanes and were obtained in good yields. In addition, an alternative synthetic route to precursor 1 was developed using readily available elemental selenium as the starting material. The thermal properties of the prepared compounds were investigated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Finally, the synthesized precursors were successfully employed in ALD processes for the deposition of Sb₂Se₃,[1] MoSe₂[2] and MoTe₂[3] thin films.

1. V. M. Koch, J. Charvot, Y. Cao, C. Hartmann, R. G. Wilks, I. Kundrata, I. Mínguez-Bacho, D. Pokorný, E. Topraksal, A.-S. Smith, Ch. J. Brabec, F. Bureš, J. Bachmann, Chem. Mater. 34, 9392–9401 (2022), DOI: 10.1021/acs.chemmater.2c01550
2. J. Charvot, R. Zazpe, R. Krumpolec, J. Rodriguez-Pereira, D. Pavliňák, D. Pokorný, M. Klikar, V. Jelínková, J. M. Macák, F. Bureš, RSC Adv. 11, 22140–22147 (2021), DOI: 10.1039/d0ra10239c
3. R. Zazpe, H. Sopha, J. Charvot, R. Krumpolec, J. Rodriguez-Pereira, J. Michalička, J. Mistrík, D. Bača, M. Motola, F. Bureš, J. M. Macak, Appl. Mater. Today 23, 101017 (2021), DOI: 10.1016/j.apmt.2021.10101