Transition metal dichalcogenides (TMDCs) have been widely studied for various applications such as future electronic materials and catalysts. Among them, WSe2 has been especially interested due to its p-type semiconductor property, against n-type semiconductor of MoS2. However, large scale synthesis of WSe2 film has not been widely studied because the suitable precursor is not commercially available. In this study, we synthesized tungsten precursors containing selenium for facile formation of WSe2. Na2[WSe4] was synthesized by the reaction of W(CO)6 with Na2Se4. Sodium cation could be easily exchanged with tetraphenyl phosphonium (Ph4P+), cetyltrimethyl ammonium (cta+), and tetraethyl ammonium (Et4N+) cations. We have studied thermal decomposition and mechanism of (Cat+)2[WSe4] complexes, resulting in the formation of WSe2 by TG-MS. Nanoflakes of WSe2 were synthesized by solvo-thermal decomposition of (Cat+)2[WSe4] with oleylamine as capping ligand. No external reducing agent has been needed during the preparation of WSe2 from (Cat+)2[WSe4] due to the internal redox reaction between W and Se. Then we removed the impurities and increased the crystallinity through heat treatment.

Thermal decomposition of (Cat+)2[WSe4] for facile formation of WSe2

256th National Meeting (2018)

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