Phase Control of Cu2−xSe Nanoplates with Local Surface Plasmonic Resonance Synthesized by a Phosphine-free Process

Abstract

Self-doped copper-based selenides, typically for Cu2−xSe, are attracting great interest for many researchers due to their unique local surface plasmonic resonance (LSPR). To obtain highly-quality Cu2−xSe nanocrystals (NCs), a phosphine-free selenium precursor such as octadecene (ODE)-Se, oleylamine (OLA)-Se or oleic acid (OA)-Se are normally used. However, in order to effectively dissolve selenium powder in these phosphine-free reaction systems mentioned above, high dissolving or reacting temperatures are generally inevitable. In this work, we utilized a phosphine-free selenium precursor, which was prepared by dissolving selenium powder in a mixture solvent of oleylamine and 1-dodenethiol at room temperature, to successfully synthesize the pure-phase and monodispersed berzelianite Cu2−xSe nanoplates (NPs) with an obvious LSPR character at a relatively low temperature of 180 °C. In addition, just by changing the Cu/Se molar ratios of the precursor, klockmannite Cu0.87Se and CuSe NPs with different sizes we...