Cu2X(OH)3 (X = Cl−, NO3−): synthesis of nanoparticles and its application for room temperature deposition/printing of conductive copper thin-films

Abstract

Uniform Cu₂Cl(OH)₃ and Cu₂(NO₃)(OH)₃ nanoparticles are firstly prepared and characterized based on various analytical tools (i.e. DLS, SEM, XRD, FT-IR, UV-Vis, and DTA-TG). Accordingly, Cu₂Cl(OH)₃ and Cu₂(NO₃)(OH)₃ exhibit mean diameters of 51 nm and 37 nm, respectively. Both nanomaterials show a bright green colour with the maxima of absorption at 505 nm (Cu₂Cl(OH)₃) and 503 nm (Cu₂(NO₃)(OH)₃). Thermally Cu₂Cl(OH)₃ and Cu₂(NO₃)(OH)₃ decompose below 600 °C and 240 °C, respectively, to form CuO. In addition, as-prepared Cu₂Cl(OH)₃ and Cu₂(NO₃)(OH)₃ nanoparticles can be reduced to form copper metal at room temperature. While depositing/printing suspensions of the as-prepared nanoparticles in ethanol on silicon wafers, glass plates or paper, NaBH₄-driven reduction leads to highly conductive copper thin-films. Namely these thin-films exhibit sheet resistances of 3–10 Ω_□ and specific resistances of 1.3–4.3 × 10⁻³ Ω cm, which matches with the resistivity of bulk copper metal (1.7 × 10⁻³ Ω cm).