Here in this contribution, blue and red luminescent 1-dodecanethiol (DT) terminated gold nanoclusters (AuNC) were prepared by a simple two-step synthesis route where the first step involved the surfactantfree synthesis of bare AuNC in N,N 0 -dimethylformamide (DMF) and the second step is the termination of the as-prepared bare AuNC by 1-dodecanethiol. The blue and red luminescent DT-terminated AuNC were isolated by a solvent-induced precipitation followed by an ultra-centrifugation technique. Both the bare AuNC and the blue and red luminescent DT-terminated AuNC exhibit stable photoluminescence and good solubility in various solvents. The photo-physical, electronic, structural, and morphological properties of the bare AuNC and the blue and red luminescent DT-terminated AuNC were examined by performing UV-Vis absorption spectroscopy, stationary and time-resolved PL spectroscopy, X-ray photoelectron spectroscopy (XPS), femtosecond transient absorption spectroscopy, Fourier-transform infrared spectroscopy (FTIR-ATR), and high-resolution transmission electron microscopy (HRTEM) experiments.

In this paper, we reported a very simple and environmentally friendly procedure for the synthesis of bright luminescent and nearly monodisperse Ag nanoclusters stabilized by a poly(N-vinylpyrrolidone) homopolymer.In this synthesis route acetonitrile or N,N-dimethylformamide (DMF) acts as both solvent and a reducing agent at their respective reflux temperatures. The as-prepared Ag clusters were found to be highly stable in various solvents as well as show nearly no changes in their emission intensity in solutions with different pH values and ionic strengths. Remarkably, the acetonitrile method predominantly produces blue emitting Ag clusters with a photoluminescence (PL) emission maximum at 424 nm (quantum yield 3.5%), whereas mainly blue-green emitting Ag clusters with the PL emission maximum at 450 nm (quantum yield 2.7%) were formed using the DMF method. The photo-physical, electronic, structural and morphological properties of the Ag clusters were investigated by performing UV/Vis absorption spectroscopy, stationary and time-resolved PL spectroscopy, X-ray photoelectron spectroscopy, femtosecond transient absorption spectroscopy, and transmission electron microscopy experiments.

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