Silver nanocrystals obtained by the ionization of Ag−-ions in KCl

Site-Selective Excitation of “Exciplex Tuning” for Luminescent Nanoclusters of Dicyanoargentate(I) Ions Doped in Different Alkali Halide Crystals

“…Although luminescent exciplexes are well-known molecular entities in the photochemistry and photophysics of organic systems, they are less common in the inorganic literature . In addition, most reported inorganic exciplexes are not luminescent, although some luminescent Pt(II) exciplexes have been reported. , We have contributed to this field by discovering the optical phenomenon of “exciplex tuning” which is the tuning of the emission in Ag(CN) 2 − doped alkali halide crystals to various bands in the ultraviolet and visible regions with each band corresponding to a different [Ag(CN) 2 − ] excimer or exciplex. − , It should be noted that in contrast to pure complexes which exhibit bulk properties, doping these systems in alkali halide lattices essentially constitutes the creation of nanosystems , with the presence of dimers, trimers, and higher order oligomers in NaCl or KCl systems . A correlation between the luminescence and Raman bands for both pure and doped crystals containing the dicyanoargentate(I) and dicyanoaurate(I) ions provides the rationale for calling these doped systems nano .…”

Fractal characteristics of metal clusters self‐assembled in alkali halide matrices

“…Although the TEM image has a larger magnitude and the coalescence bonding can be observed, the resulting fractal dimensions were not altered by much. The differences in the fractal dimensions values might be due also to the fact that we are calculating a characteristic of a tridimensional structure [11,12] using a bidimensional image. There is a change in the fractal dimension values depending on the time of the thermal treatment and the temperature used, as expected.…”

“…Studies on Ag nanoclusters obtained in alkali halides by thermal treatments showed that spatially arranged structures are formed [10]. The same arrangement was found for Ag clusters obtained in KCl by thermal conversion of Ag --ions at 700, 645, 525 and 400 o C [11,12]. The obtaining in alkali halide matrices of the heavy metals nanostructures, that present a spatial arrangement, needs a detailed study regarding the way in which these structures are formed.…”

Tin nanoclusters obtained in potassium chloride by thermal annealing

“…The next step is the conversion in colloids of these negative ions, which appears in the whole range of temperatures, starting with 77 K up to 800 K. For the centers created at low temperature, a warm up until room temperature is enough to evidence different reactions between negative metal ions and the other defects. For the centers obtained over the room temperature, thermally annealing leads directly into metallic colloids [8][9][10][11]. In this paper we present for the first time the method of obtaining the nanoclusters of Sn in KCl crystals using step-by-step conversion of the defects produced during electrolytic coloration [12], presumably tin negative metal ions, followed by thermal annealing.…”

“…The optical absorption measurements were performed with a Perkin Elmer Lambda 45 spectrophotometer. For transmission electron microscopy (TEM) small pieces (2 x 2 x 1 mm 3 ) of freshly cleaved colored crystals were placed on a film covered microscope grid and carefully dissolved in distilled water [8]. TEM patterns show different behaviors between the samples with and without Ca.…”