Luminescence thermochromism in dicyanoargentate(I) ions doped in alkali halide crystals

Single crystals of [Ag(CN)(2)(-)]/NaCl and [Ag(CN)(2)(-)]/KCl show luminesc ence spectra that change drastically with temperature. The major luminescen ce band at 12 K is a UV emission at about 315 nm. Blue-green emissions in t he 400-520 nm region appear upon an increase in temperature to 80 K. A furt her increase in temperature results in the disappearance of the blue-green emissions and the appearance of a high-energy UV emission at about 290 nm. The color changes are reversible and represent a new example of luminescenc e thermochromism. A kinetic model is proposed to show the radiative and non radiative pathways at different temperatures. Highly resolved emission spec tra are obtained upon a careful selection of the excitation wavelength. Ind ividual peaks within the resolved emission bands are attributed to differen t geometrical isomers of a given *[Ag(CN)(2)(-)](n) cluster in the alkali h alide lattices. The wide range of luminescence energy, the strong luminesce nce at ambient temperature, and the control of the profile of the emission spectra by controlling the excitation wavelength are desired properties for the design of new solid-state photonic devices based bn the Ag(I) luminesc ence.