Theoretical and Experimental Chemistry, VoL 34, No. 5, 1998 PREPARATION AND OPTICAL PROPERTIES OF A NEW NANOSTRUCTURAL MATERIAL: SILVER-ION-DOPED CdS NANOPARTICLES IN SILICATE MATRICES N. P. Smirnova l, A. I. Kryukov 2, A. M. Eremenko l, Yu. A. Galagan ~, and S. Ya. Kuchmii z UDC 541.145 Porous silicate glasses containing cadmium sulfide nanopazticles doped with silver ions have been prepared; light absorption and luminescence have been investigated; and a new, general route for the creation of nanostructural materials of this type has been mapped out. Semiconductor particles with dimensions of a few nanometers and materials containing such particles, or materials built up from these particles, have unique properties that are different from those of macroscopic particles with the same chemical composition, or massive solids consisting of macroscopic particles, Nanostructural materials have unusual electronic, optical, photochemical, and adsorption properties; and, as demonstrated by studies performed in the last decade, such nanoparticles offer great promise for use in systems with nonlinear optical effects, and also in photocatalytic, electrochemical, photoelectrochemical, and certain other processes [1-4]. This situation, together with the importance of elucidating the fundamental aspects of the structure/property relationships, is the source of unflagging interest in the development of methods for obtaining and stabilizing semiconducting nanoparticles and nanostructural materials of various types. In the work reported here, we prepared cadmium sulfide nanoparticles doped with silver ions and incorporated into silicate matrices; also, we investigated the absorption and luminescence spectra of these materials. PREPARATION OF NANOSTRUCTURAL COMPOSITES CONSISTING OF A SEMICONDUCTOR AND A SILICATE MATRIX Two-component composites consisting of cadmium sulfide nanoparticles stabilized in silicate glasses were prepared by means of a sol-gel process that had already been used for this purpose [5, 6]. The process included the preparation of a silica hydrogel from tetraethoxysilane, this hydrogel containing Cd 2+ ions, impregnation of the hydrogel with an Na2S solution to precipitate CdS, and subsequent washing with distilled water and drying at 363 K. For one of the series of three-component composites containing silver and cadmium sulfides in a silicate glass, the synthesis was performed by an analogous procedure in which the original solution contained a mixture of Cd 2+ and Ag + ions that were subsequently coprecipitated by the action of Na2S. Another series of three-component materials was obtained by a different procedure: Finished samples of two-component composites were treated with an AgNO 3 solution to replace part of the Cd 2+ ions on the surface by Ag + ions. This reaction is possible in principle because of the lower solubility of silver sulfide (Ag2S solubility product 1.0-10-si, CdS solubility product 7.0.10 -2s [7]). It was established that the pores of the silicate matrix provide a route for the silver ions ~Institute of Surface Chemistry, National Academy of Sciences of Ukraine, 31 Prospect Nauki, Kiev 252022, Ukraine. ZL. V. Pisarzhevskii Institute of Physical Chemistry, National Academy of Sciences of Ukraine, 31 Prospect Nauki, Kiev 252039, Ukraine. Translated from Teoreticheskaya i I~ksperimental'naya Khimiya, Vol. 34, No. 5, pp. 297-301, September-October, 1998. Original article submitted June I, 1998. 272 0040-5760/98/3405-0272520.00 9 1999 Kluwer Academic/Plenum Publishers