Title: Study of the concentration quenching of tris(bipyridine) ruthenium(II) in the silicon dioxide particles

Abstract

A study was conducted of the change in the fluorescent properties of the luminescent dye tris (bipyridine) ruthenium (II) chloride (RuBpy) after its incorporation into microparticles of silicon dioxide. A decrease in concentration quenching in saturated solutions of RuBpy after incorporation into silicon dioxide, which occurred during the growth of microparticles in dye solutions, was studied. Objectives - find out whether the concentration quenching of the tris (bipyridine) ruthenium (II) chloride dye changes after its introduction into silica particles, and if it does, how. The methods used in the work process - synthesis of silicon dioxide particles according the Stöber method, measurements of absorption, fluorescence and excitation spectra of samples before and after growing the silicon dioxide, interpretation of the results obtained by the MO and coordination chemistry methods, acquiring images of the obtained particles using a scanning electron microscope. A series of samples were prepared representing the initial solutions of tetraethoxysilane (TEOS), RuBpy, and ammonia in an isopropyl alcohol: water mixture. In this case, the concentration of TEOS and ammonia was constant, while the concentration of the RuBpy increased from sample to sample. The concentration of the most saturated solution exceeded the concentration of the most dilute solution by almost 50 times. A noticeable concentration quenching of the initial solutions is noted, starting with a dye concentration equal to 4.14 × 10-5 mol / l. Following the work results, the following was established: 1. The sizes of the resulting particles increase in proportion to the increase in the concentration of the dye solution, all other things being equal; 2. The rate of conversion of the starting TEOS ester into silica particles increases in proportion to the increase in the concentration of the dye in the solution, all other things being equal; 3. The introduction of the dye into the nanoparticles of silicon dioxide makes it possible to reduce the concentration quenching by blocking one of the reasons for its formation - the formation of dye aggregates. 4. The fluorescence intensity of the dye solutions increases approximately 3 times after the growth of the silicon dioxide particles, which is associated with an increase in the total turbidity of the solutions and their transition into suspension.