The Radiation Peculiarities of Nanoscale SnO2 in a Porous Matrix

The features of luminescent properties of an ensemble of tin dioxide nanoparticles created inside various types of porous silicate glass matrices under various thermosynthesis conditions are studied. It was demonstrated that the highest intensity of radiative recombination is inherent to the system formed in finely porous silicate glass with residual silica gel in the pores. Silica gel in this case prevents the aggregation of SnO2 nanoparticles. For the all types of matrix, the luminescence energy is less than the fundamental SnO2 energy gap, which may indicate a trap-like luminescence character of these systems. It was established an occurrence of at least two types of recombination centers – acceptors close to the valence band. The luminescence intensity varies depending on the content of the precursor in the initial solution to obtain samples. Its maximum is observed at 5-7 % tin chloride in the initial solution. The specified method of ensemble creation corresponds to the greatest width of the luminescence spectral lines, which is inherent to the intensity of radiative recombination. The smallest width of the spectral line corresponds to large concentrations close to those at which the SnCl4 alcohol solution becomes a strong glass adhesive. At these concentrations the solution already begins to glue the silica gel particles, freeing up space for the further formation of aggregations after the thermosynthesis reaction. In this case, the aggregation is intensive. In ensembles of SnO2 nanoparticles created in porous glass depleted in silica gel, nonradiative recombination predominates due to leakage channels through aggregations formed during thermosynthesis in the absence of an insulating substance. The study results can be used to create luminescent gas sensors based on SnO2.