Chinese Journal of Luminescence
Probability Distribution of Luminescence Lifetime of Nanometer Particles Containing Luminescent Ions Embedded in Media
Chang‐Kui Duan
Abstract
Spontaneous emission rate is not only affected by the properties of the material itself, but also depends on the dielectric properties of the surrounding media. Recently, some work has been carried out to study the dependence of spontaneous emission rates of the luminescent-ion-containing nanometer particles on the refractive index of the media. Based on the free distribution of nanometer particles in media, the pro-bability density of luminescent lifetime is analyzed. Since nanometer particles distribute freely in media, the number of nanometer particles in a given volume surrounding the luminescent center obeys the Poission distribution. The local relative refractive index nr, which is the ratio of media effective refractive index to particle refractive index, is affected by the particle number of nanoparticles within a sphere of radius half of the radiative wavelength. The probability density function of nr can be obtained according to the dependence of nr on the particle number. Based on the relation between nr and luminescence lifetime, the analytical form of probability density function of lifetime is obtained. A calculation has been done based on the parameters given in Meltzer's experiment (Eu3+ doped Y2O3 in methanol). The result shows that the relative fluctuation of luminescence lifetime is too small to be observed. However, with increasing size of nanometer particles or density of nanometer particles, the relative fluctuation of lifetime increases greatly and could be observed.