Multiexponential photoluminescence decay of blinking nanocrystal ensembles
Résumé
We investigate the relationship between the multiexponential photoluminescence (PL) dynamics of large nanocrystal (NC) ensembles and the intensity intermittency (blinking) characteristic of single NCs. A general model is developed and a simple fitting form derived for the analysis of PL decay curves allowing the extraction of both the intrinsic radiative recombination rate and an intensity intermittence parameter. The analysis is applied to the PL of a series of Si-NCs embedded in silicon oxide matrices yielding a good agreement between extracted and theoretical recombination rates. An excellent agreement is furthermore reported between the range of power-law exponents obtained and those previously determined through both single-NC experiments and current blinking mechanism theory. We suggest that a similar approach may well be fruitful in the analysis of time-resolved PL for a large variety of other carrier-confined materials.
