Investigation of Factors That Affect Excited-State Lifetime Distribution of Dye-Sensitized Nanoparticle Films

摘要

We investigate the influence of potential determining ions and applied electric potentials on the excited-state lifetime distribution of sensitized TiO2 nanoparticle films by using time-correlated single photon counting to measure the time-dependent photoluminescence decay. The data are consistent with quenching by excited-state electron injection into localized semiconductor acceptor states that are distributed in energy. We show that the characteristic lifetime and the amount of dispersion in the lifetime distribution exhibit a strong correlation that is the same for all of the chemical additives and for the applied bias conditions. The universal nature of this correlation under conditions that affect the distribution of available acceptor states differently may be due to the exponential form of the TiO2 sub-bandgap density of states.