@Article{TheJPhysChemC_116_9300, author = {L.R. Bradshaw and A. Hauser and E.J. McLaurin and D.R. Gamelin}, title = {{Luminescence Saturation via Mn$^{2+}${\frac{ }{ }}Exciton Cross Relaxation in Colloidal Doped Semiconductor Nanocrystals}}, journal= {The J. Phys. Chem. C}, ISSN = {1932-7447}, volume= {116}, number= {16}, pages = {9300-9310}, url = {http://pubs.acs.org/doi/abs/10.1021/jp300765y}, eprint= {http://www.unige.ch/sciences/chifi/publis/refs_pdf/ref01291.pdf}, doi= {10.1021/jp300765y}, abstract = {{Colloidal Mn$^{2+}$-doped semiconductor nanocrystals such as Mn$^{2+}$:ZnSe have attracted broad attention for potential applications in phosphor and imaging technologies. Here, we report saturation of the sensitized Mn$^{2+}$ photoluminescence intensity at very low continuous-wave (CW) and quasi-CW photoexcitation powers under conditions that are relevant to many of the proposed applications. Time-resolved photoluminescence measurements and kinetic modeling indicate that this saturation arises from an Auger-type nonradiative cross relaxation between an excited Mn$^{2+}$ ion and an exciton within the same nanocrystal. A lower limit of k = 2 × 10$^{10}$ s$^{{\frac{ }{ }}1}$ is established for the fundamental rate constant of the Mn$^{2+}$($^{4}$T$_1$)-exciton cross relaxation.}}, year = {2012} }