Espinobarro-Velazquez Daniel, Leontiadou Marina A, Page Robert C, Califano Marco, O'Brien Paul, Binks David J
School of Physics and Astronomy and Photon Science Institute, University of Manchester, Oxford Road, Manchester M13 9PL (UK).
Chemphyschem. 2015 Apr 27;16(6):1239-44. doi: 10.1002/cphc.201402753. Epub 2015 Jan 14.
Colloidal quantum dots (CQDs) can be used in conjunction with organic charge-transporting layers to produce light-emitting diodes, solar cells and other devices. The efficacy of CQDs in these applications is reduced by the non-radiative recombination associated with surface traps. Here we investigate the effect on the recombination dynamics in CdTe CQDs of the passivation of these surface traps by chloride ions. Radiative recombination dominates in these passivated CQDs, with the radiative lifetime scaling linearly with CQD volume over τr =20-55 ns. Before chloride passivation or after exposure to air, two non-radiative components are also observed in the recombination transients, with sample-dependent lifetimes typically of less than 1 ns and a few ns. The non-radiative dynamics can be explained by Auger-mediated trapping of holes and the lifetimes of this process calculated by an atomistic model are in agreement with experimental values if assuming surface oxidation of the CQDs.
胶体量子点（CQDs）可与有机电荷传输层结合使用，以制造发光二极管、太阳能电池和其他器件。与表面陷阱相关的非辐射复合会降低CQDs在这些应用中的效能。在此，我们研究了氯离子对这些表面陷阱的钝化作用对碲化镉CQDs中复合动力学的影响。在这些经过钝化的CQDs中，辐射复合占主导地位，辐射寿命在τr = 20 - 55 ns范围内随CQD体积呈线性变化。在氯化物钝化之前或暴露于空气中之后，在复合瞬态中还观察到两个非辐射成分，其样品依赖的寿命通常小于1 ns和几纳秒。非辐射动力学可以用俄歇介导的空穴俘获来解释，如果假设CQDs发生表面氧化，通过原子模型计算的这个过程的寿命与实验值相符。
