Effect of chloride passivation on recombination dynamics in CdTe colloidal quantum dots

Espinobarro-Velazquez, D; Leontiadou, M; Page, RC; Califano, M; O'Brien, P; Binks, DJ

Abstract

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.

Citation

Espinobarro-Velazquez, D., Leontiadou, M., Page, R., Califano, M., O'Brien, P., & Binks, D. (2015). Effect of chloride passivation on recombination dynamics in CdTe colloidal quantum dots. ChemPhysChem, 16(6), 1239-1244. https://doi.org/10.1002/cphc.201402753

• Journal Article Type: Article
• Acceptance Date: Dec 17, 2014
• Online Publication Date: Jan 14, 2015
• Publication Date: Jan 14, 2015
• Deposit Date: Apr 2, 2019
• Publicly Available Date: Apr 2, 2019
• Journal: ChemPhysChem
• Print ISSN: 1439-4235
• Electronic ISSN: 1439-7641
• Publisher: Wiley
• Volume: 16
• Issue: 6
• Pages: 1239-1244
• DOI: https://doi.org/10.1002/cphc.201402753
• Publisher URL: https://doi.org/10.1002/cphc.201402753
• Related Public URLs: https://onlinelibrary.wiley.com/toc/14397641/2015/16/6
• Additional Information: Funders : Engineering and Physical Sciences Research Council (EPSRC);Mexican National Council on Science and Technology; Grant Number: EP/K008544/1; Grant Number: 308698