Ultrafast charge dynamics in trap-free and surface-trapping colloidal quantum dots

Smith, CT; Leontiadou, M; Page, R; O'Brien, P; Binks, DJ

Abstract

Ultrafast transient absorption spectroscopy is used to study subnanosecond charge dynamics in CdTe colloidal quantum dots. After treatment with chloride ions, these can become free of surface traps that produce nonradiative recombination. A comparison between these dots and the same dots before treatment enables new insights into the effect of surface trapping on ultrafast charge dynamics. The surface traps typically increase the rate of electron cooling by 70% and introduce a recombination pathway that depopulates the conduction band minimum of single excitons on a subnanosecond timescale, regardless of whether the sample is stirred or flowed. It is also shown that surface trapping significantly reduces the peak bleach obtained for a particular pump fluence, which has important implications for the interpretation of transient absorption data, including the estimation of absorption cross‐sections and multiple exciton generation yields.

Citation

Smith, C., Leontiadou, M., Page, R., O'Brien, P., & Binks, D. (2015). Ultrafast charge dynamics in trap-free and surface-trapping colloidal quantum dots. Advanced Science, 2(10), 1500088. https://doi.org/10.1002/advs.201600165

• Journal Article Type: Article
• Acceptance Date: May 22, 2015
• Online Publication Date: Jun 24, 2015
• Publication Date: Jun 24, 2015
• Deposit Date: Apr 2, 2019
• Publicly Available Date: Apr 2, 2019
• Journal: Advanced Science
• Publisher: Wiley Open Access
• Volume: 2
• Issue: 10
• Pages: 1500088
• DOI: https://doi.org/10.1002/advs.201600165
• Publisher URL: https://doi.org/10.1002/advs.201600165
• Related Public URLs: https://onlinelibrary.wiley.com/journal/21983844
• Additional Information: Access Information : The correction to the original publication (https://doi.org/10.1002/advs.201500088) was published online on 13th July 2016.