Near-unity quantum yields from chloride treated CdTe colloidal quantum dots

Page, RC; Espinobarro-Velazquez, D; Leontiadou, M; Smith, C; Lewis, EA; Haigh, SJ; Li, C; Radtke, H; Pengpad, A; Bondino, F; Magnano, E; Pis, I; Flavell, WR; O'Brien, P; Binks, DJ

Abstract

Colloidal quantum dots (CQDs) are promising materials for novel light sources and solar energy conversion. However, trap states associated with the CQD surface can produce non‐radiative charge recombination that significantly reduces device performance. Here a facile post‐synthetic treatment of CdTe CQDs is demonstrated that uses chloride ions to achieve near‐complete suppression of surface trapping, resulting in an increase of photoluminescence (PL) quantum yield (QY) from ca. 5% to up to 97.2 ± 2.5%. The effect of the treatment is characterised by absorption and PL spectroscopy, PL decay, scanning transmission electron microscopy, X‐ray diffraction and X‐ray photoelectron spectroscopy. This process also dramatically improves the air‐stability of the CQDs: before treatment the PL is largely quenched after 1 hour of air‐exposure, whilst the treated samples showed a PL QY of nearly 50% after more than 12 hours.

Citation

Page, R., Espinobarro-Velazquez, D., Leontiadou, M., Smith, C., Lewis, E., Haigh, S., …Binks, D. (2015). Near-unity quantum yields from chloride treated CdTe colloidal quantum dots. Small, 11(13), 1548-1554. https://doi.org/10.1002/smll.201402264

• Journal Article Type: Article
• Acceptance Date: Sep 14, 2014
• Online Publication Date: Oct 27, 2014
• Publication Date: Apr 1, 2015
• Deposit Date: Apr 1, 2019
• Publicly Available Date: Apr 1, 2019
• Journal: Small
• Print ISSN: 1613-6810
• Electronic ISSN: 1613-6829
• Publisher: Wiley
• Volume: 11
• Issue: 13
• Pages: 1548-1554
• DOI: https://doi.org/10.1002/smll.201402264
• Publisher URL: https://doi.org/10.1002/smll.201402264
• Related Public URLs: https://onlinelibrary.wiley.com/journal/16136829