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This content will become publicly available on October 27, 2014

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

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. We find 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.
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [1] ;  [1] ;  [3] ;  [3] ;  [3] ;  [1] ;  [1] ;  [1]
  1. Univ. of Manchester, Manchester (United Kingdom)
  2. Vanderbilt Univ., Nashville, TN (United States)
  3. IOM CNR, Lab. Nazionale TASC, Basovizza (Italy)
Publication Date:
OSTI Identifier:
1237102
Grant/Contract Number:
EP/K008544/1; 226716; HDTRA1-12-1-0013
Type:
Published Article
Journal Name:
Small
Additional Journal Information:
Journal Volume: 11; Journal Issue: 13; Journal ID: ISSN 1613-6810
Publisher:
Wiley
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); Engineering and Physical Sciences Research Council (EPSRC); European Community’s Seventh Framework Programme
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; nanocrystalline materials; colloidal quantum dots; photoluminescence; photoelectron spectroscopy; transmission electron microscopy; passivation