Effect of the thiol-thiolate equilibrium on the photophysical properties of aqueous CdSe/ZnS nanocrystal quantum dots

Sohee Jeong, Marc Achermann, Jagjit Nanda, Sergei Ivanov, Victor I. Klimov, Jennifer A. Hollingsworth

Research output: Contribution to journalArticle

197 Citations (Scopus)


We study the effect of thiols on the emission efficiency of aqueous CdSe/ZnS core/shell nanocrystal quantum dots (NQDs). We observe that the impact of thiol addition on emission quantum yields (QYs) is time-, concentration-, and pH-dependent. Further, we use a combination of time-resolved spectroscopic methods to determine the mechanism by which thiol addition can cause either increases or decreases in QYs. Specifically, through transient absorption measurements, we show that thiol addition can improve passivation of electron traps, increasing QYs at low thiol concentrations. Further, using nanosecond photoluminescence (PL), we observe that at higher thiol concentrations, hole traps are introduced that reduce PL QYs. Last, through a combination of pH-dependence and control studies (e.g., addition of 2-methyl thioethanol to an aqueous NQD solution and addition of dodecanethiol to a hexane NQD solution), we demonstrate that it is the ability of thiols in aqueous solution to generate thiolate that is the source of both favorable and adverse QY changes. Our results contribute to the understanding of the role of surface ligands, which is critical to the design of stable, high-quantum-yield, nonblinking NQDs.

Original languageEnglish
Pages (from-to)10126-10127
Number of pages2
JournalJournal of the American Chemical Society
Issue number29
Publication statusPublished - Jul 27 2005


ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

Cite this