Potential-modulated attenuated total reflectance characterization of charge injection processes in monolayer-tethered CdSe nanocrystals

Zeynep Ozkan Araci, Clayton R. Shallcross, Neal R. Armstrong, S. Scott Saavedra

Research output: Contribution to journalArticle

22 Scopus citations

Abstract

Reversible electron injection into pyridine-capped CdSe nanocrystals (pyr-CdSe NCs), tethered to indium-tin oxide (ITO) substrates using mercaptoalkylcarboxylic acids, is characterized using attenuated total reflectance (ATR) spectroelectrochemistry on a planar waveguide. The sensitivity of this technique provides for characterization of redox processes in submonolayer films of pyr-CdSe NCs. Optically determined onset potentials for electron injection, measured as bleaching/recovery of the exciton absorption band, provide estimates for the conduction band edge (ECB). Potential-modulated attenuated total reflectance (PM-ATR), in which the in-phase and out-of-phase reflectance response is measured as a function of modulation frequency, provides estimates for rates of electron injection. These apparent rate constants are found to be nearly independent of tether chain length, suggesting that communication between tethered NCs and electrochemically less active (i.e., less conductive) regions on the ITO surface is rate-limiting.

Original languageEnglish (US)
Pages (from-to)1900-1905
Number of pages6
JournalJournal of Physical Chemistry Letters
Volume1
Issue number12
DOIs
StatePublished - Jun 17 2010

ASJC Scopus subject areas

  • Materials Science(all)
  • Physical and Theoretical Chemistry

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