Size-dependent valence and conduction band-edge energies of semiconductor nanocrystals

Jacek Jaroslaw Jasieniak, Marco Califano, Scott Edward Watkins

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583 Citations (Scopus)


Through the use of photoelectron spectroscopy in air (PESA), we investigate the size-dependent valence and conduction band-edge energies of CdSe, CdTe, PbS, and PbSe semiconductor quantum dots (QDs). The results are compared to those of previous studies, based on differing experimental methods, and to theoretical calculations based on k.p theory and state-of-the-art atomistic semiempirical pseudopotential modeling. To accurately map out the energy level landscapes of QDs as a function of size, the QDs must be passivated by comparable surface chemistries. This is highlighted by studying the effect of surface chemistry on the valence band-edge energy in an ensemble of 4.7 nm CdSe QDs. An energy level shift as large as 0.35 eV is observed for this system through modification of surface chemistry alone. This shift is significantly larger than the size-dependent valence band-edge shift that is observed when comparable surface chemistries are used.
Original languageEnglish
Pages (from-to)5888 - 5902
Number of pages15
JournalACS Nano
Issue number7
Publication statusPublished - 2011
Externally publishedYes

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