Abrupt Size Partitioning of Multimodal Photoluminescence Relaxation in Monodisperse Silicon Nanocrystals

Samuel L. Brown, Joseph B. Miller, Rebecca J. Anthony, Uwe R. Kortshagen, Andrei Kryjevski, Erik K. Hobbie

Research output: Contribution to journalArticlepeer-review

25 Scopus citations

Abstract

Intrinsic constraints on efficient photoluminescence (PL) from smaller alkene-capped silicon nanocrystals (SiNCs) put limits on potential applications, but the root cause of such effects remains elusive. Here, plasma-synthesized colloidal SiNCs separated into monodisperse fractions reveal an abrupt size-dependent partitioning of multilevel PL relaxation, which we study as a function of temperature. Guided by theory and simulation, we explore the potential role of resonant phonon interactions with "minigaps" that emerge in the electronic density of states (DOS) under strong quantum confinement. Such higher-order structures can be very sensitive to SiNC surface chemistry, which we suggest might explain the common implication of surface effects in both the emergence of multimodal PL relaxation and the loss of quantum yield with decreasing nanocrystal size. Our results have potentially profound implications for optimizing the radiative recombination kinetics and quantum yield of smaller ligand-passivated SiNCs.

Original languageEnglish (US)
Pages (from-to)1597-1603
Number of pages7
JournalACS nano
Volume11
Issue number2
DOIs
StatePublished - Feb 28 2017

Bibliographical note

Funding Information:
E.K.H. acknowledges the support of the National Science Foundation (NSF) through CBET-1133135 and the US Department of Energy (DOE) through DE-FG36-08GO88160. R.J.A. and U.R.K. acknowledge primary support through the NSF under MRSEC Grant Nos. DMR-0819885 and DMR-1420013. A.K. acknowledges use of computational resources of the Center for Computationally Assisted Science and Technology (CCAST) at North Dakota State University and NERSC DE-AC02-05CH11231 for computational resources and financial support for method development from the NSF (Grant No. CHE-1413614).

Publisher Copyright:
© 2017 American Chemical Society.

Keywords

  • photoluminescence
  • quantum confinement
  • silicon nanocrystals
  • surface effects

How much support was provided by MRSEC?

  • Partial

Reporting period for MRSEC

  • Period 3

PubMed: MeSH publication types

  • Journal Article
  • Research Support, U.S. Gov't, Non-P.H.S.

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