Nanoscale Disorder Generates Subdiffusive Heat Transport in Self-Assembled Nanocrystal Films

James K. Utterback, Aditya Sood, Igor Coropceanu, Burak Guzelturk, Dmitri V. Talapin, Aaron M. Lindenberg, Naomi S. Ginsberg

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

Investigating the impact of nanoscale heterogeneity on heat transport requires a spatiotemporal probe of temperature on the length and time scales intrinsic to heat navigating nanoscale defects. Here, we use stroboscopic optical scattering microscopy to visualize nanoscale heat transport in disordered films of gold nanocrystals. We find that heat transport appears subdiffusive at the nanoscale. Finite element simulations show that tortuosity of the heat flow underlies the subdiffusive transport, owing to a distribution of nonconductive voids. Thus, while heat travels diffusively through contiguous regions of the film, the tortuosity causes heat to navigate circuitous pathways that make the observed mean-squared expansion of an initially localized temperature distribution appear subdiffusive on length scales comparable to the voids. Our approach should be broadly applicable to uncover the impact of both designed and unintended heterogeneities in a wide range of materials and devices that can affect more commonly used spatially averaged thermal transport measurements.

Original languageEnglish (US)
Pages (from-to)3540-3547
Number of pages8
JournalNano Letters
Volume21
Issue number8
DOIs
StatePublished - Apr 28 2021
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Mechanical Engineering
  • Bioengineering
  • General Chemistry
  • General Materials Science

Keywords

  • Heat transport
  • self-assembled nanocrystals
  • subdiffusion
  • thermoreflectance
  • time-resolved microscopy
  • tortuosity

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