@article{5a0b0b9a12b1468e9ed3aec5700cc23a,
title = "Nanoscale Disorder Generates Subdiffusive Heat Transport in Self-Assembled Nanocrystal Films",
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.",
keywords = "Heat transport, self-assembled nanocrystals, subdiffusion, thermoreflectance, time-resolved microscopy, tortuosity",
author = "Utterback, {James K.} and Aditya Sood and Igor Coropceanu and Burak Guzelturk and Talapin, {Dmitri V.} and Lindenberg, {Aaron M.} and Ginsberg, {Naomi S.}",
note = "Funding Information: We acknowledge H. L. Weaver, J. G. Raybin, and J. C. Portner for helpful discussions. This work, including all stroboSCAT measurements and interpretation, were primarily funded through the “Photonics at Thermodynamic Limits” Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under award no. DE-SC0019140. Data interpretation was also supported by the SIMES Institute for Energy Sciences from the Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division, under contract DE-AC02-76SF00515. Sample preparation and characterization were supported by the Office of Basic Energy Sciences, the U.S. Department of Energy, under award no. DE-SC0019375. Simulations were performed in the Molecular Graphics and Computation Facility, College of Chemistry, UC Berkeley which is funded by NIH S10OD023532. J.K.U. acknowledges support from the Camille and Henry Dreyfus Foundation{\textquoteright}s Postdoctoral Program in Environmental Chemistry (data collection and initial simulations) and the Arnold O. Beckman Postdoctoral Fellowship in Chemical Sciences from the Arnold and Mabel Beckman Foundation (manuscript preparation). N.S.G. and D.V.T. also acknowledge Alfred P. Sloan Research Fellowships, David and Lucile Packard Foundation Fellowships for Science and Engineering, and Camille and Henry Dreyfus Teacher-Scholar Awards. Publisher Copyright: {\textcopyright} 2021 American Chemical Society.",
year = "2021",
month = apr,
day = "28",
doi = "10.1021/acs.nanolett.1c00413",
language = "English (US)",
volume = "21",
pages = "3540--3547",
journal = "Nano Letters",
issn = "1530-6984",
publisher = "American Chemical Society",
number = "8",
}