Time-Domain Thermoreflectance Measurements for Thermal Property Characterization of Nanostructures

Huxtable, Scott T.

doi:10.1142/9789814322843_0013

Cited by 3 publications

(4 citation statements)

References 40 publications

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“…The steady-state method and the transient hot-wire method can be used for bulk measurements. The 3ω method − and time-domain thermoreflectance (TDTR) − method can be used for thin film measurements. Recently, the TTG measurement has drawn attention as a new optical, in-plane thermal conductivity measurement. − This setup has advantages over conventional methods in that high space and time resolution are obtained with little sample preparation and simple data interpretation.…”

Section: Methodsmentioning

confidence: 99%

Thermal Switching of Thermoresponsive Polymer Aqueous Solutions

Tian

2017

ACS Macro Lett.

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Thermal switches are of great importance to thermal management in a wide variety of applications. However, traditional thermal switches suffer from being large and having slow transition rates. To overcome these limitations, we took advantage of abrupt second-order phase transitions in thermoresponsive polymer aqueous solutions to enable fast thermal switching. While thermoresponsive polymers have been widely studied for biomedical applications, their thermal switching capability has not been studied. In this work, we used poly(N-isopropylacrylamide) (PNIPAM) as a model system to demonstrate abrupt thermal conductivity changes of thermoresponsive polymer aqueous solutions across their transition temperatures by using a powerful approach, the transient thermal grating technique, which has high sensitivity. We observed a thermal switching ratio up to 1.15 in dilute PNIPAM aqueous solutions (up to 0.025 g/mL) across the transition. This work may provide new opportunities to engineer thermal switches using second-order phase transitions of thermoresponsive polymer aqueous solutions or abrupt higher-order phase transitions in general.

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Section: Methodsmentioning

confidence: 99%

Thermal Switching of Thermoresponsive Polymer Aqueous Solutions

Tian

2017

ACS Macro Lett.

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“…The time domain thermoreflectance (TDTR) − set up, as shown in Figure , relies on the fact that the reflectivity of aluminum has a measurable dependence on temperature. We used a Ti:sapphire mode-locked laser to produce a series of ∼100 fs optical pulses with a wavelength of 800 nm at a repetition rate of 80 MHz.…”

Section: Experimental Measurements With Tdtrmentioning

confidence: 99%

Effect of Crystallinity on Thermal Transport in Textured Lead Zirconate Titanate Thin Films

Varghese

Harikrishna

Huxtable

et al. 2014

ACS Appl. Mater. Interfaces

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We demonstrate the use of the time domain thermoreflectance (TDTR) technique towards understanding thermal transport in textured Pb(Zr,Ti)O3 (PZT) thin films grown by a sol-gel process on platinized silicon substrates. PZT films were grown with preferred crystallographic orientations of (100), (110), and (111). Grain orientation was controlled by manipulating the heterogeneous nucleation and growth characteristics at the interface between the film and the underlying Pt layer on the substrate. TDTR was used to measure both the PZT film thermal conductivity and the interface thermal conductance between the PZT and Pt as well as that between the PZT and an Al thermoreflectance layer evaporated on the PZT surface. We find a hierarchical dependence of thermal conductivity on the crystallographic orientation of the PZT films and observed differences in the thermal conductances between the Al-PZT and PZT-Pt interfaces for a varying degree of preferred orientations (100), (110), and (111). Thus, the technique based upon nanoscale thermal measurements can be used to delineate PZT samples with different crystallographic orientations. The thermal conductivities of the PZT films with different crystal orientations were in the range of 1.45-1.80 W m(-1) K(-1). The interface thermal conductance between the PZT and Pt layer was in the range of 30-65 MW m(-2) K(-1), while the conductance between the Al layer and PZT was in the range of 90-120 MW m(-2) K(-1). These interfacial conductances exhibit significant correlations to the texture of the PZT film and elemental concentration and densities at those interfaces.

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“…In this work, we study the k of polymer nanocomposites using the time-domain thermoreflectance (TDTR) technique to elucidate the confinement effects on k . By varying the molecular weight ( M w ) of polystyrene (PS) filled in a nanoporous organosilicate matrix with fixed pore size, we find that confinement enhances k .…”

mentioning

confidence: 99%

“…The film thicknesses of all the samples are over 500 nm, which are large enough to rule out the size effects on thermal conductivity. The k ’s of all of the samples are measured by the TDTR method, which is becoming one of the standard techniques for characterizing thermal properties of bulk and thin films using ultrafast lasers. − We prepared 1 or 2 samples with centimeter size for each type and performed TDTR measurements on multiple spots for each sample. Details of these measurements are described in the SI.…”

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confidence: 99%

Pore-Confined Polymers Enhance the Thermal Conductivity of Polymer Nanocomposites

Lionti

Magbitang

et al. 2021

ACS Macro Lett.

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Molecularly confined polymer fillers in nanopores were found to give superior mechanical properties of polymer nanocomposites. In this work, we study the thermal conductivity of such nanocomposites and unveil the effect of polymer confinement on thermal conductivity. Using the time-domain thermoreflectance method, we measure the cross-plane thermal conductivity of polymer nanocomposites that consist of polystyrene fillers confined within a nanoporous organosilicate matrix. Compared to unconfined bulk polystyrene fillers, we find that pore-confined polystyrene fillers enhance the thermal conductivity of the polymer nanocomposites. This enhancement is attributed to the better aligned and less entangled chains in the confined phase, where chain−chain phonon scatterings are reduced. Our work provides essential insights into the thermal conductivity of polymer nanocomposites for multifunctional thermal and mechanical applications.

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Time-Domain Thermoreflectance Measurements for Thermal Property Characterization of Nanostructures

Cited by 3 publications

References 40 publications

Thermal Switching of Thermoresponsive Polymer Aqueous Solutions

Thermal Switching of Thermoresponsive Polymer Aqueous Solutions

Effect of Crystallinity on Thermal Transport in Textured Lead Zirconate Titanate Thin Films

Pore-Confined Polymers Enhance the Thermal Conductivity of Polymer Nanocomposites

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