Thin-film differential scanning nanocalorimetry: heat capacity analysis

Efremov, Mikhail Yu.; Olson, E. A.; Zhang, M.; Lai, S. L.; Schiettekatte, F.; Zhang, Z.S.; Allen, L. H.

doi:10.1016/j.tca.2003.08.019

Cited by 110 publications

(66 citation statements)

References 15 publications

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“…Heat Capacity Analysis. Methods for heat capacity calculation using voltage and current experimental data are discussed in detail in ref 9. To obtain general calorimetric data for the samples in this investigation, the more accurate "main" method with three corrections 9 is used.…”

Section: Introductionmentioning

confidence: 99%

Probing Glass Transition of Ultrathin Polymer Films at a Time Scale of Seconds Using Fast Differential Scanning Calorimetry

et al. 2004

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Ultrasensitive, thin-film, differential scanning calorimetry is used to determine the glasstransition temperature of 3-400 nm thick, spin-cast films of polystyrene, poly (2-vinyl pyridine), and poly (methyl methacrylate) on a platinum surface. The technique used here is modified to characterize the glass transition over a time scale of seconds rather than milliseconds. No appreciable dependence of the glass-transition temperature on thickness is observed over the entire range used. The results are discussed in comparison with previous calorimetric measurements, characterized by the glass-transition time scale of milliseconds.

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Section: Introductionmentioning

confidence: 99%

Probing Glass Transition of Ultrathin Polymer Films at a Time Scale of Seconds Using Fast Differential Scanning Calorimetry

et al. 2004

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“…IIID) would require the temperature oscillations to vanish everywhere in the sensor over an entire window to be detected. We assert that 48 the longer time averaging provided by a lower frequency reduces the peak value of the heat capacity signal. C. The effect of scanning rate on the AC measurements measurements over a wide range of heating rates.…”

Section: B the Effect Of Frequency On The Ac Measurementmentioning

confidence: 79%

Scanning AC Nanocalorimetry and Its Applications

Xiao

Vlassak

2016

Fast Scanning Calorimetry

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This thesis presents an AC nanocalorimetry technique that enables calorimetry measurements on very small quantities of materials over a wide range of scanning rates (from isothermal to 3×10^3 K/s), temperatures (up to 1200 K), and environments. Such working range bridges the gap between traditional scanning calorimetry of bulk materials and nanocalorimetry. The method relies on a micromachined nanocalorimeter with negligible thermal lags between heater, thermometer, and sample. The ability to perform calorimetry measurements over such a broad range of scanning rates makes it an ideal tool to characterize the kinetics of phase transformations, reactions at elevated temperatures or to explore the behavior of materials far from equilibrium. We By combining scanning DC and AC nano-calorimetry techniques, we study the nucleation behavior of undercooled liquid Bi at cooling rates ranging from 10^1 to 10^4 K/s. Upon initial melting, the Bi thin-film sample breaks up into isolated islands. The number of islands in a typical sample is sufficiently large that highly repeatable nucleation behavior is observed, despite the stochastic nature of the nucleation process.We establish a data reduction technique to evaluate the nucleation rate from DC and AC calorimetry results. The results show that the driving force for the nucleation of melted Bi is well described by classical nucleation theory over a wide range of cooling rates. The proposed technique provides a unique and efficient way to examine nucleation kinetics v with cooling rates over several orders of magnitude. The technique is quite general and can be used to evaluate reaction kinetics in other materials.Lastly, we apply the scanning AC nanocalorimetry technique to study solid-gas phase reactions by measuring the change in heat capacity of a sample during reaction. We apply this approach to evaluate the oxidation kinetics of thin-film samples of zirconium in air. The results confirm parabolic oxidation kinetics with an activation energy of 0.59±0.03 eV. The nano-calorimetry measurements were performed using a device that contains an array of micromachined nano-calorimeter sensors in an architecture designed for combinatorial studies. We demonstrate that the oxidation kinetics can be quantified using a single sample, thus enabling high-throughput mapping of the composition-dependence of the reaction rate.vi

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“…Electrical and thermal contact resistances expressed as specific values R C_i-j and R th_i-j are assumed at interfaces between adjacent layers indexed by i and j, with (j=i+ 1). Classical thermoelectric transport model, which neglects electron-phonon nonequilibrium effects, is developed by assuming, that the thickness of thermoelectric film is much larger than phononelectron thermalization length [25]. Under these conditions, thermoelectric transport in the probe, electrode, and sample is considered one-dimensional.…”

Section: Transient Harman Technique-analytical Modelmentioning

confidence: 99%

“…(42) for a range of specific thermal contact resistances. Electrical resistance of contact was assumed to be equal to theoretical limit predicted for electrical boundary resistance between Bi 2 Te 3 and metal electrode [25]. Direction of electrical current was chosen such, that the sample surface undergoes Peltier cooling.…”

Section: Thermoelectrics For Power Generation -A Look At Trends In Thmentioning

confidence: 99%

See 1 more Smart Citation

Novel Measurement Methods for Thermoelectric Power Generator Materials and Devices

Taylor¹,

Wilson²,

Maddux³

et al. 2016

Thermoelectrics for Power Generation - A Look at Trends in the Technology

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Thermoelectric measurements are notoriously challenging. In this work, we outline new thermoelectric characterization methods that are experimentally more straightforward and provide much higher accuracy, reducing error by at least a factor of 2. Specifically, three novel measurement methodologies for thermal conductivity are detailed: steadystate isothermal measurements, scanning hot probe, and lock-in transient Harman technique. These three new measurement methodologies are validated using experimental measurement results from standards, as well as candidate materials for thermoelectric power generation. We review thermal conductivity measurement results from new halfHeusler (ZrNiSn-based) materials, as well as commercial (Bi,Sb) 2 (Te,Se) 3 and mature PbTe samples. For devices, we show characterization of commercial (Bi,Sb) 2 (Te,Se) 3 modules, precommercial PbTe/TAGS modules, and new high accuracy numerical device simulation of Skutterudite devices. Measurements are validated by comparison to wellestablished standard reference materials, as well as evaluation of device performance, and comparison to theoretical prediction obtained using measurements of individual properties. The new measurement methodologies presented here provide a new, compelling, simple, and more accurate means of material characterization, providing better agreement with theory.

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Thin-film differential scanning nanocalorimetry: heat capacity analysis

Cited by 110 publications

References 15 publications

Probing Glass Transition of Ultrathin Polymer Films at a Time Scale of Seconds Using Fast Differential Scanning Calorimetry

Probing Glass Transition of Ultrathin Polymer Films at a Time Scale of Seconds Using Fast Differential Scanning Calorimetry

Scanning AC Nanocalorimetry and Its Applications

Novel Measurement Methods for Thermoelectric Power Generator Materials and Devices

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