Transport Properties

Lide, David R.; Kehiaian, Henry V.

doi:10.1201/9781003067719-4

Cited by 80 publications

(115 citation statements)

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“…Therefore, for the sake of simplicity, each fit was performed using singular values for D eff and h , which represent a weighted average of the time-dependent values of these variables throughout the duration of anion exchange. These time-dependent changes in D eff are expected because of the evolving phase (Figures and S7) and/or morphology (Figure ) with respect to time during anion exchange . For example, as specific locations of the film are converted from Cu 2 O to CuO x S y , the effective solid-state diffusivity of sulfur in the Cu 2 O/CuO x S y composite will change.…”

Section: Resultsmentioning

confidence: 99%

Tunable Sulfur Incorporation into Atomic Layer Deposition Films Using Solution Anion Exchange

Lenef

Gayle

et al. 2023

Chem. Mater.

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Metal sulfide and oxysulfide thin films deposited by atomic layer deposition (ALD) are important functional materials for a range of applications including solar cells, catalysts, and electronic devices. However, ALD of sulfurcontaining films typically requires H 2 S, a toxic, corrosive, and flammable gas. To circumvent these challenges, we propose a method of tuning sulfur incorporation into ALD films by first growing a metal oxide, using CuO x as a model system, followed by a solution-phase sulfur anion-exchange process. By controlling the reaction time, solution molarity, and temperature, we demonstrate tunable sulfur incorporation into the films, which is described using a coupled reaction-diffusion model. The evolution of the film crystallinity, composition, and morphology was quantified as a function of the anion-exchange process parameters. Conformal anion exchange on a ZnO@TiO 2 @CuO core−shell− shell nanowire is shown, demonstrating the ability to maintain the conformality of the initial ALD process on high-aspect-ratio structures. Additionally, area-selective anion exchange was performed on micro-patterned substrates, illustrating a pathway toward device fabrication. Finally, the electrical properties of the converted films were evaluated, indicating a tunable reduction in sheet resistance of up to 4 orders of magnitude. In the future, the combination of ALD and anion-exchange chemistry can be used to incorporate sulfur without the need for H 2 S gas, while maintaining the atomically precise and conformal properties of the original ALD process.

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Section: Resultsmentioning

confidence: 99%

Tunable Sulfur Incorporation into Atomic Layer Deposition Films Using Solution Anion Exchange

Lenef

Gayle

et al. 2023

Chem. Mater.

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“…This deterioration of κ l could be ascribed to the enhanced phonon scattering at ZnSe nano-precipitates (Figure d). On the other hand, the excess Zn doping would strengthen the agglomeration of second-phase ZnSe, which has a higher κ l (∼16.0 W m –1 K –1 ) than the Ag 2 Se matrix, leading to the increase of κ l in the sample Ag 2 Se-0.01ZnSe. Thanks to the reduction of both κ e and κ l in the sample Ag 2 Se-0.005ZnSe, κ is reduced from ∼1.7 W m –1 K –1 of the undoped Ag 2 Se to ∼1.2 W m –1 K –1 at 383 K, a drop of about 0.5 W m –1 K –1 .…”

Section: Resultsmentioning

confidence: 99%

Ag Interstitial Inhibition and Phonon Scattering at the ZnSe Nano-Precipitates to Enhance the Thermoelectric Performance of Ag₂Se

Feng

Cheng

Liu

et al. 2023

ACS Appl. Energy Mater.

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Ag 2 Se-based thermoelectric (TE) materials have attracted significant attention recently due to their potential application near room temperature. Manipulating the stoichiometric ratio of Ag/Se and anion doping are usually used as effective approaches to enhance the TE properties. Here, we report a strategy to simultaneously enhance the power factor (PF) and reduce the thermal conductivity of Ag 2 Se by introducing ZnSe nano-precipitates. The excessive carrier concentration in the intrinsic Ag 2 Se is successfully reduced by the Ag interstitial inhibition due to the introduction of secondary-phase ZnSe nano-precipitates, thereby enhancing the PF up to a maximum value of ∼22.2 μW m −1 K −2 at 383 K and decreasing the electronic thermal conductivity from ∼1.2 to ∼0.8 W m −1 K −1 at 383 K. In addition, the phonon scattering at ZnSe nano-precipitates contributes to the reduction of lattice thermal conductivity from ∼0.5 to ∼0.4 W m −1 K −1 at 383 K. As a result, a high peak zT of ∼0.7 at 383 K and an average zT of 0.6 at 313−383 K are obtained in the sample Ag 2 Se-0.005ZnSe, which is one of the highest values amongst Ag 2 Se-based TE materials. This study could provide guidance to improve the TE properties of materials similar to Ag 2 Se.

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“…The enthalpies of gas-phase species, such as Δ H fC 2 H 4 , were taken from the previously built databases mentioned in Section . The enthalpies of reactions 9, 12, and 20 were obtained directly from reaction 6 through the C–H bond energy of hydrocarbon, e.g., normalΔ H 12 = normalΔ H 6 + ( Q H − C 2 H 3 − Q H − C H 3 ) where the C–H bond energies of methane Q H–CH 3 , ethylene Q H–C 2 H 3 , ethane Q H–C 2 H 5 , and propane Q H–C 3 H 7 are 438.9, 465.3, 423.0, and 416.5 kJ mol –1 , respectively …”

Section: Microkinetic Modeling Methodsmentioning

confidence: 99%

Improved Homogeneous–Heterogeneous Kinetic Mechanism Using a Langmuir–Hinshelwood-Based Microkinetic Model for High-Pressure Oxidative Coupling of Methane

Lundin

Obata

et al. 2023

Ind. Eng. Chem. Res.

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A comprehensive microkinetic mechanism for the oxidative coupling of methane (OCM) was developed by using the model La2O3–CeO2 catalyst at industrially relevant conditions up to 0.9 MPa and a gas hourly space velocity (GHSV) of ∼650,000 h–1. A Langmuir–Hinshelwood (LH)-based surface mechanism was coupled with gas-phase reactions (KAM 1-GS mechanism). The developed model was verified against low-pressure experimental results that minimized reaction exotherms. The improved LH mechanism, dividing the adsorption steps and surface reactions, provides flexible temperature and pressure dependencies to reproduce the experimental results across broad pressure conditions (0.010–0.80 MPa CH4). Specifically, the adsorption constant of C2H4 was found 20 times larger than that of C2H6 due to the π-electron-related high affinity of C2H4 to the surface. Additionally, high-pressure conditions were well described by considering the non-isothermal behavior from OCM reactions and heat dissipation from the reactor. The rate of production (ROP) results indicated that the enhanced unselective gas-phase reaction at high pressures caused the loss of C2–3 yield.

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Transport Properties

Cited by 80 publications

References 0 publications

Tunable Sulfur Incorporation into Atomic Layer Deposition Films Using Solution Anion Exchange

Tunable Sulfur Incorporation into Atomic Layer Deposition Films Using Solution Anion Exchange

Ag Interstitial Inhibition and Phonon Scattering at the ZnSe Nano-Precipitates to Enhance the Thermoelectric Performance of Ag₂Se

Improved Homogeneous–Heterogeneous Kinetic Mechanism Using a Langmuir–Hinshelwood-Based Microkinetic Model for High-Pressure Oxidative Coupling of Methane

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Transport Properties

Cited by 80 publications

References 0 publications

Tunable Sulfur Incorporation into Atomic Layer Deposition Films Using Solution Anion Exchange

Tunable Sulfur Incorporation into Atomic Layer Deposition Films Using Solution Anion Exchange

Ag Interstitial Inhibition and Phonon Scattering at the ZnSe Nano-Precipitates to Enhance the Thermoelectric Performance of Ag2Se

Improved Homogeneous–Heterogeneous Kinetic Mechanism Using a Langmuir–Hinshelwood-Based Microkinetic Model for High-Pressure Oxidative Coupling of Methane

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Ag Interstitial Inhibition and Phonon Scattering at the ZnSe Nano-Precipitates to Enhance the Thermoelectric Performance of Ag₂Se