A study of the synthesis of bismuth tellurium selenide nanocompounds and procedures for improving their thermoelectric performance

Kim, Cham; Kim, Dong Hwan; Kim, Jong Sook; Han, Yoon Soo; Chung, Jong Shik; Kim, Ho-Young

doi:10.1016/j.jallcom.2011.07.040

Cited by 15 publications

(22 citation statements)

References 47 publications

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“…According to the equilibrium described in eq , S 2– ions react with the [Bi 3+ (HS–(CH 2 ) 2 –COO – ) x ] complex in the central compartment of the electrochemical cell, in the presence of Na + ions (eq ). After the electrolysis, the NaBiS 2 -MPA nanoparticle solution was transferred to a flask and the pH was adjusted to 10 . The heat treatment is crucial for the particle growth process; thus, during the heating at 90 °C, NaBiS 2 -MPA nanocrystals equilibrate with S 2– dissolved species (eq ), resulting in the formation of Bi 2 S 3 -MPA QDs (eq ) .…”

Section: Resultsmentioning

confidence: 99%

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Enhanced Visible-Light Photoelectrochemical Conversion on TiO₂ Nanotubes with Bi₂S₃ Quantum Dots Obtained by in Situ Electrochemical Method

Freitas

González-Moya

Soares

et al. 2018

ACS Appl. Energy Mater.

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A new greener strategy to incorporate Bi 2 S 3mercaptopropionic acid (MPA) quantum dots (QDs) onto TiO 2 nanotube (NT) films was developed, using in situ electrochemical synthesis with a graphite/sulfur powder macroelectrode (cathode) and cavity cell. Simultaneously, the obtained QDs were adsorbed on TiO 2 NTs, for the photoelectrochemical cell (PEC) assays. After the electrochemical synthesis, different thermal post-treatments were performed for growth and crystallization of obtained nanocrystals. The obtained TiO 2 −Bi 2 S 3 nanostructured composites were characterized by UV−vis, diffuse reflectance spectroscopy, X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Photoelectrochemical tests were carried out, where TiO 2 NTs/Bi 2 S 3 QDs with 15 min post-treatment at 90 °C presented a greater photocurrent density, when irradiated with visible light (427−655 nm region, 10 mW.cm −2 ) and compared to pristine TiO 2 NTs. Such performance can be attributed to the synergetic effect caused by the good interface between TiO 2 NTs/Bi 2 S 3 QDs, promoted by the electrochemical method of synthesis employed. The proof of concept evidenced in this work can be potentially extended for the sensitization of TiO 2 NTs with other semiconductors for PEC hydrogen generation and solar cell applications.

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Section: Resultsmentioning

confidence: 99%

“…nanoparticle solution was transferred to a flask and the pH was adjusted to 10 36. The heat treatment is crucial for the particle growth process; thus, during the heating at 90 °C, NaBiS 2 -MPA nanocrystals equilibrate with S 2− dissolved species (eq 7), resulting in the formation of Bi 2 S 3 -MPA QDs (eq 8) .…”

mentioning

confidence: 99%

Enhanced Visible-Light Photoelectrochemical Conversion on TiO₂ Nanotubes with Bi₂S₃ Quantum Dots Obtained by in Situ Electrochemical Method

Freitas

González-Moya

Soares

et al. 2018

ACS Appl. Energy Mater.

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“…Because we employed a metal precursor (i.e., Bi(NO 3 ) 3 ) for synthesizing the nanocompound, the actual amount of metal in the precursor could be different from the theoretical amount of metal according to the precursor stoichiometry . In other words, we might obtain a final product with a somewhat different stoichiometric ratio compared to the intended ratio.…”

Section: Resultsmentioning

confidence: 99%

“…Research into a BiTe-based nanocompound has mostly been performed on the p-type semiconductor, Bi x Sb 2– x Te 3 , because it basically exhibits a high power factor. ,, The Bi x Sb 2– x Te 3 nanocompound can even exhibit a low thermal conductivity, and thus the p-type nanocompound has an excellent ZT value, up to 1.4 . Both p-type and n-type materials are required to constitute thermoelectric modules, but an n-type BiTe nanocompounds still show relatively low ZT values, likely because of their low power factors . This is why researchers should develop an n-type BiTe nanocompound having a high thermoelectric performance.…”

Section: Introductionmentioning

confidence: 99%

Significant Enhancement in the Thermoelectric Performance of a Bismuth Telluride Nanocompound through Brief Fabrication Procedures

Kim

et al. 2012

ACS Appl. Mater. Interfaces

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A binary BiTe nanocompound for thermoelectric applications was prepared via a water-based chemical reaction under atmospheric conditions. We attempted to increase the carrier mobility of the nanocompound by adopting a post-thermal treatment consisting of calcination and reduction at different temperatures. We also tried to control the carrier density of the compound by adjusting the stoichiometry of the atomic constituents. We measured other transport properties (i.e., electrical resistivity, Seebeck coefficient, and thermal conductivity) and observed how these properties were affected by both the carrier mobility and the carrier density. We derived the thermoelectric performance, as captured by the figure of merit (ZT), from the transport properties and discussed the effect of such properties on the ZT value. The nanocompound exhibited a very competent ZT value (0.91 at 100 °C), which is one of the best thermoelectric performances of chemically synthesized BiTe materials.

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“…Functionally graded materials (FGMs) are engineered materials where properties are varied spatially either continuously or a step-by-step (segmented) fashion throughout the volume of the material. − Spatial control through composition, microstructure, and orientation can tune local properties across the FGM . Implementation of the functional grading principles offers an opportunity of increasing the efficiency of thermoelectric devices for power generation or cooling by employing appropriate distribution of n and microstructure. − The effectiveness of FGMs has been exclusively investigated with inorganic thermoelectric materials (e.g., Bi 2 Te 3 and PbTe). ,, For perspective, a wide operating temperature range (up to ca. 1000 K) for power generation through inorganic materials leads to thermoelectric properties to be a strong function of temperature .…”

Section: Introductionmentioning

confidence: 99%

Leveraging Sequential Doping of Semiconducting Polymers to Enable Functionally Graded Materials for Organic Thermoelectrics

Dong

Grocke

et al. 2020

Macromolecules

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With the ability to modulate electronic properties through molecular doping coupled with ease in processability, semiconducting polymers are at the forefront in enabling organic thermoelectric devices for thermal energy management. In contrast to uniform thermoelectric material properties, an alternative route focuses on functionally graded materials (FGMs) where one spatially controls and optimizes transport properties across the length of a thermoelectric material. While primarily studied in the context of inorganic materials, the concept of FGMs for organic thermoelectrics has not been explored. Herein, we introduce how molecular doping of semiconducting polymers enables spatial compositional control of thin-film FGMs. Specifically, we use sequential vapor doping of poly[2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene] (PBTTT) with the small molecule acceptor 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ) to fabricate the simplest form of FGMsdouble-segmented thin films. The two thin-film segments are of equal length (7.5 mm) but each set to different doping levels. Our study focuses on understanding the thermoelectric properties (Seebeck coefficient, α, and electronic conductivity, σ) and structural properties (through X-ray scattering, UV–vis–NIR spectroscopy, and Raman spectroscopy) within and across the two segments. We observe the presence of a small diffuse interfacial region of 0.5–1 mm between the two segments where the doping level and transport properties vary continuously. Despite the diffuse interface, the measured α across the two segments is simply the average of α within each segment. Importantly, this experimental result is consistent with reported mathematical models describing the spatial average of α in graded thermoelectric materials. Our results demonstrate the facile fabrication and characterization of functionally graded organic thermoelectric materials, providing guidelines for further development on more complex FGMs.

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A study of the synthesis of bismuth tellurium selenide nanocompounds and procedures for improving their thermoelectric performance

Cited by 15 publications

References 47 publications

Enhanced Visible-Light Photoelectrochemical Conversion on TiO₂ Nanotubes with Bi₂S₃ Quantum Dots Obtained by in Situ Electrochemical Method

Enhanced Visible-Light Photoelectrochemical Conversion on TiO₂ Nanotubes with Bi₂S₃ Quantum Dots Obtained by in Situ Electrochemical Method

Significant Enhancement in the Thermoelectric Performance of a Bismuth Telluride Nanocompound through Brief Fabrication Procedures

Leveraging Sequential Doping of Semiconducting Polymers to Enable Functionally Graded Materials for Organic Thermoelectrics

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A study of the synthesis of bismuth tellurium selenide nanocompounds and procedures for improving their thermoelectric performance

Cited by 15 publications

References 47 publications

Enhanced Visible-Light Photoelectrochemical Conversion on TiO2 Nanotubes with Bi2S3 Quantum Dots Obtained by in Situ Electrochemical Method

Enhanced Visible-Light Photoelectrochemical Conversion on TiO2 Nanotubes with Bi2S3 Quantum Dots Obtained by in Situ Electrochemical Method

Significant Enhancement in the Thermoelectric Performance of a Bismuth Telluride Nanocompound through Brief Fabrication Procedures

Leveraging Sequential Doping of Semiconducting Polymers to Enable Functionally Graded Materials for Organic Thermoelectrics

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Product

Resources

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Enhanced Visible-Light Photoelectrochemical Conversion on TiO₂ Nanotubes with Bi₂S₃ Quantum Dots Obtained by in Situ Electrochemical Method

Enhanced Visible-Light Photoelectrochemical Conversion on TiO₂ Nanotubes with Bi₂S₃ Quantum Dots Obtained by in Situ Electrochemical Method