EIS characterization of aging and humidity-related behavior of Bi2Se3 films of different morphologies

Erts, Donāts; Katkevics, J; Sjomkane, Maija; Andzane, Jana; Šarakovskis, Anatolijs; Šmits, Krišjānis; Vīksna, Artūrs; Rublova, Yelyzaveta; Meija, Raimonds

doi:10.1016/j.nanoso.2022.100847

Cited by 8 publications

(9 citation statements)

References 31 publications

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“…EIS measurements were performed using the custom system reported in detail elsewhere. 19 The system allowed regulation of the nitrogen gas relative humidity (RH) from 5 to 90%, with a gas flow of up to 1.0 L•min −1 . The relative error in measuring humidity was ±2%.…”

Section: Methodsmentioning

confidence: 99%

Thermoelectric Properties of Bare and Nonconductive Polymer-Encapsulated Sb₂Te₃-MWCNT Hybrid Networks and Their Application in Flexible Heat-to-Power Conversion Devices

Andzane,

Spalva,

Katkevics

et al. 2023

ACS Appl. Energy Mater.

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In this work, thermoelectrical properties of flexible thermoelectric films fabricated by the encapsulation of multiwalled carbon nanotube-antimony telluride (Sb2Te3-MWCNT) hybrid networks with different Sb2Te3:MWCNT mass ratios in polydimethylsiloxane (PDMS) were studied for the first time. Sb2Te3-MWCNTs were synthesized by the direct physical vapor deposition of Sb2Te3 nanostructures on the MWCNT network, spray-coated on a flexible polyimide substrate, and encapsulated in PDMS using a drop-casting technique. A study of electrical and thermoelectric properties of Sb2Te3-MWCNT hybrid networks before and after encapsulation revealed that encapsulation effectively preserves the properties of the hybrid networks and improves their durability under repetitive bending, showing deviations in resistance not exceeding 0.5% of the initial value during 100 repetitive bending cycles down to a 3 mm radius. Encapsulated Sb2Te3-MWCNT networks showed the thermoelectric power factor (PF) reaching 9.5 μW·m–1 K–2, which is ∼3 orders of magnitude higher than the values of PF showed previously by the composites prepared by mechanical mixing of the Sb2Te3-MWCNT hybrid networks with a nonconductive polymer. PDMS-encapsulated Sb2Te3-MWCNT hybrid networks in combination with previously reported PVA-encapsulated Bi2Se3-MWCNT hybrid networks were used to assemble 4-leg-pair flexible thermoelectric generators, where leg pairs were connected in series or parallel. Both types of generators showed stable performance with different external resistances connected in the circuit and reached an output power of ∼7–10 μW·cm–2 and an output current of ∼1–5 μA. These parameters illustrate the significant potential of the presented PDMS-encapsulated Sb2Te3-MWCNT hybrid networks as building blocks for custom flexible devices for micro- and nanopower applications.

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Section: Methodsmentioning

confidence: 99%

Thermoelectric Properties of Bare and Nonconductive Polymer-Encapsulated Sb₂Te₃-MWCNT Hybrid Networks and Their Application in Flexible Heat-to-Power Conversion Devices

Andzane,

Spalva,

Katkevics

et al. 2023

ACS Appl. Energy Mater.

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“…Overall, the total impedance magnitude was found to be increasing with the increase of the RH level, which is consistent with the behavior previously observed for the partly disordered Bi 2 Se 3 thin films. [ 20 ] For the RH ≤ 60%, the humidity‐related changes of the impedance of the sample were reversible (Figure 6, colored rhombs) and no visual changes in the sample morphology were observed. In turn, testing of the sample at RH 65%–85% resulted in swelling of the sample, followed by its shrinking and irreversible changes in its resistance (Figure 6, hollow rhombs and crosses).…”

Section: Resultsmentioning

confidence: 99%

“…EIS measurements were performed using the custom system reported elsewhere, [ 20 ] which allowed regulating the nitrogen gas RH from 5% to 90%, with a gas flow up to 1.0 L min −1 . The relative error in measuring humidity was ±2%.…”

Section: Methodsmentioning

confidence: 99%

Highly Efficient Flexible n‐Type Thermoelectric Films Formed by Encapsulation of Bi₂Se₃‐MWCNT Hybrid Networks in Polyvinyl Alcohol

Buks

Andzane

Bugovecka

et al. 2022

Adv Materials Inter

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where S is the Seebeck coefficient, σ is the electrical conductivity, T is the absolute temperature, and κ is the thermal conductivity. Having both n-and p-type TE materials is an essential requirement for building an efficient TE device. [3] So far the use of organic-inorganic nanocomposites, where electrically conductive p-or n-type polymer is used as a matrix for supporting a network of carbon nanotubes (CNTs) and/or inorganic TE nanostructures as flakes, nanoplates, or nanowires has shown the greatest potential for engineering efficient flexible TE devices. [4] CNTs have been reported to be one of the most promising components for producing p-type flexible TE nanocomposites. [5][6][7][8][9] However, application of CNTs in n-type TE composites is complicated due to necessity of CNTs pretreatment (annealing under high vacuum) for oxygen desorption and transition of their conductivity type from p-type (arising from extrinsically induced by the adsorbed oxygen hole-like concentration [10] ) to n-type, and further isolation from ambient environment (air) to prevent oxygen adsorption. This significantly complicates the practical use of n-type CNTs in ambient conditions (air). Another drawback of n-type conductive polymers and their based composites is poor stability in air, resulting in decrease of electrical conductivity by orders of magnitude when exposed to air even for a short period of time. [10] The use of organic-inorganic nanocomposites has shown the greatest potential for engineering efficient flexible thermoelectric devices. In this work, a novel approach of encapsulation of as-grown bismuth selenide-multiwalled carbon nanotubes (Bi 2 Se 3 -MWCNT) hybrid network in polyvinyl alcohol for fabrication of n-type flexible thermoelectric films is demonstrated as a successful alternative to the mechanically mixed counterparts. The developed stable flexible n-type thermoelectric material has a Seebeck coefficient and power factor at room temperature as high as −85 μV K −1 and 0.4 μW m −1 K −2 , and figure-of-merit, exceeding the value shown by the mixed counterpart by ≈2 orders of magnitude, while requiring 3-4 times less inorganic material in comparison with mixed composites. Charge carrier transport mechanisms and contribution of Bi 2 Se 3 and MWCNT components of not encapsulated and encapsulated hybrid networks to the total Seebeck coefficient, electrical conductance, and power factor are studied. In addition, the fabricated flexible thermoelectric films show good environmental stability at relative humidity levels up to 60%, as well as great mechanical and electrical stability with the increase of resistance within 0.5% and deviations of the Seebeck coefficient within 2% from the initial value during the 100 repetitive bending cycles.

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“…The oxidation of the surface of Bi 2 Se 2.975 Te 0.025 most likely is related to the sample handling and storage in the air. [ 25 ] Presumably, the presence of the ≈1–2 nm thin native oxide on the surface of ultrathin films has no negative effect on their TE properties due to the TE properties of these oxides, comparable with the TE properties the not‐oxidized materials. [ 26,27 ] Based on the XPS measurements, the chemical composition of the Te‐doped Bi 2 Se 3 ultrathin film was determined to be Bi (38 ± 4):Se (≈62 ± 4):Te (≈0.6 ± 0.2), which supports the energy‐dispersive X‐ray diffraction measurements.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Properties of Bismuth Selenide Based Nanolaminates for Application in Thermoelectrics

Andzane

Felsharuk

Buks

et al. 2022

Adv Materials Inter

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In this work, simple and cost‐effective phyiscal vapor deposition method is applied for deposition of single Bi2Se3, Bi1.925Sn0.075Se3, Bi2Se2.975Te0.025 ultrathin films of average thickness 10–12 nm, and for the fabrication of n‐type 5‐layer nanolaminates. The nanolaminates are composed from alternating doped and undoped ultrathin films. Electrical and thermoelectric properties (Seebeck coefficient, resistivity, electron thermal conductivity, charge carrier concentration, and mobility) of nanolaminates as well as single ultrathin undoped and doped films are studied at room temperature under ambient conditions. Both types of nanolaminates show 75–125% increase of the Seebeck coefficient accompanied by the 65–85% reduction of the electron thermal conductivity in comparison with the nanostructured bulk materials of similar chemical compositions. The mechanisms underlying such improvement of properties of studied nanolaminates in comparison with the nanostructured bulk counterparts are discussed.

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EIS characterization of aging and humidity-related behavior of Bi2Se3 films of different morphologies

Cited by 8 publications

References 31 publications

Thermoelectric Properties of Bare and Nonconductive Polymer-Encapsulated Sb₂Te₃-MWCNT Hybrid Networks and Their Application in Flexible Heat-to-Power Conversion Devices

Thermoelectric Properties of Bare and Nonconductive Polymer-Encapsulated Sb₂Te₃-MWCNT Hybrid Networks and Their Application in Flexible Heat-to-Power Conversion Devices

Highly Efficient Flexible n‐Type Thermoelectric Films Formed by Encapsulation of Bi₂Se₃‐MWCNT Hybrid Networks in Polyvinyl Alcohol

Synthesis and Properties of Bismuth Selenide Based Nanolaminates for Application in Thermoelectrics

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EIS characterization of aging and humidity-related behavior of Bi2Se3 films of different morphologies

Cited by 8 publications

References 31 publications

Thermoelectric Properties of Bare and Nonconductive Polymer-Encapsulated Sb2Te3-MWCNT Hybrid Networks and Their Application in Flexible Heat-to-Power Conversion Devices

Thermoelectric Properties of Bare and Nonconductive Polymer-Encapsulated Sb2Te3-MWCNT Hybrid Networks and Their Application in Flexible Heat-to-Power Conversion Devices

Highly Efficient Flexible n‐Type Thermoelectric Films Formed by Encapsulation of Bi2Se3‐MWCNT Hybrid Networks in Polyvinyl Alcohol

Synthesis and Properties of Bismuth Selenide Based Nanolaminates for Application in Thermoelectrics

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Thermoelectric Properties of Bare and Nonconductive Polymer-Encapsulated Sb₂Te₃-MWCNT Hybrid Networks and Their Application in Flexible Heat-to-Power Conversion Devices

Thermoelectric Properties of Bare and Nonconductive Polymer-Encapsulated Sb₂Te₃-MWCNT Hybrid Networks and Their Application in Flexible Heat-to-Power Conversion Devices

Highly Efficient Flexible n‐Type Thermoelectric Films Formed by Encapsulation of Bi₂Se₃‐MWCNT Hybrid Networks in Polyvinyl Alcohol