Highly Enhanced Thermoelectric Properties of Bi/Bi<sub>2</sub>S<sub>3</sub> Nanocomposites

Ge, Zhen‐Hua; Qin, Peng; He, Dongsheng; Chong, Xiaoyu; Feng, Dan; Ji, Yi-Hong; Feng, Jing; He, Jiaqing

doi:10.1021/acsami.6b14803

Cited by 114 publications

(63 citation statements)

References 30 publications

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“…Therefore, the zT s are usually high in tellurides and selenides, but they are low in sulfides. This is the general phenomenon that has been observed in those well‐known TE materials such as Bi 2 X 3 ‐, SnX‐, and PbX‐based compounds (X = S, Se, and Te) . As shown in Figure , the zT values gradually improve as the anion element change from S to Se and then to Te.…”

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confidence: 52%

Are Cu₂Te‐Based Compounds Excellent Thermoelectric Materials?

et al. 2019

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With the increasingly serious environmental pollution and intensified energy crisis, exploitation and utilization of new kinds of clean energy resources are imperative. Among them, thermoelectric (TE) conversion technology based on highperformance TE materials enables direct energy conversion between heat and electricity through the movement of internal phonons and charge carriers. [1][2][3][4] It has shown extensive and important prospects in power generation using industrial waste heat and electronic refrigeration. [5] The energy conversion efficiency of a TE material is mainly determined by its dimensionless figure of merit, defined as zT = σS 2 T/(κ L + κ e ), where σ, S, T, κ L , and κ e are the electrical conductivity, Seebeck coefficient, absolute temperature, lattice thermal conductivity, and electronic thermal conductivity, respectively. The general criteria for high zTs require high crystal symmetry for materials, many valleys (carrier pockets) near the Fermi level, heavy elements with small electronegativity differences between the constituent elements, or complex crystal structure, etc. [6][7][8][9][10] For the constituent elements in the same group such as S, Se, and Te, the heavy one (Te and Se) always has large atomic mass for low κ L and more covalent bonding character for large carrier mobility (µ H ) and thus outstanding electrical transports. [10] Therefore, the zTs are usually high in tellurides and selenides, but they are low in sulfides. This is the general phenomenon that has been observed in those well-known TE materials such as Bi 2 X 3 -, SnX-, and PbX-based compounds (X = S, Se, and Te). As shown in Figure 1, the zT values gradually improve as the anion element change from S to Se and then to Te. However, the case is different in Cu 2 X-based liquidlike TE materials that are among the hottest materials in recent TE study. They possess exceptionally low thermal conductivity and excellent zTs with the values of 1.7-1.9 for Cu 2 S, 1.5-2.3 for Cu 2 Se, and 0.4-1.1 for Cu 2 Te (see Figure 1). [48][49][50][51][52][53][54][55][56][57][58][59][60][61][62] It is quite abnormal and interesting that the zT in Cu 2 Te is lower than those in Cu 2 S and Cu 2 Se. As we known, tellurium is less electronegative, thus the chemical bonds between Cu and Te should be less ionic as compared with those in Cu 2 S and Cu 2 Se, which is beneficial for large µ H and electrical transports. Besides, the κ L in Cu 2 Te is expected lower than or similar to those in Cu 2 S and Cu 2 Se because tellurium is much heavier than sulfur and Most of the state-of-the-art thermoelectric (TE) materials exhibit high crystal symmetry, multiple valleys near the Fermi level, heavy constituent elements with small electronegativity differences, or complex crystal structure. Typically, such general features have been well observed in those well-known TE materials such as Bi 2 X 3 -, SnX-, and PbX-based compounds (X = S, Se, and Te). The performance is usually high in the materials with heavy constituent elements such as Te and Se, bu...

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confidence: 52%

Are Cu₂Te‐Based Compounds Excellent Thermoelectric Materials?

et al. 2019

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“…Recently, Ge et al. reported that the composite of Bi/Bi 2 S 3 holds highly enhanced thermoelectric properties, indicating that increasing Bi‐level in their sulfide parent phase is an effective strategy to achieve high performance samples. Zhang et al.…”

Section: Introductionmentioning

confidence: 99%

Phase‐Controlled Synthesis of High‐Bi‐Ratio Ternary Sulfide Nanocrystals of Cu_1.57Bi_4.57S₈ and Cu_2.93Bi_4.89S₉

et al. 2018

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High Bi‐ratio ternary sulfides have been recently reported as superior thermoelectric materials. However, the synthesis of high Bi‐ratio Cu−Bi−S nanocrystal remains a challenge. Reported here are the synthesis and characterization of three‐phase Cu−Bi−S nanocrystals with the nominal chemical formulae of Cu1.57Bi4.57S8, Cu2.93Bi4.89S9 and Cu3BiS3. The samples were prepared using a Bi2S3 precursor by varying the amount and type of Cu2‐xS (i. e. Cu2S or Cu7.2S4) reactants. TEM images reveal that two new samples crystalized having nanorod morphology with radii of approximately 50 nm and lengths of 200 nm. XPS results indicate that the valence states of Bi in both the two new phases are +3 with viable oxidation states for Cu. UV‐Vis‐NIR absorption spectroscopy reveals that narrow direct bandgaps are 1.12 and 1.27 eV for Cu1.57Bi4.57S8 and Cu2.93Bi4.89S9, respectively. Besides, this method could also be applied to synthesize the Cu3BiS3 phase with a new nanoplate morphology. The as‐synthesized Cu−Bi−S samples show Cu/Bi ratio‐dependent photoresponsive properties. This study not only reports the structure and bandgap of two ternary sulfides, which have only been discovered in the mineral previously, but also provides an efficient method for synthesizing Bi‐rich ternary chalcogenide nanocrystals.

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“…Notwithstanding, the application of bare Bi 2 S 3 is still limited as the recombination process of the photogenerated electron-hole pairs is fast. So many methods were developed to ameliorate the photocatalytic activity of Bi 2 S 3 including morphology control [17], vacancy introduction [18], combination of other semiconductors [19], fabrication of heterojunction [20], incorporation of conductive materials (graphene) [21] or surface plasma resonance [22], etc. Among them, the fabrication of the heterojunction structure was a facile and effective method to improve the photocatalytic properties of the photocatalysts.…”

Section: Introductionmentioning

confidence: 99%

Facile Synthesis of Heterojunctioned ZnO/Bi2S3 Nanocomposites for Enhanced Photocatalytic Reduction of Aqueous Cr(VI) under Visible-Light Irradiation

Yuan

Feng

et al. 2019

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Heterojunctioned ZnO/Bi2S3 nanocomposites were prepared via a facile solvothermal method. The obtained photocatalysts were characterized by X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), High resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), UV-Vis diffuse reflectance spectroscopy (DRS), and Photoelectrochemical and Photoluminescence spectroscopy (PL), respectively. The results showed that ZnO/Bi2S3 composites exhibited the sandwiched-like structure, where ZnO nanoparticles were randomly embedded between Bi2S3 nanoflakes. The performance of photocatalytic Cr(VI) reduction under visible light indicated that ZnO/Bi2S3 composites exhibited high-efficiency photocatalytic activity in comparison with either Bi2S3 or ZnO. The 5%-ZnO/Bi2S3 photocatalyst removed 96% of Cr(VI) within 120 min at 20 mg/L initial concentration of Cr(VI). The enhanced performance of ZnO/Bi2S3 photocatalysts could be ascribed to the increased light harvesting and the effective separation and transfer of the photogenerated charge carriers across the heterojunction interface of the ZnO/Bi2S3 composite. This work could pave the way for the design of new hetero-structured materials and has great potential in environmental remediation.

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Highly Enhanced Thermoelectric Properties of Bi/Bi₂S₃ Nanocomposites

Cited by 114 publications

References 30 publications

Are Cu₂Te‐Based Compounds Excellent Thermoelectric Materials?

Are Cu₂Te‐Based Compounds Excellent Thermoelectric Materials?

Phase‐Controlled Synthesis of High‐Bi‐Ratio Ternary Sulfide Nanocrystals of Cu_1.57Bi_4.57S₈ and Cu_2.93Bi_4.89S₉

Facile Synthesis of Heterojunctioned ZnO/Bi2S3 Nanocomposites for Enhanced Photocatalytic Reduction of Aqueous Cr(VI) under Visible-Light Irradiation

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Highly Enhanced Thermoelectric Properties of Bi/Bi2S3 Nanocomposites

Cited by 114 publications

References 30 publications

Are Cu2Te‐Based Compounds Excellent Thermoelectric Materials?

Are Cu2Te‐Based Compounds Excellent Thermoelectric Materials?

Phase‐Controlled Synthesis of High‐Bi‐Ratio Ternary Sulfide Nanocrystals of Cu1.57Bi4.57S8 and Cu2.93Bi4.89S9

Facile Synthesis of Heterojunctioned ZnO/Bi2S3 Nanocomposites for Enhanced Photocatalytic Reduction of Aqueous Cr(VI) under Visible-Light Irradiation

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Highly Enhanced Thermoelectric Properties of Bi/Bi₂S₃ Nanocomposites

Are Cu₂Te‐Based Compounds Excellent Thermoelectric Materials?

Are Cu₂Te‐Based Compounds Excellent Thermoelectric Materials?

Phase‐Controlled Synthesis of High‐Bi‐Ratio Ternary Sulfide Nanocrystals of Cu_1.57Bi_4.57S₈ and Cu_2.93Bi_4.89S₉