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Facile microwave-assisted synthesis of Klockmannite CuSe nanosheets and their exceptional electrical properties.

Liu YQ, Wang FX, Xiao Y, Peng HD, Zhong HJ, Liu ZH, Pan GB - Sci Rep (2014)

Bottom Line: This is ascribed to the quantum size effect of NS and the presence of Schottky barrier.In addition, the influence of the molar ratio of Cu(2+)/SeO2, reaction temperature, and reaction time on the growth of CuSe NSs is explored.The template effect of oleylamine and the intrinsic crystal nature of CuSe NS are proposed to account for the growth of hexagonal CuSe NSs.

View Article: PubMed Central - PubMed

Affiliation: Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, 215123 Suzhou, P. R. China.

ABSTRACT
Klockmannite copper selenide nanosheets (CuSe NSs) are synthesized by a facile microwave-assisted method and fully characterized. The nanosheets have smooth surface and hexagonal shape. The lateral size is 200-500 nm × 400-800 nm and the thickness is 55 ± 20 nm. The current-voltage characteristics of CuSe NS films show unique Ohmic and high-conducting behaviors, comparable to the thermally-deposited gold electrode. The high electrical conductivity of CuSe NSs implies their promising applications in printed electronics and nanodevices. Moreover, the local electrical variation is observed, for the first time, within an individual CuSe NS at low bias voltages (0.1 ~ 3 V) by conductive atomic force microscopy (C-AFM). This is ascribed to the quantum size effect of NS and the presence of Schottky barrier. In addition, the influence of the molar ratio of Cu(2+)/SeO2, reaction temperature, and reaction time on the growth of CuSe NSs is explored. The template effect of oleylamine and the intrinsic crystal nature of CuSe NS are proposed to account for the growth of hexagonal CuSe NSs.

No MeSH data available.


(a) Typical diffuse reflectance spectra for CuSe nanosheets. (b) Plots of [F(R)hν]1/2 and [F(R)hν]2 vs energy for the CuSe nanosheets, from which indirect and direct band-gap energies are obtained.
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f3: (a) Typical diffuse reflectance spectra for CuSe nanosheets. (b) Plots of [F(R)hν]1/2 and [F(R)hν]2 vs energy for the CuSe nanosheets, from which indirect and direct band-gap energies are obtained.

Mentions: The optical band gap of CuSe NSs, a crucial electronic parameter for semiconductor nanomaterials, is explored by diffuse reflectance spectroscopy. Typical spectrum (Fig. 3a) shows that the onset of absorption for CuSe NSs is near 1400 nm. By applying Kubelka-Munk transformation2728, a plot of [F(R)hν]1/2 versus energy yields an indirect band gap of 0.94 eV, while a plot of [F(R)hν]2 versus energy yields a direct band gap of 1.36 eV (Fig. 3b). By using the direct band-gap method, the band edge is blue-shifted by ~0.31 eV in relation to bulk CuSe (1.05 eV)829. The band structure of CuSe NSs is also studied by cyclic voltammetry (CV, Fig. S3)30. The onset potential of the reduction of pyridine-treated CuSe NSs appears at −0.2 V vs. Ag/Ag+. Therefore, the bottom of the conduction band (the lowest unoccupied molecular orbital, LUMO) can be determined as −4.51 eV from vacuum level. Moreover, in view of the direct optical band gap of CuSe NSs (1.36 eV), the top of the valence band (the highest occupied molecular orbital, HOMO) can be determined as −5.87 eV.


Facile microwave-assisted synthesis of Klockmannite CuSe nanosheets and their exceptional electrical properties.

Liu YQ, Wang FX, Xiao Y, Peng HD, Zhong HJ, Liu ZH, Pan GB - Sci Rep (2014)

(a) Typical diffuse reflectance spectra for CuSe nanosheets. (b) Plots of [F(R)hν]1/2 and [F(R)hν]2 vs energy for the CuSe nanosheets, from which indirect and direct band-gap energies are obtained.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4126004&req=5

f3: (a) Typical diffuse reflectance spectra for CuSe nanosheets. (b) Plots of [F(R)hν]1/2 and [F(R)hν]2 vs energy for the CuSe nanosheets, from which indirect and direct band-gap energies are obtained.
Mentions: The optical band gap of CuSe NSs, a crucial electronic parameter for semiconductor nanomaterials, is explored by diffuse reflectance spectroscopy. Typical spectrum (Fig. 3a) shows that the onset of absorption for CuSe NSs is near 1400 nm. By applying Kubelka-Munk transformation2728, a plot of [F(R)hν]1/2 versus energy yields an indirect band gap of 0.94 eV, while a plot of [F(R)hν]2 versus energy yields a direct band gap of 1.36 eV (Fig. 3b). By using the direct band-gap method, the band edge is blue-shifted by ~0.31 eV in relation to bulk CuSe (1.05 eV)829. The band structure of CuSe NSs is also studied by cyclic voltammetry (CV, Fig. S3)30. The onset potential of the reduction of pyridine-treated CuSe NSs appears at −0.2 V vs. Ag/Ag+. Therefore, the bottom of the conduction band (the lowest unoccupied molecular orbital, LUMO) can be determined as −4.51 eV from vacuum level. Moreover, in view of the direct optical band gap of CuSe NSs (1.36 eV), the top of the valence band (the highest occupied molecular orbital, HOMO) can be determined as −5.87 eV.

Bottom Line: This is ascribed to the quantum size effect of NS and the presence of Schottky barrier.In addition, the influence of the molar ratio of Cu(2+)/SeO2, reaction temperature, and reaction time on the growth of CuSe NSs is explored.The template effect of oleylamine and the intrinsic crystal nature of CuSe NS are proposed to account for the growth of hexagonal CuSe NSs.

View Article: PubMed Central - PubMed

Affiliation: Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, 215123 Suzhou, P. R. China.

ABSTRACT
Klockmannite copper selenide nanosheets (CuSe NSs) are synthesized by a facile microwave-assisted method and fully characterized. The nanosheets have smooth surface and hexagonal shape. The lateral size is 200-500 nm × 400-800 nm and the thickness is 55 ± 20 nm. The current-voltage characteristics of CuSe NS films show unique Ohmic and high-conducting behaviors, comparable to the thermally-deposited gold electrode. The high electrical conductivity of CuSe NSs implies their promising applications in printed electronics and nanodevices. Moreover, the local electrical variation is observed, for the first time, within an individual CuSe NS at low bias voltages (0.1 ~ 3 V) by conductive atomic force microscopy (C-AFM). This is ascribed to the quantum size effect of NS and the presence of Schottky barrier. In addition, the influence of the molar ratio of Cu(2+)/SeO2, reaction temperature, and reaction time on the growth of CuSe NSs is explored. The template effect of oleylamine and the intrinsic crystal nature of CuSe NS are proposed to account for the growth of hexagonal CuSe NSs.

No MeSH data available.