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Open structure ZnO/CdSe core/shell nanoneedle arrays for solar cells.

Chen Y, Wei L, Zhang G, Jiao J - Nanoscale Res Lett (2012)

Bottom Line: A uniform CdSe shell layer with a grain size of approximately several tens of nanometers was formed on the surface of ZnO nanoneedle cores after annealing at 400°C for 1.5 h.Fabricated solar cells based on these nanostructures exhibited a high short-circuit current density of about 10.5 mA/cm2 and an overall power conversion efficiency of 1.07% with solar illumination of 100 mW/cm2.Incident photo-to-current conversion efficiencies higher than 75% were also obtained.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Physics and State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, People's Republic of China. cyx@sdu.edu.cn.

ABSTRACT
Open structure ZnO/CdSe core/shell nanoneedle arrays were prepared on a conducting glass (SnO2:F) substrate by solution deposition and electrochemical techniques. A uniform CdSe shell layer with a grain size of approximately several tens of nanometers was formed on the surface of ZnO nanoneedle cores after annealing at 400°C for 1.5 h. Fabricated solar cells based on these nanostructures exhibited a high short-circuit current density of about 10.5 mA/cm2 and an overall power conversion efficiency of 1.07% with solar illumination of 100 mW/cm2. Incident photo-to-current conversion efficiencies higher than 75% were also obtained.

No MeSH data available.


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Typical SEM images of ZnO nanoneedle arrays and ZnO/CdSe core/shell nanostructures. (a) SEM image (40° tilted) of a ZnO nanoneedle array grown on SnO2:F substrate by solution method. The average length of the nanoneedle is about 4 to 5 μm. The diameter to the tip is 10 nm, and the diameter to the base is 200 nm. (b) SEM image (40° tilted) of a ZnO/CdSe core/shell nanoneedle array coated by electrodeposition. Inset: HRTEM image of a CdSe grain.
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Figure 1: Typical SEM images of ZnO nanoneedle arrays and ZnO/CdSe core/shell nanostructures. (a) SEM image (40° tilted) of a ZnO nanoneedle array grown on SnO2:F substrate by solution method. The average length of the nanoneedle is about 4 to 5 μm. The diameter to the tip is 10 nm, and the diameter to the base is 200 nm. (b) SEM image (40° tilted) of a ZnO/CdSe core/shell nanoneedle array coated by electrodeposition. Inset: HRTEM image of a CdSe grain.

Mentions: Figure 1a shows an image of an as-grown ZnO nanoneedle array taken by a field emission scanning electron microscope. The SEM image clearly shows that ZnO nanoneedles with sharp tips are grown vertically on the SnO2:F substrate. Further analysis indicates that the average length of the nanoneedles is about 4 to 5 μm, and the diameters are 10 nm at the tip and 200 nm at the base. This nanoneedle array presents an easily accessed open structure for CdSe deposition and higher hole transferring speed for the whole solar cell. No significant changes in nanoneedle array morphology were observed after annealing at 500°C. After the deposition of CdSe layer and annealing, a conformal and uniform coverage of all nanoneedles can be seen in Figure 1b. The oval grains of CdSe form with a diameter of about several tens of nanometers are distributed uniformly over the entire nanoneedle (with no shadowing effects at the base which would otherwise be more prevalent with PVD methods). The single crystallinity of CdSe grains was confirmed by HRTEM study, as displayed in the inset of Figure 1b. The lattice spacing obtained from this HRTEM image was 0.36 nm, which corresponds to the separation between the {100} lattice planes of wurtzite CdSe.


Open structure ZnO/CdSe core/shell nanoneedle arrays for solar cells.

Chen Y, Wei L, Zhang G, Jiao J - Nanoscale Res Lett (2012)

Typical SEM images of ZnO nanoneedle arrays and ZnO/CdSe core/shell nanostructures. (a) SEM image (40° tilted) of a ZnO nanoneedle array grown on SnO2:F substrate by solution method. The average length of the nanoneedle is about 4 to 5 μm. The diameter to the tip is 10 nm, and the diameter to the base is 200 nm. (b) SEM image (40° tilted) of a ZnO/CdSe core/shell nanoneedle array coated by electrodeposition. Inset: HRTEM image of a CdSe grain.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3475031&req=5

Figure 1: Typical SEM images of ZnO nanoneedle arrays and ZnO/CdSe core/shell nanostructures. (a) SEM image (40° tilted) of a ZnO nanoneedle array grown on SnO2:F substrate by solution method. The average length of the nanoneedle is about 4 to 5 μm. The diameter to the tip is 10 nm, and the diameter to the base is 200 nm. (b) SEM image (40° tilted) of a ZnO/CdSe core/shell nanoneedle array coated by electrodeposition. Inset: HRTEM image of a CdSe grain.
Mentions: Figure 1a shows an image of an as-grown ZnO nanoneedle array taken by a field emission scanning electron microscope. The SEM image clearly shows that ZnO nanoneedles with sharp tips are grown vertically on the SnO2:F substrate. Further analysis indicates that the average length of the nanoneedles is about 4 to 5 μm, and the diameters are 10 nm at the tip and 200 nm at the base. This nanoneedle array presents an easily accessed open structure for CdSe deposition and higher hole transferring speed for the whole solar cell. No significant changes in nanoneedle array morphology were observed after annealing at 500°C. After the deposition of CdSe layer and annealing, a conformal and uniform coverage of all nanoneedles can be seen in Figure 1b. The oval grains of CdSe form with a diameter of about several tens of nanometers are distributed uniformly over the entire nanoneedle (with no shadowing effects at the base which would otherwise be more prevalent with PVD methods). The single crystallinity of CdSe grains was confirmed by HRTEM study, as displayed in the inset of Figure 1b. The lattice spacing obtained from this HRTEM image was 0.36 nm, which corresponds to the separation between the {100} lattice planes of wurtzite CdSe.

Bottom Line: A uniform CdSe shell layer with a grain size of approximately several tens of nanometers was formed on the surface of ZnO nanoneedle cores after annealing at 400°C for 1.5 h.Fabricated solar cells based on these nanostructures exhibited a high short-circuit current density of about 10.5 mA/cm2 and an overall power conversion efficiency of 1.07% with solar illumination of 100 mW/cm2.Incident photo-to-current conversion efficiencies higher than 75% were also obtained.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Physics and State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, People's Republic of China. cyx@sdu.edu.cn.

ABSTRACT
Open structure ZnO/CdSe core/shell nanoneedle arrays were prepared on a conducting glass (SnO2:F) substrate by solution deposition and electrochemical techniques. A uniform CdSe shell layer with a grain size of approximately several tens of nanometers was formed on the surface of ZnO nanoneedle cores after annealing at 400°C for 1.5 h. Fabricated solar cells based on these nanostructures exhibited a high short-circuit current density of about 10.5 mA/cm2 and an overall power conversion efficiency of 1.07% with solar illumination of 100 mW/cm2. Incident photo-to-current conversion efficiencies higher than 75% were also obtained.

No MeSH data available.


Related in: MedlinePlus