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Transmission enhancement based on strong interference in metal-semiconductor layered film for energy harvesting.

Li Q, Du K, Mao K, Fang X, Zhao D, Ye H, Qiu M - Sci Rep (2016)

Bottom Line: In a metallic film coated with a thin semiconductor film, both transmission and absorption are simultaneously enhanced as a result of dramatically reduced reflection.These planar layered films for transmission enhancement feature ultrathin thickness, broadband and wide-angle operation, and reduced resistance.This strategy relies on no patterned nanostructures and thereby may power up a wide spectrum of energy-harvesting applications such as thin-film photovoltaics and surface photocatalysis.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou 310027, China.

ABSTRACT
A fundamental strategy to enhance optical transmission through a continuous metallic film based on strong interference dominated by interface phase shift is developed. In a metallic film coated with a thin semiconductor film, both transmission and absorption are simultaneously enhanced as a result of dramatically reduced reflection. For a 50-nm-thick Ag film, experimental transmission enhancement factors of 4.5 and 9.5 are realized by exploiting Ag/Si non-symmetric and Si/Ag/Si symmetric geometries, respectively. These planar layered films for transmission enhancement feature ultrathin thickness, broadband and wide-angle operation, and reduced resistance. Considering one of their potential applications as transparent metal electrodes in solar cells, a calculated 182% enhancement in the total transmission efficiency relative to a single metallic film is expected. This strategy relies on no patterned nanostructures and thereby may power up a wide spectrum of energy-harvesting applications such as thin-film photovoltaics and surface photocatalysis.

No MeSH data available.


Related in: MedlinePlus

(a) Contour plot of simulated electric field profile across and above the devices for Ag30 at λ = 580 nm and for Ag30/Si15 at λ = 580 nm and 450 nm. (b,c) Are electric field profile and resistive loss profile across Ag30/Si15 devices for four typical wavelength (λ = 400/520/540/580/780 nm).
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f4: (a) Contour plot of simulated electric field profile across and above the devices for Ag30 at λ = 580 nm and for Ag30/Si15 at λ = 580 nm and 450 nm. (b,c) Are electric field profile and resistive loss profile across Ag30/Si15 devices for four typical wavelength (λ = 400/520/540/580/780 nm).

Mentions: To unveil the physics behind the enhanced transmission, Fig. 4a,b provide the contour plots of simulated electric field profile and corresponding electric field value across all layers at several operating wavelength (including simulated peak transmission wavelength 580 nm, peak absorption wavelength 520 nm, non-resonant wavelength 780 nm) for a Ag/Si (30/15 nm) double-layered film, respectively. For a single 30-nm-thick Ag film, strong reflection causes a standing wave. The amplitude difference between valleys and peaks is strongly related to the reflection. For the Ag/Si (30/15 nm) double-layered film, the standing wave with large amplitude differences between valleys and peaks can still be seen at 780 nm non-resonant wavelength. However, at 580 nm peak transmission wavelength, the reflection is significantly reduced and the amplitude differences between valleys and peaks in the standing wave are suppressed. The absorption loss is related to the imaginary part of medium permittivity and electric field amplitude by , where ε0 is vacuum permittivity and ω is operating frequency. The absorption profile across all layers is provided in Fig. 4c, indicating that most of the absorption occurs in the Si layer as opposed to the underlying Ag layer. At 520 nm wavelength where maximum absorption (~75%) and minimum reflection (~1%) occur, over 72% of the incident light is absorbed in the Si layer whereas only 3% of the light is absorbed in the Ag layer, with the remaining 24% of the light transmitted. At 580 nm wavelength where maximum transmission (~30%) occurs, over 53% of the incident light is absorbed in the Si layer whereas only 5% of the light is absorbed in the Ag layer, with the remaining 12% of the light reflected. Therefore, the transmission can be further enhanced by reducing the loss in the a-Si layer.


Transmission enhancement based on strong interference in metal-semiconductor layered film for energy harvesting.

Li Q, Du K, Mao K, Fang X, Zhao D, Ye H, Qiu M - Sci Rep (2016)

(a) Contour plot of simulated electric field profile across and above the devices for Ag30 at λ = 580 nm and for Ag30/Si15 at λ = 580 nm and 450 nm. (b,c) Are electric field profile and resistive loss profile across Ag30/Si15 devices for four typical wavelength (λ = 400/520/540/580/780 nm).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4940859&req=5

f4: (a) Contour plot of simulated electric field profile across and above the devices for Ag30 at λ = 580 nm and for Ag30/Si15 at λ = 580 nm and 450 nm. (b,c) Are electric field profile and resistive loss profile across Ag30/Si15 devices for four typical wavelength (λ = 400/520/540/580/780 nm).
Mentions: To unveil the physics behind the enhanced transmission, Fig. 4a,b provide the contour plots of simulated electric field profile and corresponding electric field value across all layers at several operating wavelength (including simulated peak transmission wavelength 580 nm, peak absorption wavelength 520 nm, non-resonant wavelength 780 nm) for a Ag/Si (30/15 nm) double-layered film, respectively. For a single 30-nm-thick Ag film, strong reflection causes a standing wave. The amplitude difference between valleys and peaks is strongly related to the reflection. For the Ag/Si (30/15 nm) double-layered film, the standing wave with large amplitude differences between valleys and peaks can still be seen at 780 nm non-resonant wavelength. However, at 580 nm peak transmission wavelength, the reflection is significantly reduced and the amplitude differences between valleys and peaks in the standing wave are suppressed. The absorption loss is related to the imaginary part of medium permittivity and electric field amplitude by , where ε0 is vacuum permittivity and ω is operating frequency. The absorption profile across all layers is provided in Fig. 4c, indicating that most of the absorption occurs in the Si layer as opposed to the underlying Ag layer. At 520 nm wavelength where maximum absorption (~75%) and minimum reflection (~1%) occur, over 72% of the incident light is absorbed in the Si layer whereas only 3% of the light is absorbed in the Ag layer, with the remaining 24% of the light transmitted. At 580 nm wavelength where maximum transmission (~30%) occurs, over 53% of the incident light is absorbed in the Si layer whereas only 5% of the light is absorbed in the Ag layer, with the remaining 12% of the light reflected. Therefore, the transmission can be further enhanced by reducing the loss in the a-Si layer.

Bottom Line: In a metallic film coated with a thin semiconductor film, both transmission and absorption are simultaneously enhanced as a result of dramatically reduced reflection.These planar layered films for transmission enhancement feature ultrathin thickness, broadband and wide-angle operation, and reduced resistance.This strategy relies on no patterned nanostructures and thereby may power up a wide spectrum of energy-harvesting applications such as thin-film photovoltaics and surface photocatalysis.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou 310027, China.

ABSTRACT
A fundamental strategy to enhance optical transmission through a continuous metallic film based on strong interference dominated by interface phase shift is developed. In a metallic film coated with a thin semiconductor film, both transmission and absorption are simultaneously enhanced as a result of dramatically reduced reflection. For a 50-nm-thick Ag film, experimental transmission enhancement factors of 4.5 and 9.5 are realized by exploiting Ag/Si non-symmetric and Si/Ag/Si symmetric geometries, respectively. These planar layered films for transmission enhancement feature ultrathin thickness, broadband and wide-angle operation, and reduced resistance. Considering one of their potential applications as transparent metal electrodes in solar cells, a calculated 182% enhancement in the total transmission efficiency relative to a single metallic film is expected. This strategy relies on no patterned nanostructures and thereby may power up a wide spectrum of energy-harvesting applications such as thin-film photovoltaics and surface photocatalysis.

No MeSH data available.


Related in: MedlinePlus