Limits...
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

Measured (a) transmission and (c) transmission enhancement factor at normal incident angle, respectively. (b,d) Are corresponding simulation results.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4940859&req=5

f2: Measured (a) transmission and (c) transmission enhancement factor at normal incident angle, respectively. (b,d) Are corresponding simulation results.

Mentions: To explore the enhanced transmission based on strong interference dominated by interface phase shift in planar metal/semiconductor double-layered films, Si layers with thicknesses of 10–25 nm (in a 5 nm increment) on 30-nm-thick Ag layers are fabricated and experimental transmission at normal incidence in the visible range (400 nm to 780 nm) is provided in Fig. 2a. The transmission photographs of the fabricated Ag/Si double-layered films on 1 cm × 1 cm glass substrate are displayed in Fig. S1 in the Supplementary Materials. The experimental transmission for Ag/Si double-layered films with other Ag thicknesses (20, 40 and 50 nm) is presented in Fig. S2 in the Supplementary Information. The transmission enhancement factor is defined as the transmission of the Ag/Si double-layered film relative to that of a single Ag film. For a single 30-nm-thick Ag film, the measured transmission drops at increasing wavelength and is below 10% beyond 650 nm wavelength. Once a thin Si layer is covered, a notable resonant enhanced transmission relative to that of the referenced Ag film can be clearly distinguished. The enhanced transmission features a broadband operation. For a 15-nm-thick Si coating, the transmission is enhanced beyond 460 nm wavelength and the measured transmission maximum is 28% at 550 nm, which almost doubles in comparison with that of a single Ag film. By controlling the Si thickness, the strong interference and consequently transmission characteristics of the double-layered film can be manipulated. The transmission peak wavelength red-shifts as the Si thickness is increased. The peak wavelength shifts to around 670 nm when the Si thickness is increased to 25 nm. The transmission enhancement is more significant for a thick Ag film. Specifically, for a 50-nm-thick Ag film at 670 nm, the transmission is increased from 1.3% to 6.3% after coating a 25-nm-thick Si film, exhibiting an over fourth enhancement in the transmission (Figs S2d and S3d). Using the measured optical constants of a-Si and Ag, the calculated transmission and transmission enhancement factor corresponding to the measurements are presented in Fig. 2c,d, respectively. Excellent agreement is obtained between the experimental data and the calculations. The slightly low transmission in experiments can be attributed to the light scattering loss induced by the rough film surfaces.


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)

Measured (a) transmission and (c) transmission enhancement factor at normal incident angle, respectively. (b,d) Are corresponding simulation results.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f2: Measured (a) transmission and (c) transmission enhancement factor at normal incident angle, respectively. (b,d) Are corresponding simulation results.
Mentions: To explore the enhanced transmission based on strong interference dominated by interface phase shift in planar metal/semiconductor double-layered films, Si layers with thicknesses of 10–25 nm (in a 5 nm increment) on 30-nm-thick Ag layers are fabricated and experimental transmission at normal incidence in the visible range (400 nm to 780 nm) is provided in Fig. 2a. The transmission photographs of the fabricated Ag/Si double-layered films on 1 cm × 1 cm glass substrate are displayed in Fig. S1 in the Supplementary Materials. The experimental transmission for Ag/Si double-layered films with other Ag thicknesses (20, 40 and 50 nm) is presented in Fig. S2 in the Supplementary Information. The transmission enhancement factor is defined as the transmission of the Ag/Si double-layered film relative to that of a single Ag film. For a single 30-nm-thick Ag film, the measured transmission drops at increasing wavelength and is below 10% beyond 650 nm wavelength. Once a thin Si layer is covered, a notable resonant enhanced transmission relative to that of the referenced Ag film can be clearly distinguished. The enhanced transmission features a broadband operation. For a 15-nm-thick Si coating, the transmission is enhanced beyond 460 nm wavelength and the measured transmission maximum is 28% at 550 nm, which almost doubles in comparison with that of a single Ag film. By controlling the Si thickness, the strong interference and consequently transmission characteristics of the double-layered film can be manipulated. The transmission peak wavelength red-shifts as the Si thickness is increased. The peak wavelength shifts to around 670 nm when the Si thickness is increased to 25 nm. The transmission enhancement is more significant for a thick Ag film. Specifically, for a 50-nm-thick Ag film at 670 nm, the transmission is increased from 1.3% to 6.3% after coating a 25-nm-thick Si film, exhibiting an over fourth enhancement in the transmission (Figs S2d and S3d). Using the measured optical constants of a-Si and Ag, the calculated transmission and transmission enhancement factor corresponding to the measurements are presented in Fig. 2c,d, respectively. Excellent agreement is obtained between the experimental data and the calculations. The slightly low transmission in experiments can be attributed to the light scattering loss induced by the rough film surfaces.

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