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Light Trapping Enhancement in a Thin Film with 2D Conformal Periodic Hexagonal Arrays.

Yang X, Zhou S, Wang D, He J, Zhou J, Li X, Gao P, Ye J - Nanoscale Res Lett (2015)

Bottom Line: Compared with the planar reference, the double-sided conformal periodic structures with all feature periodicities of sub-wavelength (300 nm), mid-wavelength (640 nm), and infrared wavelength (2300 nm) show significant broadband absorption enhancements under wide angles.The films with an optimum periodicity of 300 nm exhibit outstanding antireflection and excellent trade-off between light scattering performance and parasitic absorption loss.The average absorption of the optimum structure with a thickness of 160 nm is 64.8 %, which is much larger than the planar counterpart of 38.5 %.

View Article: PubMed Central - PubMed

Affiliation: Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China, yangx@nimte.ac.cn.

ABSTRACT
Applying a periodic light trapping array is an effective method to improve the optical properties in thin-film solar cells. In this work, we experimentally and theoretically investigate the light trapping properties of two-dimensional periodic hexagonal arrays in the framework of a conformal amorphous silicon film. Compared with the planar reference, the double-sided conformal periodic structures with all feature periodicities of sub-wavelength (300 nm), mid-wavelength (640 nm), and infrared wavelength (2300 nm) show significant broadband absorption enhancements under wide angles. The films with an optimum periodicity of 300 nm exhibit outstanding antireflection and excellent trade-off between light scattering performance and parasitic absorption loss. The average absorption of the optimum structure with a thickness of 160 nm is 64.8 %, which is much larger than the planar counterpart of 38.5 %. The methodology applied in this work can be generalized to rational design of other types of high-performance thin-film photovoltaic devices based on a broad range of materials.

No MeSH data available.


Related in: MedlinePlus

Dependence of absorption on the periodicity and incident angle. a Calculated absorption of a-Si under normal incident light versus varied periodicity and wavelength. The thickness of a-Si is fixed at 160 nm. b Calculated absorption of a-Si versus varied incident angle and wavelength. The thickness of a-Si is 160 nm, and the periodicity is 300 nm
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Fig9: Dependence of absorption on the periodicity and incident angle. a Calculated absorption of a-Si under normal incident light versus varied periodicity and wavelength. The thickness of a-Si is fixed at 160 nm. b Calculated absorption of a-Si versus varied incident angle and wavelength. The thickness of a-Si is 160 nm, and the periodicity is 300 nm

Mentions: Furthermore, we theoretically study the active film on the conformal ordered arrays with periodicity ranging from sub-wavelength to 2× typical wavelengths (100–1000 nm) on the front surface of the 100-nm-thick ZnO layer and optimize it to maximize photoabsorption within a given thickness of 160 nm. As shown in Fig. 9a, with increasing P, the absorption peaks are redshifted, degrading the average absorption due to the low reflection reduction and the parasitic absorption; however, when P < 300 nm, a weak scattering leads to a higher optical loss at a longer wavelength range and hinders the absorption improvement. The structure with P = 300 nm has the highest average absorption after the trade-off between the light scattering and the parasitic absorption [30]. Finally, the angular dependence of the light absorption is also interesting to consider. The properties of diffraction gratings are naturally dependent on the incident angle. The behavior under oblique illumination conditions is an important part of the performance investigation of periodic structures. We consider only a single wavelength of the extended spectrum that reaches the back side, and we neglect the fact that the diffraction efficiencies will also change with the incident angle. The polar angle of the diffracted orders θ0 can be found from Eq. (1) [17].Fig. 9


Light Trapping Enhancement in a Thin Film with 2D Conformal Periodic Hexagonal Arrays.

Yang X, Zhou S, Wang D, He J, Zhou J, Li X, Gao P, Ye J - Nanoscale Res Lett (2015)

Dependence of absorption on the periodicity and incident angle. a Calculated absorption of a-Si under normal incident light versus varied periodicity and wavelength. The thickness of a-Si is fixed at 160 nm. b Calculated absorption of a-Si versus varied incident angle and wavelength. The thickness of a-Si is 160 nm, and the periodicity is 300 nm
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4495099&req=5

Fig9: Dependence of absorption on the periodicity and incident angle. a Calculated absorption of a-Si under normal incident light versus varied periodicity and wavelength. The thickness of a-Si is fixed at 160 nm. b Calculated absorption of a-Si versus varied incident angle and wavelength. The thickness of a-Si is 160 nm, and the periodicity is 300 nm
Mentions: Furthermore, we theoretically study the active film on the conformal ordered arrays with periodicity ranging from sub-wavelength to 2× typical wavelengths (100–1000 nm) on the front surface of the 100-nm-thick ZnO layer and optimize it to maximize photoabsorption within a given thickness of 160 nm. As shown in Fig. 9a, with increasing P, the absorption peaks are redshifted, degrading the average absorption due to the low reflection reduction and the parasitic absorption; however, when P < 300 nm, a weak scattering leads to a higher optical loss at a longer wavelength range and hinders the absorption improvement. The structure with P = 300 nm has the highest average absorption after the trade-off between the light scattering and the parasitic absorption [30]. Finally, the angular dependence of the light absorption is also interesting to consider. The properties of diffraction gratings are naturally dependent on the incident angle. The behavior under oblique illumination conditions is an important part of the performance investigation of periodic structures. We consider only a single wavelength of the extended spectrum that reaches the back side, and we neglect the fact that the diffraction efficiencies will also change with the incident angle. The polar angle of the diffracted orders θ0 can be found from Eq. (1) [17].Fig. 9

Bottom Line: Compared with the planar reference, the double-sided conformal periodic structures with all feature periodicities of sub-wavelength (300 nm), mid-wavelength (640 nm), and infrared wavelength (2300 nm) show significant broadband absorption enhancements under wide angles.The films with an optimum periodicity of 300 nm exhibit outstanding antireflection and excellent trade-off between light scattering performance and parasitic absorption loss.The average absorption of the optimum structure with a thickness of 160 nm is 64.8 %, which is much larger than the planar counterpart of 38.5 %.

View Article: PubMed Central - PubMed

Affiliation: Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China, yangx@nimte.ac.cn.

ABSTRACT
Applying a periodic light trapping array is an effective method to improve the optical properties in thin-film solar cells. In this work, we experimentally and theoretically investigate the light trapping properties of two-dimensional periodic hexagonal arrays in the framework of a conformal amorphous silicon film. Compared with the planar reference, the double-sided conformal periodic structures with all feature periodicities of sub-wavelength (300 nm), mid-wavelength (640 nm), and infrared wavelength (2300 nm) show significant broadband absorption enhancements under wide angles. The films with an optimum periodicity of 300 nm exhibit outstanding antireflection and excellent trade-off between light scattering performance and parasitic absorption loss. The average absorption of the optimum structure with a thickness of 160 nm is 64.8 %, which is much larger than the planar counterpart of 38.5 %. The methodology applied in this work can be generalized to rational design of other types of high-performance thin-film photovoltaic devices based on a broad range of materials.

No MeSH data available.


Related in: MedlinePlus