Limits...
Wafer-Scale Integration of Inverted Nanopyramid Arrays for Advanced Light Trapping in Crystalline Silicon Thin Film Solar Cells.

Zhou S, Yang Z, Gao P, Li X, Yang X, Wang D, He J, Ying Z, Ye J - Nanoscale Res Lett (2016)

Bottom Line: Here, we report an efficient light-trapping strategy in c-Si TFs (~20 μm in thickness) that utilizes two-dimensional (2D) arrays of inverted nanopyramid (INP) as surface texturing.Three types of INP arrays with typical periodicities of 300, 670, and 1400 nm, either on front, rear, or both surfaces of the c-Si TFs, are fabricated by scalable colloidal lithography and anisotropic wet etch technique.With the extra aid of antireflection coating, the sufficient optical absorption of 20-μm-thick c-Si with a double-sided 1400-nm INP arrays yields a photocurrent density of 39.86 mA/cm(2), which is about 76 % higher than the flat counterpart (22.63 mA/cm(2)) and is only 3 % lower than the value of Lambertian limit (41.10 mA/cm(2)).

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory for Microstructures, Institute of Materials, Shanghai University, Shanghai, 200072, China.

ABSTRACT
Crystalline silicon thin film (c-Si TF) solar cells with an active layer thickness of a few micrometers may provide a viable pathway for further sustainable development of photovoltaic technology, because of its potentials in cost reduction and high efficiency. However, the performance of such cells is largely constrained by the deteriorated light absorption of the ultrathin photoactive material. Here, we report an efficient light-trapping strategy in c-Si TFs (~20 μm in thickness) that utilizes two-dimensional (2D) arrays of inverted nanopyramid (INP) as surface texturing. Three types of INP arrays with typical periodicities of 300, 670, and 1400 nm, either on front, rear, or both surfaces of the c-Si TFs, are fabricated by scalable colloidal lithography and anisotropic wet etch technique. With the extra aid of antireflection coating, the sufficient optical absorption of 20-μm-thick c-Si with a double-sided 1400-nm INP arrays yields a photocurrent density of 39.86 mA/cm(2), which is about 76 % higher than the flat counterpart (22.63 mA/cm(2)) and is only 3 % lower than the value of Lambertian limit (41.10 mA/cm(2)). The novel surface texturing scheme with 2D INP arrays has the advantages of excellent antireflection and light-trapping capabilities, an inherent low parasitic surface area, a negligible surface damage, and a good compatibility for subsequent process steps, making it a good alternative for high-performance c-Si TF solar cells.

No MeSH data available.


Related in: MedlinePlus

Experimental (a) and simulated (b) reflection spectra of 20-μm-thick c-Si thin films textured by INP arrays with different periodicities on the rear side. The inset in a shows a unit for the periodic array of c-Si and rear-sided INP (coated by a conformal silver film)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4829563&req=5

Fig3: Experimental (a) and simulated (b) reflection spectra of 20-μm-thick c-Si thin films textured by INP arrays with different periodicities on the rear side. The inset in a shows a unit for the periodic array of c-Si and rear-sided INP (coated by a conformal silver film)

Mentions: As the c-Si has low absorption coefficient, especially in the near-infrared region, c-Si TF cells rely crucially on advanced light management scheme to achieve high conversion efficiencies. Therefore, another set of INP arrays is applied onto the rear side of c-Si TF to enhance the diffractions for the light with λ > 800 nm. Similarly, three periodicities of P = 300, 670, and 1400 nm were formed on the rear side [see the inset of Fig. 3a with a silver nanostructured reflector]. The corresponding absorption spectra of experiment and simulation are plotted in Fig. 3a, b, respectively. As predicted, the light reflection for the band of λ < 800 nm exhibits unnoticeable change with the presence of rear INP design, as light in this band has been efficiently absorbed by the photoactive layer before reaching the bottom facet. However, for wavelengths ranging from 800 to 1100 nm, distinct absorption enhancements over the planar counterpart are observed, especially for the design with P = 1400 nm. It is expected that light scattering is improved since the pyramidal shape represents a gradual change from the uniform Si base to the periodic INP grating at the apex, rather than an abrupt change in planar systems. This allows the normally incident light to be coupled and guided laterally, resulting in an increased effective optical path. The oscillation of the simulated absorption spectra in Fig. 3b further confirmed the strong interference of light throughout the INP arrays.Fig. 3


Wafer-Scale Integration of Inverted Nanopyramid Arrays for Advanced Light Trapping in Crystalline Silicon Thin Film Solar Cells.

Zhou S, Yang Z, Gao P, Li X, Yang X, Wang D, He J, Ying Z, Ye J - Nanoscale Res Lett (2016)

Experimental (a) and simulated (b) reflection spectra of 20-μm-thick c-Si thin films textured by INP arrays with different periodicities on the rear side. The inset in a shows a unit for the periodic array of c-Si and rear-sided INP (coated by a conformal silver film)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4829563&req=5

Fig3: Experimental (a) and simulated (b) reflection spectra of 20-μm-thick c-Si thin films textured by INP arrays with different periodicities on the rear side. The inset in a shows a unit for the periodic array of c-Si and rear-sided INP (coated by a conformal silver film)
Mentions: As the c-Si has low absorption coefficient, especially in the near-infrared region, c-Si TF cells rely crucially on advanced light management scheme to achieve high conversion efficiencies. Therefore, another set of INP arrays is applied onto the rear side of c-Si TF to enhance the diffractions for the light with λ > 800 nm. Similarly, three periodicities of P = 300, 670, and 1400 nm were formed on the rear side [see the inset of Fig. 3a with a silver nanostructured reflector]. The corresponding absorption spectra of experiment and simulation are plotted in Fig. 3a, b, respectively. As predicted, the light reflection for the band of λ < 800 nm exhibits unnoticeable change with the presence of rear INP design, as light in this band has been efficiently absorbed by the photoactive layer before reaching the bottom facet. However, for wavelengths ranging from 800 to 1100 nm, distinct absorption enhancements over the planar counterpart are observed, especially for the design with P = 1400 nm. It is expected that light scattering is improved since the pyramidal shape represents a gradual change from the uniform Si base to the periodic INP grating at the apex, rather than an abrupt change in planar systems. This allows the normally incident light to be coupled and guided laterally, resulting in an increased effective optical path. The oscillation of the simulated absorption spectra in Fig. 3b further confirmed the strong interference of light throughout the INP arrays.Fig. 3

Bottom Line: Here, we report an efficient light-trapping strategy in c-Si TFs (~20 μm in thickness) that utilizes two-dimensional (2D) arrays of inverted nanopyramid (INP) as surface texturing.Three types of INP arrays with typical periodicities of 300, 670, and 1400 nm, either on front, rear, or both surfaces of the c-Si TFs, are fabricated by scalable colloidal lithography and anisotropic wet etch technique.With the extra aid of antireflection coating, the sufficient optical absorption of 20-μm-thick c-Si with a double-sided 1400-nm INP arrays yields a photocurrent density of 39.86 mA/cm(2), which is about 76 % higher than the flat counterpart (22.63 mA/cm(2)) and is only 3 % lower than the value of Lambertian limit (41.10 mA/cm(2)).

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory for Microstructures, Institute of Materials, Shanghai University, Shanghai, 200072, China.

ABSTRACT
Crystalline silicon thin film (c-Si TF) solar cells with an active layer thickness of a few micrometers may provide a viable pathway for further sustainable development of photovoltaic technology, because of its potentials in cost reduction and high efficiency. However, the performance of such cells is largely constrained by the deteriorated light absorption of the ultrathin photoactive material. Here, we report an efficient light-trapping strategy in c-Si TFs (~20 μm in thickness) that utilizes two-dimensional (2D) arrays of inverted nanopyramid (INP) as surface texturing. Three types of INP arrays with typical periodicities of 300, 670, and 1400 nm, either on front, rear, or both surfaces of the c-Si TFs, are fabricated by scalable colloidal lithography and anisotropic wet etch technique. With the extra aid of antireflection coating, the sufficient optical absorption of 20-μm-thick c-Si with a double-sided 1400-nm INP arrays yields a photocurrent density of 39.86 mA/cm(2), which is about 76 % higher than the flat counterpart (22.63 mA/cm(2)) and is only 3 % lower than the value of Lambertian limit (41.10 mA/cm(2)). The novel surface texturing scheme with 2D INP arrays has the advantages of excellent antireflection and light-trapping capabilities, an inherent low parasitic surface area, a negligible surface damage, and a good compatibility for subsequent process steps, making it a good alternative for high-performance c-Si TF solar cells.

No MeSH data available.


Related in: MedlinePlus