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Can plasmonic Al nanoparticles improve absorption in triple junction solar cells?

Yang L, Pillai S, Green MA - Sci Rep (2015)

Bottom Line: The particle period, diameter and the thickness of the oxide layers were optimised for the sub-cells using simulations to achieve the lowest reflection and maximum external quantum efficiencies.Our results highlight the importance of proper reference comparison, and unlike previously published results, raise doubts regarding the effectiveness of Al plasmonic nanoparticles as a suitable front-side scattering medium for broadband efficiency enhancements when compared to standard single-layer antireflection coatings.However, by embedding the nanoparticles within the dielectric layer, they have the potential to perform better than an antireflection layer and provide enhanced response from both the sub-cells.

View Article: PubMed Central - PubMed

Affiliation: 1] Australian Centre for Advanced Photovoltaics, University of New South Wales, Sydney, NSW-2052, Australia [2] College of Applied Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu 610059, China.

ABSTRACT
Plasmonic nanoparticles located on the illuminated surface of a solar cell can perform the function of an antireflection layer, as well as a scattering layer, facilitating light-trapping. Al nanoparticles have recently been proposed to aid photocurrent enhancements in GaAs photodiodes in the wavelength region of 400-900 nm by mitigating any parasitic absorption losses. Because this spectral region corresponds to the top and middle sub-cell of a typical GaInP/GaInAs/Ge triple junction solar cell, in this work, we investigated the potential of similar periodic Al nanoparticles placed on top of a thin SiO2 spacer layer that can also serve as an antireflection coating at larger thicknesses. The particle period, diameter and the thickness of the oxide layers were optimised for the sub-cells using simulations to achieve the lowest reflection and maximum external quantum efficiencies. Our results highlight the importance of proper reference comparison, and unlike previously published results, raise doubts regarding the effectiveness of Al plasmonic nanoparticles as a suitable front-side scattering medium for broadband efficiency enhancements when compared to standard single-layer antireflection coatings. However, by embedding the nanoparticles within the dielectric layer, they have the potential to perform better than an antireflection layer and provide enhanced response from both the sub-cells.

No MeSH data available.


Reproduced calculations for a GaAs cell for the photodiode structure reported in Ref 11 for a 100 nm diameter and 50 nm height Al nanoparticle array for different pitch as indicated: (a) Absorption in NPs (inset: device structure), (b) surface reflection, (c) calculated EQE and (d) calculated EQE for a thicker SiO2 layer.
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f1: Reproduced calculations for a GaAs cell for the photodiode structure reported in Ref 11 for a 100 nm diameter and 50 nm height Al nanoparticle array for different pitch as indicated: (a) Absorption in NPs (inset: device structure), (b) surface reflection, (c) calculated EQE and (d) calculated EQE for a thicker SiO2 layer.

Mentions: As a check, we first replicate the calculation for single-junction GaAs photodiodes as reported by others11 and find our results comparable with those published. The GaAs cell comprises a 25-nm SiO2 spacer layer, a 30-nm InGaP window layer, a 500-nm InGaP back surface field layer and a 500-nm active GaAs region on a GaAs substrate (see Fig. 1a inset). The nanoparticle diameter, height and period are 100, 50 and 200 nm, respectively with an additional period of 400 nm for the Al NP. As shown in Fig. 1, the NP absorption spectra (Fig. 1(a)) and the device reflection spectra (Fig. 1(b)) in our calculations are very similar to those reported by other workers11 at most wavelengths. Because 100% IQE is considered in these calculations, the simulated results represent the upper limit EQE of the device. This explains why our calculated EQE in Fig. 1(c) yielded similar trends but with larger values than those from the literature because these were experimental EQE results. In Fig. 1(d), the reference cell and the cell with Al NPs for the 25-nm SiO2 thickness from the original study are compared to the case of the 100 nm-thick SiO2 AR coating with and without the Al NPs and will be discussed more in the later section. The reference cell reported in the literature11 is a cell without NPs but with the same thickness of the SiO2 layer (25 nm) as with the NPs.


Can plasmonic Al nanoparticles improve absorption in triple junction solar cells?

Yang L, Pillai S, Green MA - Sci Rep (2015)

Reproduced calculations for a GaAs cell for the photodiode structure reported in Ref 11 for a 100 nm diameter and 50 nm height Al nanoparticle array for different pitch as indicated: (a) Absorption in NPs (inset: device structure), (b) surface reflection, (c) calculated EQE and (d) calculated EQE for a thicker SiO2 layer.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4490398&req=5

f1: Reproduced calculations for a GaAs cell for the photodiode structure reported in Ref 11 for a 100 nm diameter and 50 nm height Al nanoparticle array for different pitch as indicated: (a) Absorption in NPs (inset: device structure), (b) surface reflection, (c) calculated EQE and (d) calculated EQE for a thicker SiO2 layer.
Mentions: As a check, we first replicate the calculation for single-junction GaAs photodiodes as reported by others11 and find our results comparable with those published. The GaAs cell comprises a 25-nm SiO2 spacer layer, a 30-nm InGaP window layer, a 500-nm InGaP back surface field layer and a 500-nm active GaAs region on a GaAs substrate (see Fig. 1a inset). The nanoparticle diameter, height and period are 100, 50 and 200 nm, respectively with an additional period of 400 nm for the Al NP. As shown in Fig. 1, the NP absorption spectra (Fig. 1(a)) and the device reflection spectra (Fig. 1(b)) in our calculations are very similar to those reported by other workers11 at most wavelengths. Because 100% IQE is considered in these calculations, the simulated results represent the upper limit EQE of the device. This explains why our calculated EQE in Fig. 1(c) yielded similar trends but with larger values than those from the literature because these were experimental EQE results. In Fig. 1(d), the reference cell and the cell with Al NPs for the 25-nm SiO2 thickness from the original study are compared to the case of the 100 nm-thick SiO2 AR coating with and without the Al NPs and will be discussed more in the later section. The reference cell reported in the literature11 is a cell without NPs but with the same thickness of the SiO2 layer (25 nm) as with the NPs.

Bottom Line: The particle period, diameter and the thickness of the oxide layers were optimised for the sub-cells using simulations to achieve the lowest reflection and maximum external quantum efficiencies.Our results highlight the importance of proper reference comparison, and unlike previously published results, raise doubts regarding the effectiveness of Al plasmonic nanoparticles as a suitable front-side scattering medium for broadband efficiency enhancements when compared to standard single-layer antireflection coatings.However, by embedding the nanoparticles within the dielectric layer, they have the potential to perform better than an antireflection layer and provide enhanced response from both the sub-cells.

View Article: PubMed Central - PubMed

Affiliation: 1] Australian Centre for Advanced Photovoltaics, University of New South Wales, Sydney, NSW-2052, Australia [2] College of Applied Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu 610059, China.

ABSTRACT
Plasmonic nanoparticles located on the illuminated surface of a solar cell can perform the function of an antireflection layer, as well as a scattering layer, facilitating light-trapping. Al nanoparticles have recently been proposed to aid photocurrent enhancements in GaAs photodiodes in the wavelength region of 400-900 nm by mitigating any parasitic absorption losses. Because this spectral region corresponds to the top and middle sub-cell of a typical GaInP/GaInAs/Ge triple junction solar cell, in this work, we investigated the potential of similar periodic Al nanoparticles placed on top of a thin SiO2 spacer layer that can also serve as an antireflection coating at larger thicknesses. The particle period, diameter and the thickness of the oxide layers were optimised for the sub-cells using simulations to achieve the lowest reflection and maximum external quantum efficiencies. Our results highlight the importance of proper reference comparison, and unlike previously published results, raise doubts regarding the effectiveness of Al plasmonic nanoparticles as a suitable front-side scattering medium for broadband efficiency enhancements when compared to standard single-layer antireflection coatings. However, by embedding the nanoparticles within the dielectric layer, they have the potential to perform better than an antireflection layer and provide enhanced response from both the sub-cells.

No MeSH data available.