Abstract:The implementation of a front and back grating in ultra-thin photovoltaic cells is a promising approach towards improving light trapping. A simple design rule was developed using the least common multiple (LCM) of the front and back grating periods. From this design rule, several optimal period combinations can be found, providing greater design flexibility for absorbers of indirect band gap materials. Using numerical simulations, the photo-generated current (J ph) for a 10-μm-thick crystalline silicon absorbe… Show more
“…Even moderate improvements of this parameter are of great interest because they may save materials and space in solar power stations relying on this technology. Actually, relative increases in the order of 8-12% have been considered as promising when applied to different types of solar cells incorporating nanostructures and light trapping schemes [5][6][7]. Large increases in efficiency and J sc are reserved for innovative materials and disruptive technologies.…”
Absorption of amorphous-Si hydrogenated (aSi-H) solar cells can be enhanced by using dielectric nanostructures made of Si 3 N 4 that work like antireflection coatings. The analysis focus on the short-circuit current delivered by the cell under solar irradiance, and it is made taking into account every layer and structure of an aSi-H cell. A customized design of the antireflection coating in the form of nanostructured dielectric layers, produces a short-circuit current enhancement of 15.2% with respect to the reference flat solar cell, and a lower reflectivity of the cell. Three different geometries of linear nanostructures have been analyzed and compared with quite similar results among them. An improvement in performance has been also obtained for realizable geometrical dimensions that could be fabricated while maintaining electric conductivity of the front contact.
“…Even moderate improvements of this parameter are of great interest because they may save materials and space in solar power stations relying on this technology. Actually, relative increases in the order of 8-12% have been considered as promising when applied to different types of solar cells incorporating nanostructures and light trapping schemes [5][6][7]. Large increases in efficiency and J sc are reserved for innovative materials and disruptive technologies.…”
Absorption of amorphous-Si hydrogenated (aSi-H) solar cells can be enhanced by using dielectric nanostructures made of Si 3 N 4 that work like antireflection coatings. The analysis focus on the short-circuit current delivered by the cell under solar irradiance, and it is made taking into account every layer and structure of an aSi-H cell. A customized design of the antireflection coating in the form of nanostructured dielectric layers, produces a short-circuit current enhancement of 15.2% with respect to the reference flat solar cell, and a lower reflectivity of the cell. Three different geometries of linear nanostructures have been analyzed and compared with quite similar results among them. An improvement in performance has been also obtained for realizable geometrical dimensions that could be fabricated while maintaining electric conductivity of the front contact.
“…In addition, the rear surface pyramid gratings can increase transmission of the visible and near-infrared light seen from Fig. 3 (c), which is beneficial to be used in near-infrared photodetectors and other fields [ 9 , 10 ]. Fig.…”
Section: Resultsmentioning
confidence: 99%
“…The optimization design of parameters has become more urgent and necessary, especially for the crystalline silicon (CS) thin-film solar cells [ 3 – 6 ]. There are some reports on the double-sided grating design applied to CS thin-film solar cells, and all of them have expressed similar opinions that such a structure can achieve broadband light absorption enhancement which is able to reach the Yablonovitch limit [ 7 – 10 ]. There is no doubt that the double-sided grating design can improve the overall light trapping capability of CS solar cells.…”
The design of double-sided pyramid grating structure can be used to enhance broadband light absorption. The front grating can greatly reduce the light reflection, especially in the short-wavelength region, and the rear grating can also achieve that same effect in the longer wavelength region. In the paper, for the double-sided pyramid grating structure, the photon absorption distribution of each part is studied and compared with the bare crystalline silicon. Theoretical results show that, by reasonably adjusting the structure parameters of the double-sided grating, the light reflection of the whole band can be reduced greatly which is beneficial for black silicon formation and the total light absorption is also increased. However, further studies have shown that using the rear grating does not improve the effective light absorption of the crystalline silicon.
“…In this paper, we propose an experimentally feasible indium‐rich In 0.6 Ga 0.4 N/GaN p‐i‐n thin film–based solar cell with a dual nanograting (NG) structure: an Ag nanograting on the backside of the solar cell and a GaN nanograting on frontside of the solar cell (see Figure ). Some researchers have recently proposed the use of dual nanogratings in silicon (crystalline, microcrystalline, and amorphous) and organic solar cells etc . In most of these solar cells, the nanogratings are in direct contact with the active region of the solar cells.…”
In this study, we propose an indium‐rich InGaN/GaN p‐i‐n thin‐film solar cell which incorporates a dual nanograting (NG) structure: Ag nanogratings (Ag‐NGs) on the backside of the solar cell and gallium nitride nanogratings (GaN‐NGs) on the frontside. Finite‐difference time‐domain (FDTD) simulation results show that the dual NG structure couples the incident sunlight to the plasmonic and photonic modes, thereby increasing the absorption of the solar cell in a broad spectral range. It is observed that the solar cells having the dual nanograting structures have a significant enhancement in light absorption as compared to cells having either no nanogratings or having only the frontside nanogratings or only the backside nanogratings. Analysis of light absorption in solar cells containing the dual NG structures showed that the absorption enhancement of longer wavelengths is mostly due to the Ag‐NGs on the backside and of shorter wavelengths is mostly due to the GaN‐NGs on frontside of the solar cell. The Jsc and power conversion efficiency (PCE) are calculated under AM1.5G solar illumination and are observed to be significantly enhanced due to the presence of optimized dual NG structures. While there is an increase in Jsc from 17.88 to 23.19 mA/cm2 (~30% enhancement), there is an increase in PCE from 15.49% to 20.24% (~31% enhancement) under unpolarized light (average of TM and TE). Moreover, the study of oblique light incidence shows significantly larger Jsc of the dual nanograting solar cells compared to the cells with no nanogratings.
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