Heterojunction solar cells with 23% efficiency on<i>n</i>-type epitaxial kerfless silicon wafers

Kobayashi, Eiji; Watabe, Y.; Hao, Ruiying; Ravi, T. S.

doi:10.1002/pip.2813

Cited by 16 publications

(9 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2 In recent years, a-Si:H layers also garnered significant attention, thanks to their excellent crystalline silicon (c-Si) surface passivation properties, even when only a few nm thin. [3][4][5][6][7][8] This property is exploited with remarkable success for passivating-contact fabrication in silicon heterojunction (SHJ) solar cells, [9][10][11][12][13][14][15][16][17][18][19][20][21][22] with reported conversion cell efficiencies as high as 26.3%. 23 For any solar cell technology, an important criterion for ultimate device performance is its stability under prolonged light exposure.…”

mentioning

confidence: 99%

Light-induced performance increase of silicon heterojunction solar cells

Kobayashi

Wolf

Levrat

et al. 2016

Applied Physics Letters

Self Cite

View full text Add to dashboard Cite

Silicon heterojunction solar cells consist of crystalline silicon (c-Si) wafers coated with doped/intrinsic hydrogenated amorphous silicon (a-Si:H) bilayers for passivating-contact formation. Here, we unambiguously demonstrate that carrier injection either due to light soaking or (dark) forward-voltage bias increases the open circuit voltage and fill factor of finished cells, leading to a conversion efficiency gain of up to 0.3% absolute. This phenomenon contrasts markedly with the light-induced degradation known for thin-film a-Si:H solar cells. We associate our performance gain with an increase in surface passivation, which we find is specific to doped a-Si:H/c-Si structures. Our experiments suggest that this improvement originates from a reduced density of recombination-active interface states. To understand the time dependence of the observed phenomena, a kinetic model is presented.

show abstract

mentioning

confidence: 99%

Light-induced performance increase of silicon heterojunction solar cells

Kobayashi

Wolf

Levrat

et al. 2016

Applied Physics Letters

Self Cite

View full text Add to dashboard Cite

show abstract

“…Another reason being the minimal parasitic absorption by the MoO x layer due to its large energy band gap (≈3.2 eV) in comparison to the conventional SHJ with the highly absorbing a‐Si:H(i) layers (≈1.7 eV) . Also, the thicker layers are required for better surface passivation in conventional SHJ, which can affect the electrical properties of the cell by showing non‐ideal electrical behavior apart from the parasitic absorption loss …”

Section: Resultsmentioning

confidence: 99%

Carrier‐Selective Contact Based Silicon Solar Cells Processed at Room Temperature using Industrially Feasible Cz Wafers

Nayak

Singh

Mudgal

et al. 2019

Physica Status Solidi (a)

View full text Add to dashboard Cite

For the broad use of solar photovoltaic devices, the device fabricated at commercially viable silicon wafers at room temperature is more preferable to harvest abundant solar energy. Silicon heterojunction solar cells at room temperature, based on carrier-selective layers without using any specified surface passivation layer on the silicon wafer is fabricated. Industrially feasible Cz n-type non-textured silicon wafers having the bulk lifetime of 300 ms are used for cell fabrication. The molybdenum oxide (MoO x ) and lithium fluoride (LiF x ) are used as hole-and electron-selective layers, respectively. The highest conversion efficiency of >15% from the simple architecture of Ag/TCO/MoO x /n-Si/LiF x /Al is achieved. The internal quantum efficiency of %96% is observed in the shorter wavelength region, whereas to understand relatively less response between 800 and 1100 nm wavelength region; effective minority carrier diffusion lengths are estimated. The authors also confirm the inversion layer formation in the silicon after MoO x contact from temperature dependent capacitance-voltage measurements, and quantify the crucial built-in-potential of %0.69 V from the cell structure due to the high work function of MoO x layer.

show abstract

“…This 2D majority carrier transport effect leads to less restriction on the conductivity of front TCO layer for the rear emitter SHJ solar cell compared with its front emitter counterpart . Therefore, suppressing the light absorption in the front TCO layer should be more important in improving the efficiency of the rear emitter cell.…”

Section: Resultsmentioning

confidence: 99%

“…Recently, based on the design of the rear emitter cell, Watahiki et al have successfully realized a 23.43% efficient SHJ solar cell by utilizing an n‐type microcrystalline Si layer as the window layer instead of the normally used a‐Si:H(n) layer. Kobayashi et al have reported a rear emitter SHJ solar cell with an efficiency of 23% using an epitaxial kerfless silicon wafer substrate. However, it should be noted that the research work on the rear emitter SHJ solar cell is still limited and there lacks a competitive study for deep understanding of the design principle and process optimization of the rear emitter SHJ solar cell.…”

Section: Introductionmentioning

confidence: 99%

Study and development of rear‐emitter Si heterojunction solar cells and application of direct copper metallization

Yang

Zhong

Zhang

et al. 2018

Progress in Photovoltaics

View full text Add to dashboard Cite

We have presented a comprehensive study on the development of rear emitter silicon heterojunction (SHJ) solar cells, which shows more freedom for device optimization than the standard front emitter SHJ counterparts. The optimization of the p-type hydrogenated amorphous silicon (a-Si:H(p)) layer is liberated from the parasitic absorption issue, while the n-type hydrogenated amorphous silicon (a-Si:H(n)) layer is optimized considering the tradeoff between the light absorption loss and field-effect passivation. The front transparent conductive oxide (TCO) layer can be designed stressing on its optical properties because the lateral transport of the majority carriers at the front side of the cell is supported by the Si substrate, while the rear TCO layer is free to be tuned for suppressing the TCO/a-Si:H(p) contact resistance. A rear emitter SHJ solar cell (225.47 cm 2 ) fabricated by industry compatible process has been achieved with an efficiency of over 22%. We have further demonstrated the replacement of screen-printed silver metallization with a low cost direct copper metallization in the rear emitter SHJ solar cells. We report an exciting 22.06% cell efficiency which is comparable to that of the screen-printed counterpart.

show abstract

Heterojunction solar cells with 23% efficiency onn-type epitaxial kerfless silicon wafers

Cited by 16 publications

References 35 publications

Light-induced performance increase of silicon heterojunction solar cells

Light-induced performance increase of silicon heterojunction solar cells

Carrier‐Selective Contact Based Silicon Solar Cells Processed at Room Temperature using Industrially Feasible Cz Wafers

Study and development of rear‐emitter Si heterojunction solar cells and application of direct copper metallization

Contact Info

Product

Resources

About