ZEBRA technology: low cost bifacial IBC solar cells in mass production with efficiency exceeding 23.5%

Kopecek, Radovan; Libal, Joris; Lossen, J.; Mihailetchi, Valentin D.; Chu, Haifeng; Peter, Christoph; Buchholz, Florian; Wefringhaus, E.; Halm, A.; Ma, Jikui; Liu, Jianda; Guo, Yonggang; Qu, Xiaoyong; Wu, Xiang; Peng, Dongdong

doi:10.1109/pvsc45281.2020.9300503

Cited by 32 publications

(39 citation statements)

References 4 publications

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“…For instance, silicon bottom cell of 3T tandem decreased the V oc from 0.565 V (100 mW cm −2 ) to 0.081 V at 1.5 mW cm −2 , while single‐junction silicon solar cells can maintain around 500 mV (1.5 mW cm −2 ) owing to the front surface passivation layer (e.g., SiNx). [ 22 ] Regarding the perovskite top cells, the V oc sensitivity is lower than the single‐junction perovskite solar cells. This might be due to the reduced ideal diode factor by the TCO sputtering damage on the HTL.…”

Section: Resultsmentioning

confidence: 99%

“…The IBC cell concept used in this study is based on ISC‐Konstanz's ZEBRA cell technology that is currently in mass production with an average conversion efficiency exceeding 23.5%. [ 22 ] The IBC cells were fabricated on M2 (156.75 mm) n‐type Cz wafers with a resistivity range of 4–7 Ωcm and a thickness of 170 ± 10 µm. The fabrication process sequence of IBC cells for tandem integration follows that used in mass production, [ 22 ] with only minor process adaptations.…”

Section: Methodsmentioning

confidence: 99%

“…[ 22 ] The IBC cells were fabricated on M2 (156.75 mm) n‐type Cz wafers with a resistivity range of 4–7 Ωcm and a thickness of 170 ± 10 µm. The fabrication process sequence of IBC cells for tandem integration follows that used in mass production, [ 22 ] with only minor process adaptations. It uses high‐temperature Boron and Phosphorous diffusions to form the 150 ± 15 Ω/sq p + and n + doped regions, thermal SiO 2 and PECVD SiNx deposition for surface passivation stack, as well as screen printing and firing‐through metallization steps.…”

Section: Methodsmentioning

confidence: 99%

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Three‐terminal perovskite/integrated back contact silicon tandem solar cells under low light intensity conditions

Kanda

Mihailetchi

Gueunier‐Farret

et al. 2022

Interdisciplinary Materials

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The current climate and energy crisis urgently needs solar cells with efficiencies above the 29% single junction efficiency bottleneck. Silicon/perovskite tandem solar cells are a solution, which is attracting much attention. While silicon/perovskite tandem cells in 2-terminal and 4-terminal configurations are well documented, the three-terminal concept is still in its infancy. It has significant advantages under low light intensities as opposed to concentrated sunlight, which is the critical factor in designing tandem solar cells for low-cost terrestrial applications. This study presents novel studies of the sub-cell performance of the first three-terminal perovskite/silicon selective band offset barrier tandem solar cells fabricated in an ongoing research project. This study focuses on short circuit current and operating voltages of the sub-cells under light intensities of one sun and below. Lifetime studies show that the perovskite bulk carrier lifetime is insensitive to illumination, while the silicon cell's lifetime decreases with decreasing light intensity. The combination of perovskite and silicon in the 3T perovskite-silicon tandem therefore reduces the sensitivity of V OC to light intensity and maintains a relatively higher V OC down to low light intensities, whereas silicon single-junction cells show a marked decrease. This technological advantage is proposed as a novel advantage

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Three‐terminal perovskite/integrated back contact silicon tandem solar cells under low light intensity conditions

Kanda

Mihailetchi

Gueunier‐Farret

et al. 2022

Interdisciplinary Materials

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show abstract

“…Such reduction can be achieved from the reduction of production and installation costs and optimizing the power output of solar cells and modules 4 . Based on the above two aspects, many new technologies, solar cells, and modules have been developed in recent years 5‐7 . But more PV companies and researchers 8‐11 focused on the research and manufacturing of Si‐based bifacial and passivated emitter and rear cells solar cells and modules because it will become a mainstream application of technology, although most of the advancing cell technology has a better theoretical advantage.…”

Section: Introductionmentioning

confidence: 99%

Influence of laser condition on the electrical and mechanical performance of bifacial half‐cutting PERC solar cell and module

Zhang

Shen

Liu³

et al. 2022

Intl J of Energy Research

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Summary In recent years, the laser half‐cutting technology for silicon solar cells has gotten much attention from researchers for increasing module power and would become particularly important in the photovoltaic modules domain. Herein, this paper would introduce a kind of new laser cutting process, a thermal laser separation (TLS) cutting technology. In the laser cutting processes, the influence on mechanical and electrical characteristics of bifacial p‐type passivated emitter and rear (PERC) solar cell and module were investigated in considerable detail. We have made a series of research and analyses including the cutting principle, opening length, fracture surface, and hot influence zone. The results reveal that the TLS cutting process could reduce damage more than the regular laser scribing and cleaving (LSC) cutting process. The TLS cutting process would achieve the higher power of a PERC half‐cutting bifacial module and the stronger bending strength of half solar cells than the LSC cutting process.

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“…IBC solar cells are a very promising architecture for Si PV due to their high short-circuit current density, J sc , which is due to the lack of front shading loss and no parasitic absorption from a-Si:H or poly-Si at the front of the device. IBC cells can also be made bifacial, − and thus have great potential to enter the mainstream Si PV market. However, more cost-effective, simpler processing techniques are needed, especially for forming highly passivated IBC finger structures at the back of the cell with no shunting.…”

Section: Introductionmentioning

confidence: 99%

Trap-Assisted Dopant Compensation Prevents Shunting in Poly-Si Passivating Interdigitated Back Contact Silicon Solar Cells

Hartenstein

Stetson

Nemeth

et al. 2021

ACS Appl. Energy Mater.

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Using a trap-assisted compensation model, we explain why polycrystalline Si (poly-Si) passivating contacts are able to achieve low leakage current between the doped fingers of interdigitated back contact (IBC) monocrystalline Si solar cells despite mixing of boron and phosphorus dopants in the isolation region. The fill factor of IBC solar cells is strongly affected by the electrical isolation region between n- and p-type fingers, as this region is critical in minimizing shunting losses. During fabrication of monocrystalline Si solar cells with poly-Si passivating contacts, the intrinsic poly-Si isolation region inevitably gets contaminated with both p- and n-type dopants. Using dopant profiles measured with time-of-flight secondary ion mass spectrometry and scanning probe measurements of the isolation region, we demonstrate that despite the dopant spreading during cell processing, a well-compensated region between the doped fingers exists that prevents shunting. The trap-assisted dopant compensation mechanism significantly widens the compensated region to tens of microns, where the residual dopant densities are below the trap density. This enables a high-resistivity region, resulting in low shunt current. Using one-dimensional (1-D) finite element diode simulations, we identify the design parameters and experimental conditions under which a sufficiently resistive region can form. Our measurements of 2-D local resistivity and work function maps across the isolation region using scanning spreading resistance microscopy and Kelvin probe force microscopy demonstrate the existence of a highly resistive, wide compensated region and confirm our proposed compensation mechanism. For our structures, this region is ∼25 μm in width within a ∼150 μm wide finger isolation region with nearly 3 orders of magnitude higher resistivity than the regions dominated by a single type of dopant.

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ZEBRA technology: low cost bifacial IBC solar cells in mass production with efficiency exceeding 23.5%

Cited by 32 publications

References 4 publications

Three‐terminal perovskite/integrated back contact silicon tandem solar cells under low light intensity conditions

Three‐terminal perovskite/integrated back contact silicon tandem solar cells under low light intensity conditions

Influence of laser condition on the electrical and mechanical performance of bifacial half‐cutting PERC solar cell and module

Trap-Assisted Dopant Compensation Prevents Shunting in Poly-Si Passivating Interdigitated Back Contact Silicon Solar Cells

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