21.0%-efficient screen-printed n-PERT back-junction silicon solar cell with plasma-deposited boron diffusion source

Wehmeier, Nadine; Nowack, Anja; Lim, Bianca; Brendemühl, Till; Kajari‐Schröder, Sarah; Schmidt, Jan; Brendel, Rolf; Dullweber, Thorsten

doi:10.1016/j.solmat.2016.05.054

Cited by 17 publications

(7 citation statements)

References 14 publications

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“…Screen-printing is a traditional and versatile printing method [1,2]. It is well established, not only in textile or poster printing, but also in the fabrication of all kinds of electronic devices, such as printed circuit boards [3,4], thin film transistors [5], displays, touch panels [6], low temperature co-fired ceramic devices [7,8], and photovoltaic cells [9,10]. Screen-printing is easy to implement and allows for high through-put, and is thus economically attractive for high-volume products like silicon (Si) solar cells.…”

Section: Introductionmentioning

confidence: 99%

Rheology and Screen-Printing Performance of Model Silver Pastes for Metallization of Si-Solar Cells

2018

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Further strong growth of solar energy conversion based on PV (photovoltaic) technology requires constant improvement to increase solar cell efficiency. The challenge in front-side metallization of Si-solar cells is to print uniform fine lines with a high aspect ratio to achieve higher efficiencies simultaneously with a reduced consumption of raw materials. An in-depth understanding of the relationship between paste composition, rheology and screen-printed line morphology is essential. Three model pastes with similar silver content and corresponding vehicles differing in their thixotropic agent content were investigated. Rheological properties (yield stress, viscosity, wall slip velocity, structural recovery, and fracture strain) were determined using steady and oscillatory shear, as well as elongational flow rheometry. Pastes were screen-printed at various speeds through a layout screen including line widths between 20 and 55 µm. Dried fingers were analyzed with respect to line width, aspect ratio (AR) and cross-sectional area. Our investigations reveal that minor changes of thixotropic agent result in substantial variations of the paste’s flow properties. However, this only weakly affects the line morphology. Irrespective of printing speed or finger opening, AR is slightly increasing; i.e., the screen-printing process is robust against changes in paste rheology.

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Section: Introductionmentioning

confidence: 99%

Rheology and Screen-Printing Performance of Model Silver Pastes for Metallization of Si-Solar Cells

2018

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“…We measure the quasi steady state photoconductance (QSSPC) of these samples using an intrinsic carrier concentration of Si of n i = 8.6 × 10 9 cm −3 . We achieve J 0 values of 40 fA cm −2 at boron sheet resistances R sheet between 90 and 108 Ω/sq applying the BSG/SiN z stacks as diffusion source and surface passivation . This compares to BBr 3 ‐diffused test wafers with AlO x /SiN y surface passivation exhibiting J 0 values of 14 fA cm −2 at boron sheet resistances R sheet 102 Ω/sq.…”

Section: Bicore Solar Cells With Bsg/sinzmentioning

confidence: 88%

“…Further details on the PECVD deposition parameters of the BSG/SiN z stack as well as on the POCl 3 co‐diffusion are published in Ref. . Finally, the test wafers are fired in a belt furnace with typical contact firing parameters.…”

Section: Bicore Solar Cells With Bsg/sinzmentioning

confidence: 99%

Industrial bifacial n‐type silicon solar cells applying a boron co‐diffused rear emitter and an aluminum rear finger grid

Dullweber

Wehmeier

Nowack

et al. 2016

Physica Status Solidi (a)

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The solar industry is introducing p-type monofacial passivated emitter and rear cells (PERC) into mass production. However, the efficiency of p-type PERC cells is subject to light-induced degradation (LID). In this paper, we introduce a novel solar cell design which we name BiCoRE as abbreviation of "bifacial co-diffused rear emitter." The BiCoRE cell process is very similar to the high volume proven PERC process sequence, but uses LID stable n-type wafers. A boron silicate glass (BSG) silicon nitride (SiN z ) stack at the rear side of the BiCoRE cells acts as protection layer against texturing and POCl 3 diffusion, as boron dopant source during the POCl 3 co-diffusion as well as passivation layer. The rear contacts are formed by laser contact opening (LCO) and screen printing of an Al finger grid similar to the recently introduced PERCþ solar cells. The Al finger grid enables bifaciality and results in up to 8.5 mm deep aluminum back surface fields (Al-BSFs) and up to 21.1% conversion efficiency obtained with n-type reference solar cells. The multifunctional BSG/SiN z stack demonstrates up to 20.6% conversion efficiency with BiCoRE solar cells. When illuminated from the rear side, the BiCoRE cells exhibit conversion efficiencies up to 16.1% which corresponds to a bifaciality of 78%.

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“…Typically, for silicon homojunction solar cells, the doping process to form a doped region in c-Si is based on thermal diffusion of dopant atoms from a dopant source, such as borosilicate-glass (BSG) or phosphosilicate-glass (PSG). − To avoid unwanted metal impurity contamination during thermal diffusion and the subsequent process steps, pre- and postcleaning processes are needed. For silicon heterojunction (SHJ) solar cells, n-type or p-type amorphous silicon (n,p-a-Si:H) is stacked on intrinsic a-Si:H (i-a-Si:H).…”

Section: Introductionmentioning

confidence: 99%

Low Work Function Ytterbium Silicide Contact for Doping-Free Silicon Solar Cells

Cho

Radhakrishnan

Payo

et al. 2020

ACS Appl. Energy Mater.

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Metal silicide is a well-known material for contact layers, however, it has not been tested in the context of doping-free carrier selective contacts. Thin film deposition of an appropriate metal with mild annealing treatment is an interesting alternative to the more complex depositions of other compound materials. Reaction of Yb deposited on top an i-a-Si:H passivation layer results in the formation of YbSix on top of a remnant i-a-Si:H following a low-temperature anneal below 200 °C. Such a contact is an interesting candidate as a doping-free electron-selective contact. Detailed investigation of the i-a-Si/YbSix contact shows that Yb thickness, i-a-Si:H thickness and silicidation annealing conditions play a significant role in determining the recombination current density (J0,metal) and the contact resistivity (ρc). Low J0,metal of 5 fA/cm 2 and low ρc below 0.1 Ω.cm were independently demonstrated for such ia-Si:H/YbSix contacts. We also demonstrate that low-temperature silicidation can be combined with

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21.0%-efficient screen-printed n-PERT back-junction silicon solar cell with plasma-deposited boron diffusion source

Cited by 17 publications

References 14 publications

Rheology and Screen-Printing Performance of Model Silver Pastes for Metallization of Si-Solar Cells

Rheology and Screen-Printing Performance of Model Silver Pastes for Metallization of Si-Solar Cells

Industrial bifacial n‐type silicon solar cells applying a boron co‐diffused rear emitter and an aluminum rear finger grid

Low Work Function Ytterbium Silicide Contact for Doping-Free Silicon Solar Cells

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