Large area tunnel oxide passivated rear contact <i>n</i>‐type Si solar cells with 21.2% efficiency

Tao, Yuguo; Upadhyaya, Vijaykumar; Chen, Chia-Wei; Payne, Adam; Chang, Elizabeth; Upadhyaya, Ajay; Rohatgi, A.

doi:10.1002/pip.2739

Cited by 82 publications

(29 citation statements)

References 30 publications

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“…In this case, for example, a high‐temperature firing process is required to enable the conductive metal electrode material to penetrate the dielectric layers, which forms a local transport path. [ 15,16 ] In addition, the deposition of dielectric passivation materials always requires high‐vacuum equipment, such as plasma‐enhanced chemical vapor deposition (PECVD) and atomic layer deposition (ALD). Thus, for the future development of low‐cost clean energy sources, a new technical strategy, i.e., using only one material that can passivate interfacial electron traps while conducting carriers, is needed.…”

Section: Introductionmentioning

confidence: 99%

Conductive Hole‐Selective Passivating Contacts for Crystalline Silicon Solar Cells

Wan

Zhang

et al. 2020

Advanced Energy Materials

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Defect state passivation and conductivity of materials are always in opposition; thus, it is unlikely for one material to possess both excellent carrier transport and defect state passivation simultaneously. As a result, the use of partial passivation and local contact strategies are required for silicon solar cells, which leads to fabrication processes with technical complexities. Thus, one material that possesses both a good passivation and conductivity is highly desirable in silicon photovoltaic (PV) cells. In this work, a passivation‐conductivity phase‐like diagram is presented and a conductive‐passivating‐carrier‐selective contact is achieved using PEDOT:Nafion composite thin films. A power conversion efficiency of 18.8% is reported for an industrial multicrystalline silicon solar cell with a back PEDOT:Nafion contact, demonstrating a solution‐processed organic passivating contact concept. This concept has the potential advantages of omitting the use of conventional dielectric passivation materials deposited by costly high‐vacuum equipment, energy‐intensive high‐temperature processes, and complex laser opening steps. This work also contributes an effective back‐surface field scheme and a new hole‐selective contact for p‐type and n‐type silicon solar cells, respectively, both for research purposes and as a low‐cost surface engineering strategy for future Si‐based PV technologies.

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Section: Introductionmentioning

confidence: 99%

Conductive Hole‐Selective Passivating Contacts for Crystalline Silicon Solar Cells

Wan

Zhang

et al. 2020

Advanced Energy Materials

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“…An example of a bifacial, n ‐type, large‐area (ie, 239 cm 2 ), screen‐printed, passivating contact cell demonstrating efficiencies up to 21.3% using fire‐through metallization on the front and rear sides can be found in the study of Stodolny et al The highest cell efficiency found in the literature for a large‐area (ie, 244.3 cm 2 ), bifacial, passivating contact cell with screen‐printed, and fired metal contacts is currently at 21.5% . On the other hand, an n ‐type, large‐area, monofacial solar cell with an efficiency of 21.4% was reported with a screen‐printed front but with full‐area thermally evaporated silver (Ag) on the rear . Hybrid schemes that use a passivating contact capped by transparent conductive oxides (TCOs) recently demonstrated a best cell efficiency of 22.3% on large‐area cells; however, it must be noted that these cells use low‐temperature screen‐printed Ag metallization at the front and rear .…”

Section: Introductionmentioning

confidence: 99%

“…21 On the other hand, an n-type, large-area, monofacial solar cell with an efficiency of 21.4% was reported with a screen-printed front but with full-area thermally evaporated silver (Ag) on the rear. 22 Hybrid schemes that use a passivating contact capped by transparent conductive oxides (TCOs) recently demonstrated a best cell efficiency of 22.3% on large-area cells; however, it must be noted that these cells use low-temperature screen-printed Ag metallization at the front and rear. 23 Hence, there is still some work needed to make passivating contact cell technology accessible to the current PV industry where high-temperature screen-printed metallization schemes dominate.…”

Section: Introductionmentioning

confidence: 99%

Approaching 23% with large‐area monoPoly cells using screen‐printed and fired rear passivating contacts fabricated by inline PECVD

Nandakumar

Rodriguez

Kluge

et al. 2018

Progress in Photovoltaics

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We present n‐type bifacial solar cells with a rear interfacial SiOx/n+:poly‐Si passivating contact (‘monoPoly’ cells) where the interfacial oxide and n+:poly‐Si layers are fabricated using an industrial inline plasma‐enhanced chemical vapor deposition (PECVD) tool. We demonstrate outstanding passivation quality with dark saturation current density (J0) values of approximately 3 fA/cm2 and implied open‐circuit voltage (iVoc) of 730 mV at 1‐sun conditions after firing in an industrial belt furnace. Using a simple solar cell process flow that can be easily adapted for mass production, a peak cell efficiency of 22.8% with a cell open circuit voltage (Voc) of 696 mV is achieved on large‐area, screen‐printed, Czochralski‐silicon (Cz‐Si) solar cells using commercial fire‐through metal pastes.

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“…In recent years, passivating and carrier-selective contacts have pushed the efficiency of crystalline silicon (c-Si) solar cells to new record efficiencies. [1][2][3][4][5][6] One of the most promising approaches to such structures is the tunnel oxide passivated contact (TOPCon) process, which utilizes an ultrathin interfacial oxide (12-15 Å) at the interface in combination with a heavily doped silicon (poly-Si) or a silicon-rich silicon carbide (SiC x ) thin film. Tube furnace direct plasma-enhanced chemical vapor deposition (PECVD) reactors can be an appealing technology enabling high throughput deposition of the silicon thin film.…”

Section: Introductionmentioning

confidence: 99%

Excellent Surface Passivation Quality on Crystalline Silicon Using Industrial‐Scale Direct‐Plasma TOPCon Deposition Technology

et al. 2018

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Passivating contacts based on a thin SiOx layer and a doped Si layer (TOPCon) are an appealing choice for pushing the efficiency of Si solar cells. One way to deposit the doped Si layer is to utilize radio‐frequency direct plasma‐enhanced chemical vapor deposition as commonly used in industry for the deposition of silicon nitride. However, due to the low operating frequency in the kHz range, there are concerns that ion bombardment might damage the thin SiOx layer and thus prevent suitable surface passivation. We demonstrate that this is not the case. Instead, the application of these layers on c‐Si results in excellent surface passivation. Minority carrier lifetimes exceeding the intrinsic bulk limit predicted by current models on 1 Ω cm n‐type were observed, out‐performing the reference layers. The excellent surface passivation results in an implied VOC of above 735 mV and an implied FF of almost 88% on 200 µm thick n‐type c‐Si. Furthermore, a lifetime test on 100 Ω cm n‐type c‐Si revealed an extraordinary lifetime of 190 ms (Δn = 1 × 1014 cm−3).

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Large area tunnel oxide passivated rear contact n‐type Si solar cells with 21.2% efficiency

Cited by 82 publications

References 30 publications

Conductive Hole‐Selective Passivating Contacts for Crystalline Silicon Solar Cells

Conductive Hole‐Selective Passivating Contacts for Crystalline Silicon Solar Cells

Approaching 23% with large‐area monoPoly cells using screen‐printed and fired rear passivating contacts fabricated by inline PECVD

Excellent Surface Passivation Quality on Crystalline Silicon Using Industrial‐Scale Direct‐Plasma TOPCon Deposition Technology

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