Efficiency enhancement of bifacial PERC solar cells with laser‐doped selective emitter and double‐screen‐printed Al grid

Wu, Wei; Zhang, Zhongwei; Zheng, Fei; Lin, Wei; Liang, Zongcun; Shen, Hui

doi:10.1002/pip.3013

Cited by 27 publications

(12 citation statements)

References 31 publications

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“…Thus, the suppression of carrier recombination at Si surfaces using passivation technologies is imperative for applications in Si semiconductor devices with good performance. Materials such as hydrogenated amorphous silicon (a-Si:H) and aluminum oxide (Al 2 O 3 ) in the industry and a range of recently reported transition or post-transition metal oxides, including titanium oxide, hafnium oxide, gallium oxide, tantalum oxide, and zirconium oxide, have been demonstrated to possess effective passivation of Si. − Among these passivation schemes, the passivation effects of a-Si:H and Al 2 O 3 are preferable, with very high effective minority carrier lifetimes (τ eff ) of ∼10 ms on Si wafers with a resistivity of 1–5 Ω·cm. , Thus, PCE over 25% can be achieved by a-Si:H or Al 2 O 3 passivation, for example, a Si heterojunction solar cell and passivated emitter and rear contact solar cell. , …”

Section: Introductionmentioning

confidence: 99%

“…6,7 Thus, PCE over 25% can be achieved by a-Si:H or Al 2 O 3 passivation, for example, a Si heterojunction solar cell and passivated emitter and rear contact solar cell. 2,12 However, the above-mentioned passivation schemes require vacuum technologies, such as plasma-enhanced chemical vapor deposition (CVD) and atomic layer deposition. High-vacuum deposition equipment is a heavy investment that makes the production line for Si solar cells very expensive.…”

Section: ■ Introductionmentioning

confidence: 99%

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Vacuum-Free, Room-Temperature Organic Passivation of Silicon: Toward Very Low Recombination of Micro-/Nanotextured Surface Structures

Chen

Zhang

et al. 2018

ACS Appl. Mater. Interfaces

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Crystalline silicon (c-Si) solar cells remain dominant in the photovoltaic (PV) market because of their cost-effective advantages. However, the requirement for expensive vacuum equipment and the power-hungry thermal budget for surface passivation technology, which is one of the key enablers of the high performance of c-Si solar cells, impede further reductions of costs. Thus, the omission of the vacuum and high-temperature process without compromising the passivation effect is highly desirable due to cost concerns. Here, we demonstrate a vacuum-free, room-temperature organic Nafion thin-film passivation scheme with an effective minority carrier lifetime (τ eff ) exceeding 9 ms on an n-type c-Si wafer with a resistivity of 1−5 Ω•cm, corresponding to an implied open circuit voltage (iV oc ) of 724 mV and upper-limit surface recombination velocity (SRV) of 1.46 cm/s, which is a level that is in line with the hydrogenated amorphous Si film-passivation scheme used in the current PV industry. We find that the Nafion film passivation of Si can be enhanced in an O 2 atmosphere and that the Nafion/c-Si interface oxidation should be responsible for the passivation mechanism. This highly effective passivation is also achieved on various micro-/nanotextured Si surface structures from actual production, including a pyramidal surface and nanopore−pyramid hybrid structure with nanopores on the inclined plane of the pyramid. We develop an organic Nafion-passivated n-type back-junction Si solar cell to examine application in a real device. The open circuit voltage (V oc ) of the solar cell with the Nafion passivation layer achieves a clear improvement (30.8 mV) over those without the passivation layer, resulting in an increase (1.5%) in the power conversion efficiency. These results suggest the potential use of these organic electronics with current Si microelectronics and a new strategy for the development of vacuum-free, low-temperature Si-based PVs at low cost.

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Section: Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Vacuum-Free, Room-Temperature Organic Passivation of Silicon: Toward Very Low Recombination of Micro-/Nanotextured Surface Structures

Chen

Zhang

et al. 2018

ACS Appl. Mater. Interfaces

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“…In recent years, the laser‐doping selective emitter (LDSE) technique has been widely used in silicon solar cell fabrication because of its simple, low‐cost, and high‐throughput characteristics 10–12 . After laser doping, the phosohosilicate glass (PSG) layer in the doped region is usually damaged or thinned due to laser irradiation.…”

Section: Introductionmentioning

confidence: 99%

“…[7][8][9] In recent years, the laser-doping selective emitter (LDSE) technique has been widely used in silicon solar cell fabrication because of its simple, low-cost, and high-throughput characteristics. [10][11][12] After laser doping, the phosohosilicate glass (PSG) layer in the doped region is usually damaged or thinned due to laser irradiation. Referring to an existing approach to industrial monocrystalline silicon PERC solar cells with a selective emitter (mono-PERC-SE solar cells), after alkaline double-sided texturing-POCl 3 diffusion-laser doping process sequence, acidic (HF/HNO 3 ) wet chemical polishing by using an inline process partly removes the random pyramid texture on the rear side of the wafers.…”

Section: Introductionmentioning

confidence: 99%

A solid strategy to realize heteroface selective emitter and rear passivated silicon solar cells

Zou

Ding

et al. 2022

Progress in Photovoltaics

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Passivated emitter and rear cell (PERC) with laser‐doped selective emitter (SE) has become mainstream in the PV industry. In this work, we report a solid strategy to realize heteroface monocrystalline silicon (mono‐Si) wafers for PERC‐SE solar cells by employing alkaline polishing to form a polished surface for the rear side and well‐established metal‐catalyzed chemical etching to form a honeycomb texture for the front side in one wet process successively. The key to success lies in the fact that the two back‐to‐back wafers inserted into one slot in the cassette are tightly attached together in MCCE etching so that only the exposed surfaces are etched to form textures, while the rear polished surfaces are still retained to avoid wrap‐around etching. With the strategy, the mono‐Si PERC‐SE solar cells achieve an average efficiency of over 22.0%, no poorer than that of the reference system (traditional alkaline texturing and rear acidic polishing), and have good light trapping capability for oblique incident light. Moreover, the total Si removal in the novel process is only ~0.4 g, which is far less than that in the traditional process. More importantly, the strategy can also double the throughput of existing texturing processes and significantly reduce the amount of etching waste. Therefore, the work is expected to provide a promising way to mass produce efficient mono‐Si PERC‐SE solar cells with a superior rear surface, achieved without increasing the number of processing steps, and lower cost.

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“…The solar industry has been attracting attention as a future energy source, and the demand and supply market for crystalline silicon (c-Si) solar cells has been gradually expanding. However, the maximum efficiency of conventional c-Si solar cell fabrication technology is limited, so it is necessary to study this technology in order to improve its efficiency [1][2][3]. Currently, new methods of increasing efficiency involve cell design modifications using selective emitters [4].…”

Section: Introductionmentioning

confidence: 99%

Effects of Laser Doping on the Formation of the Selective Emitter of a c-Si Solar Cell

et al. 2020

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Laser doping, though able to improve cell characteristics, enables the formation of a selective emitter without the need for additional processing. Its parameters should be investigated to minimize laser defects, such as the heat-affected zone (HAZ), and to obtain a low contact resistance. Herein, the laser fluence and speed were changed to optimize process conditions. Under a laser fluence of 1.77 J/cm2 or more, the surface deteriorated due to the formation of the HAZ during the formation of the laser doping selective emitter (LDSE). The HAZ prevented the formation of the LDSE and impaired cell characteristics. Therefore, the laser speeds were changed from 10 to 70 mm/s. The lowest contact resistivity of 1.8 mΩ·cm2 was obtained under a laser fluence and speed of 1.29 J/cm2 and 10 mm/s, respectively. However, the surface had an irregular structure due to the melting phenomenon, and many by-products were formed. This may have degraded the efficiency due to the increased contact reflectivity. Thus, we obtained the lowest contact resistivity of 3.42 mΩ·cm2, and the damage was minimized under the laser fluence and speed of 1.29 J/cm2 and 40 mm/s, respectively.

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Efficiency enhancement of bifacial PERC solar cells with laser‐doped selective emitter and double‐screen‐printed Al grid

Cited by 27 publications

References 31 publications

Vacuum-Free, Room-Temperature Organic Passivation of Silicon: Toward Very Low Recombination of Micro-/Nanotextured Surface Structures

Vacuum-Free, Room-Temperature Organic Passivation of Silicon: Toward Very Low Recombination of Micro-/Nanotextured Surface Structures

A solid strategy to realize heteroface selective emitter and rear passivated silicon solar cells

Effects of Laser Doping on the Formation of the Selective Emitter of a c-Si Solar Cell

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