Laser‐enhanced contact optimization on <i>i</i>TOPCon solar cells

Fellmeth, Tobias; Höffler, Hannes; Mack, Sebastian; Krassowski, Eve; Krieg, Katrin; Kafle, Bishal; Greulich, Johannes

doi:10.1002/pip.3598

Cited by 15 publications

(9 citation statements)

References 26 publications

(51 reference statements)

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“…At least for what we describe as “standard firing temperature,” we can further improve the fill factor and solar cell efficiency with laser‐enhanced contact optimization (LECO). [ 10 ] The method allows reducing the contact resistance of paste contacts fired at elevated temperatures and benefits from reduced firing temperatures to obtain high V OC after metallization. Applying this technology, we see reproducibly FF improvement of 0.5–1.5% absolute.…”

Section: Methodsmentioning

confidence: 99%

High Lifetime Ga‐Doped Cz‐Si for Carrier‐Selective Junction Solar Cells

et al. 2022

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Industrial mass production of solar cells is at a transition toward carrier‐selective junction solar cells with passivating contacts such as TOPCon, POLO, or heterojunction technology (HJT). At the same time, many manufacturers consider switching from p‐type Cz‐Si to n‐type Cz‐Si wafers. This contribution indicates that Ga‐doped p‐type Cz‐Si material is still a viable option for the new type of devices while giving an opportunity to benefit from lower wafer cost. The minority carrier diffusion lengths that are an order of magnitude larger than the thickness of the studied HJT and TOPCoRE devices are reported. Stability aspects for operation in the field are discussed. Best TOPCoRE solar cells on Ga‐doped Cz‐Si show a 0.2% higher efficiency than their co‐processed n‐type counterparts.

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Section: Methodsmentioning

confidence: 99%

High Lifetime Ga‐Doped Cz‐Si for Carrier‐Selective Junction Solar Cells

et al. 2022

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“…In 2021 the first evaluation of the impact of LECO on the module output in industrial scale and on the modulereliability was presented [5] À where shorter-term effects have been analysed. In autumn 2022 also results of LECO on TOPCon cells have been shown [6].…”

Section: Introductionmentioning

confidence: 92%

“…Combining both observations, the real benefit for an end-customer can be presumed: considering an efficiency increase potential of +0.6% (abs. for TOPCon À [6]) which is a 2.5% relative gain, a typical private home PV installation of 10 kWp would improve to 10.25 kWp. For typical value of 1.000 kWh/kWp an extra energy of 250 kWh/year can be generated À which can for example be used to power one standard refrigerator for the entire year.…”

Section: Leco Conceptmentioning

confidence: 99%

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Assessing the long-term stability of laser enhanced contact optimization (LECO) treated PERC cells in PV modules by extended indoor and outdoor durability tests

et al. 2023

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It was previously shown that the Laser Enhanced Contact Optimization (LECO) Process is a promising boost for PERC and TOPCon cell manufacturing enhancement. In this contribution, a method is developed to assess the long-term stability of industrial LECO treated PERC cells in a module compound. Therefore, extended accelerated aging tests as well as outdoor measurements were performed on modules comprising LECO treated cells as well as untreated references. It is described, how data can be evaluated to separate typical, known aging and degradation effects from presumable LECO specific effects. The results of this work show that test modules comprising LECO treated cells did not show a different behavior in the accelerated aging or degradation compared to the reference. The same conclusion was found for thermal cycling and damp heat tests, both far in excess of IEC requirements, as well as in a sequential test sequence. In addition, their outdoor performance with local and integral measurements has been evaluated. We can conclude that for the tested PERC cells, aging and degradation effects appeared, but none of them could be attributed to the LECO process. Hence, improvements in the efficiency and/or yield on cell level due to LECO can be translated to the module or even system level considering typical aging and degradation behavior, independently of a prior LECO process.

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“…The implementation of boron diffusion from APCVD BSG layers into solar cell processing in combination with single slot and stacked configuration yields the solar cell current voltage (IV) parameters shown in Fig. 9 as box plots measured by an industrial cell tester (grid touch unit for the 0BB front side metallization and a nonreflective rear side chuck) after laser enhanced contact optimization (LECO) [24], [25]. The reference sequence using BBr 3 diffusion yields a median energy conversion efficiency of η = (22.6 ± 0.2)% with a peak energy conversion efficiency of η = 22.9%.…”

Section: B Solar Cell Fabricationmentioning

confidence: 99%

Stack Diffusion Process for Cost- and Energy-Efficient Boron Emitter Formation

Meßmer

Bashardoust

Belledin

et al. 2022

IEEE J. Photovoltaics

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The boron emitter formation for tunnel oxide passivated contact (TOPCon) solar cells faces higher costs compared to the POCl 3 diffusion for passivated emitter and rear (PERC) solar cells due to the requirement for higher temperatures and longer process times. This work presents an alternative energy-efficient and low cost of ownership boron diffusion approach for TOPCon solar cells, enabling a highly increased throughput compared to the typically used gas phase diffusion. We use an atmospheric pressure chemical vapor deposition borosilicate glass layer as the boron dopant source and combine it with a subsequent thermal anneal in a quartz tube furnace for dopant drive-in. Here, we either use a conventional single-slot quartz boat configuration, or, for highly increased throughput, a vertical wafer stack configuration with the wafer surfaces in direct contact with each other. We show that this approach yields an emitter doping profile comparable to the state-of-the-art gas phase diffusion with sufficient uniformity across the wafer area. We further investigate the emitter dark saturation current densities j 0e as well as the energy conversion efficiency of TOPCon solar cells fabricated for each configuration and compare the results to those of a BBr 3 reference process. These solar cells achieve energy conversion efficiencies exceeding 23% for the stack diffusion approach. Additionally, we demonstrate a potential reduction in both the cost of ownership and the specific electricity consumption of the presented approach.Index Terms-Atmospheric pressure chemical vapor deposition (APCVD), borosilicate glass (BSG), BBr 3 , boron diffusion, high throughput, stack diffusion, tunnel oxide passivated contact (TOPCon). I. INTRODUCTIONP ASSIVATED contacts on n-type monocrystalline silicon wafers are widely seen as the forthcoming cell technology. Within this decade, this technology is expected to gain a Manuscript

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Laser‐enhanced contact optimization on iTOPCon solar cells

Cited by 15 publications

References 26 publications

High Lifetime Ga‐Doped Cz‐Si for Carrier‐Selective Junction Solar Cells

High Lifetime Ga‐Doped Cz‐Si for Carrier‐Selective Junction Solar Cells

Assessing the long-term stability of laser enhanced contact optimization (LECO) treated PERC cells in PV modules by extended indoor and outdoor durability tests

Stack Diffusion Process for Cost- and Energy-Efficient Boron Emitter Formation

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