Filament stretching during parallel dispensing – A way to reduce silver consumption in SHJ metallization

Gensowski, Katharina; Much, Maximilian; Palme, Melanie; Jimenez, Ana; Bujnoch, Elisabeth; Muramatsu, Keiichi; Tepner, Sebastian; Clement, Florian

doi:10.1016/j.solmat.2022.111871

Cited by 9 publications

(27 citation statements)

References 29 publications

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“…That means that the shear viscosity η s decreases when the shear rate γ : increases. The rheological properties of the reference paste Ref have been investigated in the literature, [23,25] so-called paste A. Such shear-thinning behavior is well known for printing pastes applied for solar cell metallization.…”

Section: Shear Rheological Characterization Of Pastesmentioning

confidence: 99%

“…Consequently, the parallel dispensing process with highly filled suspension is a complex and challenging printing technique, however, it shows great potential for solar cell metallization like a more effective silver usage due to approximately constant electrode height along the entire electrode length. [23] The choice of paste components and formulations drastically impacts on the dispensing process, the printing result, and its performance in the application. Especially, the rheological behavior and homogeneity of the paste while processing exhibit crucial roles.…”

Section: Introductionmentioning

confidence: 99%

“…Complexity of dispensing processes. This overview illustrates different influencing factors on printed electrodes and their functionality [9,10,14,16,64,65] classified into six categories -I) printing pastes and their compositions, [13,23,[25][26][27]33,34,37,49,50,[66][67][68][69][70][71][72][73][74][75][76] II) substrates, III) print heads, [18][19][20][21][22][23]77] IV) nozzles, [15,18] V) printing machines, and VI) process parameters. [23,25,78] The list of influencing factors is created based on some articles and the authors' hands-on laboratory experiences and may be incomplete.…”

Section: Introductionmentioning

confidence: 99%

“…This effect shows great potential to enable narrower electrodes due to paste properties without decreasing the nozzle diameter as smaller nozzles may have increased risks for process instabilities and nozzle clogging. [23,25] Figure 2 depicts an overview of the parallel dispensing process and the effect of filament stretching. Low-temperature curing pastes may exhibit the effect of filament stretching during microextrusion, showing a process velocity range of category II.…”

Section: Introductionmentioning

confidence: 99%

“…The classification of different dispensed electrode shapes are illustrated in the ref. [23,25]. The phenomenon of filament stretching is not restricted to silver-containing low-temperature curing pastes.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Paste Development for an Optimized Filament Stretching Effect during Parallel Dispensing on Transparent Conductive Oxide Layers for Solar Cell Metallization

Gensowski,

Palme,

Langhof

et al. 2023

Adv Eng Mater

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The availability of silver as an electrically conductive filler material in printing pastes for solar cell metallization is becoming a more crucial issue for multiterawatt‐scale production due to its global constraints. Therefore, the silver consumption for solar cell production needs to be reduced drastically by substituting silver with alternative conductive filler materials or utilizing process‐specific phenomena. The phenomenon of filament stretching during microextrusion allows significantly lower paste laydowns. The magnitude of filament stretching is paste‐dependent and therefore further knowledge of the pastes’ impact to the filament stretching is required. This study presents nine low‐temperature curing pastes differing in the particle system and binder resin. The rheological and thermal behavior of these suspensions are investigated and printing tests onto silicon heterojunction (SHJ) precursors are carried out. Additionally, scanning electron microscopy (SEM)‐based microstructure analyses of printed electrodes are performed. Based on these experimental results, the impact of paste compositions regarding the paste behavior during microextrusion and the SHJ solar cell performances are analyzed. The developed paste formulations exhibit a strong filament stretching, leading to a reduced silver laydown of down to ΔmAg = −60%rel. and an absolute efficiency gain of up to Δη = +0.75%abs. due to less shading losses.

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Section: Shear Rheological Characterization Of Pastesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Paste Development for an Optimized Filament Stretching Effect during Parallel Dispensing on Transparent Conductive Oxide Layers for Solar Cell Metallization

Gensowski,

Palme,

Langhof

et al. 2023

Adv Eng Mater

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High‐Throughput Indirect Gravure Printing Applied to Low‐Temperature Metallization of Silicon‐Based High‐Efficiency Solar Cells

Schube,

Klawitter,

Linse

et al. 2024

Energy Tech

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Herein, this work is dedicated to a both exotic and promising printing technique in silicon (Si) photovoltaics (PV). Indirect gravure printing is investigated as a metallization technique focusing on low‐temperature applications, such as Si heterojunction (SHJ) and perovskite Si tandem solar cells. One advantage of this rotary printing technique is that its components are very durable. From graphical industry, it is known that gravure cylinders show almost no wearing during multiple printing. Additionally, rotary printing techniques offer great throughput. Therefore, indirect gravure printing can reduce costs significantly in PV production. In this work, short process cycle times of 0.9 s cell−1 for industrial wafers (edge length of 156.75 mm) are demonstrated. Using an appropriate production platform even enables cycle times of down to 0.5 s cell−1. Busbarless SHJ half cells with non‐optimized gravure‐printed front grids reach a mean photoconversion efficiency that is (1.7 ± 0.5) %abs lower compared to screen‐printed reference samples, however, cycle time is reduced. The metal contacts exhibit a mean shading width of (65 ± 16) μm and an average height of (5 ± 1) μm. Applied to SHJ solar cells’ rear, such metallization can replace screen‐printed contacts with 0.1%abs efficiency loss only, as device simulations reveal.

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Curing conditions for low‐resistivity contacts on transparent conductive oxide layers for different solar cell applications

Gensowski,

Freund,

Much

et al. 2023

Progress in Photovoltaics

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The Cu (ln1‐xGax)Se2 (CIGS) solar cell technology is a potentially high‐efficient approach with unique properties compared with silicon photovoltaic, like flexible lightweight substrates and different colored designs. So far, the full potential of the transparent conductive oxide layers has not been exploited yet as no front contacts are applied, resulting in significant losses from the cell‐to‐module level. In this study, Ag front contacts are applied by parallel dispensing onto indium tin oxide layers of silicon heterojunction substrates and CIGS substrates. Subsequently, a thermally curing process is carried out to form the conductive contacts. The curing conditions are varied between 200°C ≥ Tc ≥ 100°C combined with 20 min ≥ tc ≥ 1.5 min. The study aims to determine the curing parameters enabling low‐resistivity contacts by using low‐temperature curing Ag paste and ultralow‐temperature curing Ag paste. The lateral electrode resistance and the contact resistivity of printed electrodes are measured. The results of simultaneous thermogravimetry‐differential scanning calorimetry (pastes) and microstructure analysis of printed electrodes are used to explain the electrical parameters of the printed electrodes. In general, higher curing temperatures and longer curing durations encourage the sintering and densification process of the applied electrodes resulting in low‐resistivity contacts. Contact resistivities below ρc,TLM < 5 mΩ·cm2 and lateral electrode resistance of Rlateral ≥ 17 Ω m−1 are obtained for different paste systems. However, optimal curing conditions of low‐temperature curing pastes can cause thermal damage to the CIGS device. Therefore, ultralow‐temperature curing pastes seem to be promising candidates for front contact metallization of CIGS substrates.

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Filament stretching during parallel dispensing – A way to reduce silver consumption in SHJ metallization

Cited by 9 publications

References 29 publications

Paste Development for an Optimized Filament Stretching Effect during Parallel Dispensing on Transparent Conductive Oxide Layers for Solar Cell Metallization

Paste Development for an Optimized Filament Stretching Effect during Parallel Dispensing on Transparent Conductive Oxide Layers for Solar Cell Metallization

High‐Throughput Indirect Gravure Printing Applied to Low‐Temperature Metallization of Silicon‐Based High‐Efficiency Solar Cells

Curing conditions for low‐resistivity contacts on transparent conductive oxide layers for different solar cell applications

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