Evolutionary PERC+ solar cell efficiency projection towards 24% evaluating shadow-mask-deposited poly-Si fingers below the Ag front contact as next improvement step

Dullweber, Thorsten; Stöhr, Maximilian; Kruse, Christian; Haase, Felix; Rudolph, Martin; Beier, B.; Jäger, Philip; Mertens, Verena; Peibst, Robby; Brendel, Rolf

doi:10.1016/j.solmat.2020.110586

Cited by 41 publications

(27 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The next development step is to replace the Al base contacts with p-type POLO junctions also in either BJ or IBC configuration. Even though the industrial integration of these concepts may be a few years down the road, the building blocks for their realization are currently under development 11 , 28 . Perovskite-Si tandem cells are still in a research state where their economic feasibility is not yet proven.…”

Section: Discussionmentioning

confidence: 99%

Simulation-based roadmap for the integration of poly-silicon on oxide contacts into screen-printed crystalline silicon solar cells

Kruse

Schäfer

Haase

et al. 2021

Sci Rep

Self Cite

View full text Add to dashboard Cite

We present a simulation-based study for identifying promising cell structures, which integrate poly-Si on oxide junctions into industrial crystalline silicon solar cells. The simulations use best-case measured input parameters to determine efficiency potentials. We also discuss the main challenges of industrially processing these structures. We find that structures based on p-type wafers in which the phosphorus diffusion is replaced by an n-type poly-Si on oxide junction (POLO) in combination with the conventional screen-printed and fired Al contacts show a high efficiency potential. The efficiency gains in comparsion to the 23.7% efficiency simulated for the PERC reference case are 1.0% for the POLO BJ (back junction) structure and 1.8% for the POLO IBC (interdigitated back contact) structure. The POLO BJ and the POLO IBC cells can be processed with lean process flows, which are built on major steps of the PERC process such as the screen-printed Al contacts and the $$\text{Al}_\text{2 }\text{O}_\text{3 }/\text{SiN }$$ Al 2 O 3 / SiN passivation. Cell concepts with contacts using poly-Si for both polarities ($$\text{POLO}^2$$ POLO 2 -concepts) show an even higher efficiency gain potential of 1.3% for a $$\text{POLO}^2$$ POLO 2 BJ cell and 2.2% for a $$\text{POLO}^2$$ POLO 2 IBC cell in comparison to PERC. For these structures further research on poly-Si structuring and screen-printing on p-type poly-Si is necessary.

show abstract

Section: Discussionmentioning

confidence: 99%

Simulation-based roadmap for the integration of poly-silicon on oxide contacts into screen-printed crystalline silicon solar cells

Kruse

Schäfer

Haase

et al. 2021

Sci Rep

Self Cite

View full text Add to dashboard Cite

show abstract

“…The PERC technology is dominating the c‐Si photovoltaic solar cell production with 95% market share in 2019 due to its lean process flow and strong evolutionary development 1 . The efficiencies increased by 0.5% per year 2 mainly by improved bulk material quality, 3 by reducing front finger widths 4 and thus shading and contact recombination, as well as by minimizing recombination in the passivated emitter regions 5,6 . However, there are theoretical and practical limits in the PERC cell.…”

Section: Introductionmentioning

confidence: 99%

“…Additionally, there are inherent challenges of the POCl 3 diffusion. Emitter contact recombination can be reduced by further paste improvement and by utilization of selectively doped emitter schemes but still implies J 0e,met values in the range of ~1,400 fA/cm 2 (area‐weighted >28 fA/cm 2 ) 2 . By contrast, the saturation current densities on n‐type poly‐Si on oxide (POLO) passivating contacts can be reduced to <1 fA/cm 2 (~2 fA/cm 2 ) on planar 7–9 (on textured 10,11 ) surfaces.…”

Section: Introductionmentioning

confidence: 99%

Fully screen‐printed silicon solar cells with local Al‐p⁺ and n‐type POLO interdigitated back contacts with a V_OC of 716 mV and an efficiency of 23%

Haase

Min

Hollemann

et al. 2021

Progress in Photovoltaics

Self Cite

View full text Add to dashboard Cite

We demonstrate the fabrication of a fully screen‐printed p‐type silicon solar cell with local hole‐collecting Al‐alloyed (Al‐p+) contacts with a record open circuit voltage of 716 mV. The solar cell is fabricated by using almost the same process equipment as PERC cells. One of the dominant recombination losses in PERC cells is the recombination in the passivated and in the contacted emitter regions that so far limit the open circuit voltage to values below 700 mV. We eliminate these loss channels by substituting the P‐diffused emitter by a passivating n‐type poly‐Silicon on Oxide (nPOLO) contact. We place this contact on the rear side because of its otherwise strong parasitic absorption. The Al‐p+ contacts are also located at the rear side to avoid front‐side shading. This results in a POLO‐IBC cell structure. The efficiency of the best cell so far is 23.0% with a designated area of 4 cm2 fabricated on a M2‐sized wafer. Scanning electron microscopy reveals an Al‐p+ thickness of less than 3.3 μm and only a few 100 nm at the contact ends, which is less than the 5 μm typically for optimized Al‐p+ contacts. A comparison of measured and simulated current‐voltage curves over a variation of the contact fraction extracts a high saturation current density of the Al‐p+ contact of J0‐Al ‐p+ = 2,250 fA cm−2 for the current screen‐print conditions and Al‐paste causing an absolute efficiency loss of 0.5%abs. The recombination at the AlOx/SiNy surface and the shunt resistance limits the cell by 0.6%abs each.

show abstract

“…Ni-Cu metallization is believed to be an alternative method to the current dominant screen-printed metallization in conventional silicon solar cells [20]. Additionally, since the width of Ag fingers is minimized to approximately 35 µm in 2019 from 100 µm in 2010 [21], these fingers will be more susceptible to EM failure.…”

Section: Introductionmentioning

confidence: 99%

Delamination-and Electromigration-Related Failures in Solar Panels—A Review

et al. 2021

View full text Add to dashboard Cite

The reliability of photovoltaic (PV) modules operating under various weather conditions attracts the manufacturer’s concern since several studies reveal a degradation rate higher than 0.8% per year for the silicon-based technology and reached up to 2.76% per year in a harsh climate. The lifetime of the PV modules is decreased because of numerous degradation modes. Electromigration and delamination are two failure modes that play a significant role in PV modules’ output power losses. The correlations of these two phenomena are not sufficiently explained and understood like other failures such as corrosion and potential-induced degradation. Therefore, in this review, we attempt to elaborate on the correlation and the influence of delamination and electromigration on PV module components such as metallization and organic materials to ensure the reliability of the PV modules. Moreover, the effects, causes, and the sites that tend to face these failures, particularly the silicon solar cells, are explained in detail. Elsewhere, the factors of aging vary as the temperature and humidity change from one country to another. Hence, accelerated tests and the standards used to perform the aging test for PV modules have been covered in this review.

show abstract

Evolutionary PERC+ solar cell efficiency projection towards 24% evaluating shadow-mask-deposited poly-Si fingers below the Ag front contact as next improvement step

Cited by 41 publications

References 28 publications

Simulation-based roadmap for the integration of poly-silicon on oxide contacts into screen-printed crystalline silicon solar cells

Simulation-based roadmap for the integration of poly-silicon on oxide contacts into screen-printed crystalline silicon solar cells

Fully screen‐printed silicon solar cells with local Al‐p⁺ and n‐type POLO interdigitated back contacts with a V_OC of 716 mV and an efficiency of 23%

Delamination-and Electromigration-Related Failures in Solar Panels—A Review

Contact Info

Product

Resources

About

Evolutionary PERC+ solar cell efficiency projection towards 24% evaluating shadow-mask-deposited poly-Si fingers below the Ag front contact as next improvement step

Cited by 41 publications

References 28 publications

Simulation-based roadmap for the integration of poly-silicon on oxide contacts into screen-printed crystalline silicon solar cells

Simulation-based roadmap for the integration of poly-silicon on oxide contacts into screen-printed crystalline silicon solar cells

Fully screen‐printed silicon solar cells with local Al‐p+ and n‐type POLO interdigitated back contacts with a VOC of 716 mV and an efficiency of 23%

Delamination-and Electromigration-Related Failures in Solar Panels—A Review

Contact Info

Product

Resources

About

Fully screen‐printed silicon solar cells with local Al‐p⁺ and n‐type POLO interdigitated back contacts with a V_OC of 716 mV and an efficiency of 23%