Potential Gain in Multicrystalline Silicon Solar Cell Efficiency by n-Type Doping

Schindler, Florian; Michl, Bernhard; Kleiber, Andreas; Steinkemper, Heiko; Schön, Jonas; Kwapil, Wolfram; Krenckel, Patricia; Riepe, Stephan; Warta, Wilhelm; Schubert, Martin C.

doi:10.1109/jphotov.2014.2377554

Cited by 30 publications

(17 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…23 Modeling indicates that the >500 ls lifetimes measured after PDG in this 6N's UMG n-type mc-Si are long enough to support high-efficiency solar cells. 6,33 The lifetime trends are also similar to those in a similar study of p-type mc-Si that was gettered at 820 C, 870 C, and 920 C. 10 For both materials, the average lifetimes increased by over an order of magnitude, and the lifetime was longest after PDG at the intermediate temperature.…”

supporting

confidence: 72%

“…One advantage is that some common metal point defects, notably interstitial iron, are less recombination active in n-type than in p-type Si. [1][2][3] It has been shown that phosphorus diffusion gettering (PDG) can increase the lifetime of n-type mc-Si, including in low-lifetime ingot border regions, [4][5][6][7] and that industrially relevant efficiencies are achievable. 8 For p-type mc-Si, simulation of the redistribution of metal impurities during PDG and the resulting lifetime impact has enabled development of PDG processes that improve yield and extract higher performance, especially in border regions and the top of the ingot.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Synchrotron-based investigation of transition-metal getterability in n-type multicrystalline silicon

Morishige

Jensen

Hofstetter

et al. 2016

Applied Physics Letters

View full text Add to dashboard Cite

Solar cells based on n-type multicrystalline silicon (mc-Si) wafers are a promising path to reduce the cost per kWh of photovoltaics; however, the full potential of the material and how to optimally process it are still unknown. Process optimization requires knowledge of the response of the metal-silicide precipitate distribution to processing, which has yet to be directly measured and quantified. To supply this missing piece, we use synchrotron-based micro-X-ray fluorescence (μ-XRF) to quantitatively map >250 metal-rich particles in n-type mc-Si wafers before and after phosphorus diffusion gettering (PDG). We find that 820 °C PDG is sufficient to remove precipitates of fast-diffusing impurities and that 920 °C PDG can eliminate precipitated Fe to below the detection limit of μ-XRF. Thus, the evolution of precipitated metal impurities during PDG is observed to be similar for n- and p-type mc-Si, an observation consistent with calculations of the driving forces for precipitate dissolution and segregation gettering. Measurements show that minority-carrier lifetime increases with increasing precipitate dissolution from 820 °C to 880 °C PDG, and that the lifetime after PDG at 920 °C is between the lifetimes achieved after 820 °C and 880 °C PDG.

show abstract

supporting

confidence: 72%

mentioning

confidence: 99%

Synchrotron-based investigation of transition-metal getterability in n-type multicrystalline silicon

Morishige

Jensen

Hofstetter

et al. 2016

Applied Physics Letters

View full text Add to dashboard Cite

show abstract

“…29 Directional solidification of multicrystalline silicon is relatively low capex, and recent results on ''highperformance'' multicrystalline silicon offer promising routes to high efficiency. 39,44 The capex associated with multicrystalline silicon could be reduced by planned moves to larger ingots 31,45 (further increasing throughput). Czochralski growth could be replaced by multicrystalline silicon, one of the growth techniques mentioned above, or another technique like kyropolis growth, which has demonstrated good material quality with potentially low capex.…”

Section: View Article Onlinementioning

confidence: 99%

Economically sustainable scaling of photovoltaics to meet climate targets

Needleman

Poindexter

Kurchin

et al. 2016

Energy Environ. Sci.

View full text Add to dashboard Cite

aTo meet climate targets, power generation capacity from photovoltaics (PV) in 2030 will have to be much greater than is predicted from either steady state growth using today's manufacturing capacity or industry roadmaps. Analysis of whether current technology can scale, in an economically sustainable way, to sufficient levels to meet these targets has not yet been undertaken, nor have tools to perform this analysis been presented. Here, we use bottom-up cost modeling to predict cumulative capacity as a function of technological and economic variables. We find that today's technology falls short in two ways: profits are too small relative to upfront factory costs to grow manufacturing capacity rapidly enough to meet climate targets, and costs are too high to generate enough demand to meet climate targets. We show that decreasing the capital intensity (capex) of PV manufacturing to increase manufacturing capacity and effectively reducing cost (e.g., through higher efficiency) to increase demand are the most effective and least risky ways to address these barriers to scale. We also assess the effects of variations in demand due to hard-to-predict factors, like public policy, on the necessary reductions in cost. Finally, we review examples of redundant technology pathways for crystalline silicon PV to achieve the necessary innovations in capex, performance, and price. Broader contextTo reduce CO 2 emissions enough over the next fifteen years and avoid the worst effects of climate change will require dramatic increases in the deployment of renewable energy, photovoltaics (PV) in particular. Climate action plans call for 2-10 terawatts (TW) of PV by 2030. Current manufacturing capacity could supply enough for 1 TW of cumulative installations at the end of this period, implying that growth in manufacturing capacity is necessary. Industry roadmaps project up to 2.6 TW but largely fail to assess whether these targets are economically feasible with today's PV module technology. Addressing the question of what technological innovations, if any, would enable rapid manufacturing scale-up requires a conceptual advance in modeling methodology. We address this challenge by coupling three industry-validated models: a bottom-up cost model, an economically sustainable growth-rate calculator, and a constraining demand curve. This approach enables us to determine the sensitivity of PV industry growth to specific technological and economic variables, considering both their effect on the ratio of up-front factory costs to revenue and demand as a function of PV module price. Shifting the demand curve enables us to consider the effects of different policy decisions, like a carbon tax or deployment subsidies.

show abstract

“…An ELBA-analysis, combining injection-dependent lifetime imaging of passivated wafers after different solar cell processing steps in combination with PC1D cell simulations, enables us to predict the efficiency potential of state of the art mc n-type silicon compared with mc p-type silicon for a complete block [5]. This analysis reveals a gain in efficiency potential of 0.7% abs along the whole block height by applying a standard solar cell process on mc n-type (B-diffusion) compared to a standard solar cell process on mc p-type (P-diffusion and firing).…”

Section: A Increased MC Silicon Efficiency Potential By N-type Dopingmentioning

confidence: 99%

“…Quantification of efficiency losses in mc p-type silicon after P-diffusion and firing (left) compared with mc n-type silicon after B-diffusion (center) and P-diffusion (right). Figure adapted from [5].…”

Section: A Increased MC Silicon Efficiency Potential By N-type Dopingmentioning

confidence: 99%

High efficiency multicrystalline silicon solar cells: Potential of n-type doping

Schindler

Schön

Michl

et al. 2015

2015 IEEE 42nd Photovoltaic Specialist Conference (PVSC)

Self Cite

View full text Add to dashboard Cite

By quantifying the role of dopants, impurities and crystal structure, we present guidelines for the fabrication of highly efficient multicrystalline (mc) silicon solar cells. Processed mc n-type wafers feature higher charge carrier diffusion lengths and thus a significantly larger efficiency potential compared with identically produced mc p-type wafers. Still, metal impurities limit the charge carrier lifetime in mc n-type wafers. We identify the main metal impurities in mc n-type silicon and quantify the resulting recombination losses. Attributing the main losses to precipitates and decorated crystal defects, the optimal efficiency potential of mc silicon is exploited by combining n-type highperformance multicrystalline silicon (HPM-Si) with a high efficiency cell concept featuring a full area passivated rear contact (TOPCon). The record cell features an efficiency of 19.6%, which is the highest efficiency reported for an mc n-type silicon solar cell. By reducing series resistance losses and improving the optics of the front surface, efficiencies of 21-22% should be attainable on n-type HPM-Si TOPCon solar cells.

show abstract

Potential Gain in Multicrystalline Silicon Solar Cell Efficiency by n-Type Doping

Cited by 30 publications

References 24 publications

Synchrotron-based investigation of transition-metal getterability in n-type multicrystalline silicon

Synchrotron-based investigation of transition-metal getterability in n-type multicrystalline silicon

Economically sustainable scaling of photovoltaics to meet climate targets

High efficiency multicrystalline silicon solar cells: Potential of n-type doping

Contact Info

Product

Resources

About