A simple criterion for predicting multicrystalline Si solar cell performance from lifetime images of wafers prior to cell production

Wagner, Hannes; Müller, M.; Fischer, Gerd; Altermatt, P.P.

doi:10.1063/1.4817272

Cited by 24 publications

(11 citation statements)

References 18 publications

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“…2, and the square-root-weighted harmonic mean Lifetime for each sample, calculated as ~ = li; ~. wh.ich is proportional to the vTov n y'T1 harmonic mean minority-carrier diffusion length and a strong predictor of cell performance [26]- [28], is reported in Table I.…”

Section: A Lifetime Impact Of One-and Two-step High-temperature Gettmentioning

confidence: 99%

Investigation of Lifetime-Limiting Defects After High-Temperature Phosphorus Diffusion in High-Iron-Content Multicrystalline Silicon

Fenning

Zuschlag

Hofstetter

et al. 2014

IEEE J. Photovoltaics

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Abstract-Phosphorus diffusion gettering of multicrystalline silicon solar cell materials generally fails to produce material with minority-carrier lifetimes that approach that of gettered monocrystalline wafers, due largely to higher levels of contamination with metal impurities and a higher density of structural defects. Higher gettering temperatures should speed the dissolution of precipitated metals by increasing their diffusivity and solubility in the bulk, potentially allowing for improved gettering. In this paper, we investigate the impact of gettering at higher temperatures on low-purity multicrystalline samples. To analyze the gettering response, we measure the spatially resolved lifetime and interstitial iron concentration by microwave photoconductance decay and photoluminescence imaging, and the structural defect density by Sopori etching and large-area automated quantification. Higher temperature phosphorus diffusion gettering is seen to improve metal-limited multicrystalline materials dramatically, especially in areas of low etch pit density. In areas of high as-grown dislocation density in the multicrystalline materials, it appears that higher temperature phosphorus diffusion gettering reduces the etch pit density, but leaves higher local concentrations of interstitial iron, which degrade lifetime.

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Section: A Lifetime Impact Of One-and Two-step High-temperature Gettmentioning

confidence: 99%

Investigation of Lifetime-Limiting Defects After High-Temperature Phosphorus Diffusion in High-Iron-Content Multicrystalline Silicon

Fenning

Zuschlag

Hofstetter

et al. 2014

IEEE J. Photovoltaics

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“…[ 77 ] The spatially resolved minority carrier lifetime after gettering was evaluated for samples from adjacent ingot heights and thus sharing the same crystal defect structure by microwave photoconductive decay with iodine ethanol surface passivation. The resulting harmonic root mean minority carrier lifetime, τ av , a strong predictor of cell effi ciency, [80][81][82] and calculated as…”

Section: Process Optimization Resultsmentioning

confidence: 99%

Darwin at High Temperature: Advancing Solar Cell Material Design Using Defect Kinetics Simulations and Evolutionary Optimization

Fenning

Hofstetter²,

Morishige³

et al. 2014

Advanced Energy Materials

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Material defects govern the performance of a wide range of energy conversion and storage devices, including photovoltaics, thermoelectrics, and batteries. The success of large‐scale, cost‐effective manufacturing hinges upon rigorous material optimization to mitigate deleterious defects. Material processing simulations have the potential to accelerate novel energy technology development by modeling defect‐evolution thermodynamics and kinetics during processing of raw materials into devices. Here, a predictive process optimization framework is presented for rapid material and process development. A solar cell simulation tool that models defect kinetics during processing is coupled with a genetic algorithm to optimize processing conditions in silico. Experimental samples processed according to conditions suggested by the optimization show significant improvements in material performance, indicated by minority carrier lifetime gains, and confirm the simulated directions for process improvement. This material optimization framework demonstrates the potential for process simulation to leverage fundamental defect characterization and high‐throughput computing to accelerate the pace of learning in materials processing for energy applications.

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“…Shockley–Read–Hall (SRH) model with two defect levels is used to account for the injection dependent minority carrier lifetime. Due to the spatial inhomogeneous lifetime of mc‐Si, there are several methods that can be applied for providing input to numerical simulations . To account for the spatial variation between different grains, the lifetime on a representative region of a sister wafer to the cell is measured with the Sinton lifetime tester .…”

Section: Simulationmentioning

confidence: 99%

21.63% industrial screen-printed multicrystalline Si solar cell

Zheng¹,

Jing²,

Sun³

et al. 2017

Phys. Status Solidi RRL

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In this paper, we demonstrate industrially feasible large‐area solar cells achieving energy conversion efficiency up to 21.63% on p‐type boron doped multicrystalline Si wafers. Advanced light trapping, passivation and hydrogenation technology are used to achieve excellent light absorption with very low surface recombination velocity. The bulk lifetime of the multi‐crystalline Si wafers used for the fabrication exceeds 500 μs after optimized gettering and hydrogenation processes. The high bulk lifetime and excellent surface passivation enable Voc to exceed 670 mV. The metallization process is carried out by screen printing and firing in a conventional belt furnace. Detailed performance parameters and quantum efficiency of the cells will be illustrated in the paper. In addition, free energy loss analysis and cell simulation are also performed using the control parameters measured during cell fabrication processes.

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A simple criterion for predicting multicrystalline Si solar cell performance from lifetime images of wafers prior to cell production

Cited by 24 publications

References 18 publications

Investigation of Lifetime-Limiting Defects After High-Temperature Phosphorus Diffusion in High-Iron-Content Multicrystalline Silicon

Investigation of Lifetime-Limiting Defects After High-Temperature Phosphorus Diffusion in High-Iron-Content Multicrystalline Silicon

Darwin at High Temperature: Advancing Solar Cell Material Design Using Defect Kinetics Simulations and Evolutionary Optimization

21.63% industrial screen-printed multicrystalline Si solar cell

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