A Chinese research team has investigated impurity and defect levels in solar cells based on mono cast waffles and has discovered that approximately 30% of the devices show an “excessive” reduction of the efficiency of power conversion. The scientists concluded that Cast Monocrystallijn Silicon will be unlikely to conquer a meaningful market share in the near future.
Researchers at Zhejiang University in China have built the impact of impurities and defects on the performance of solar cells with mono -cast silicon (CMI) Waffles and have discovered that only about 70% of the cells that are produced with this material can be equal that is achieved with conventional Czochralski waffles.
Mono-gains and waffles for PV applications are made with sown cast silicon, which is also known as Cast-Mono or quasi-mono crystalline silicon. The Cast Mono process facilitates the production of “mono -like” wafer materials using a modified multicistalline oven, while avoiding expensive investments in Ingot -Trekmachines. Cast-Mono waffles are less susceptible to recombination caused by drilling oxyte defects and have the advantage of slightly induced demolition. However, their commercial adulthood is far from achieved due to the lack of suitable processes later in the production line.
“Our research offers an application-oriented analysis of how impurity defects in cast monocrystalline silicon materials influence the performance of solar cells,” said the main author of the research, Shuai Yuan, said PV -Magazine. “Although previous studies have mainly emphasized the optimum performance of Cast Monokrystalline Materials, our work is investigating the problem from the perspective of the minimum production cycle unit – a complete crystal ingot.”
“We have identified dislocation clusters and metal contamination as the two primary factors that influence efficiency,” he said. ‘Both factors contribute to efficiency cake in solar cells. Dislocation clusters come at the top of the crystal and are a much greater risk for cell performance than metal contamination from melting pot diffusion. “
In the study “Analysis and impact of impurity defects on the efficiency and stability of cast -produced cast monocrystalline silicon waffles and solar cells“Published in Solar energy materials and solar cellsThe research team explained that persistent defects with high density remain the most important obstacle for this WAFER technology to become competitive in the PV industry.
The academics carried out a series of experiments on perc sun cells based on Metal Wrap-Through (MWT) design using a commercial Czochralski Silicon (CZ-Si) cell production line. They used photoluminescence (PL) measurements in areas of waffles identified by PL image formation as contained very recombination-active defects. In addition, they used electroluminescence (EL) to assess the performance of solar cells.
“We have shown that although about 70% of the cast monocrystalline silicon waffles perform similar to Czochralski-grown Monokrystallijn Silicon, the remaining 30% excessive tail,” said Yuan. “Metaliffusie and defect propagation at the top remain inherent challenges in the casting method that still have to be resolved. Moreover, our findings show that significant low efficient factors in the mass production can easily be identified by simple comparisons of efficiency data.
“Currently, leading manufacturer-belonging in China-Die are shifting the focus to advanced cell technologies such as N-Type Topcon and heterojunction cells, which demand exceptionally high Silicon wafer lifetime,” concluded Yuan. “Significant R&D efforts are also aimed at pure perovskiet and tandem cells. Until these persistent problems are tackled, it is unlikely that cast monocrystalline silicon will determine a meaningful market share, despite the lower crystal growth costs.”
In 2022, another group developed a production technique at Zhejiang University to produce high-quality mono-cast silicon (CMI) ingrots with a stable monocrystalline ratio for applications for solar cells.
In 2019, Canadian Solar said that it had achieved 22.8% efficiency for its P-type multicrystalline P5 sun cell, based on Mono Cast technology. Only a few months earlier, rival GCL Systems Integration Cast Mono Tech modules revealed with 18.9% efficiency.
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