Imec reports large area silicon solar cells with high efficiency
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IMEC has unveiled several large area silicon solar cells with a conversion efficiency above 19%. The innovations were displayed at the 25th European Photovoltaic Solar Energy Conference in Valencia.
The nanoelectronics research specialist says it has achieved efficiencies of cells with screenprinted contacts up to 19.1% whereas 19.4% was obtained with Cu-plated contacts. According to imec, these efficiencies were obtained through a combination of improved texturisation and optimised firing conditions.
The results were achieved on large area cells (148cm2) with 170µm thickness, proving the industrial viability of the process.
The silicon solar cells feature rear side passivation, laser ablation and, local aluminum back side field and screenprinted contacts or Cu-plated contacts on advanced emitter schemes.
"The fact that such efficiencies can be obtained by metallisation schemes based on screenprinted Ag contacts enables compatibility with present industrial metallisation practice in the solar cell industry," said Dr Joachim John, team manager, industrial solar cells at imec. "The Cu-based front side metallisation is a step towards higher sustainability and lower cost, substituting Ag with Cu in future industrial production of crystalline silicon solar cells. These exciting results were obtained in the new solar cell process facilities recently set up in imec."
Dr Jef Poortmans, director, imec energy/solar program, added: "High efficiency, low cost, and sustainability are the main drivers in imec's research on crystalline silicon solar cells, eventually targeting cells that are only 40µm thick with efficiencies above 20. We expect further improvements towards efficiencies of up to 20% for large area silicon solar cells. This achievement is a major step forward towards industrial manufacturing of sustainable, low cost, thin silicon solar cells with high efficiency."
The results were achieved within imec's silicon solar cell industrial affiliation program, a multipartner R&D program that explores and develops advanced process technologies aiming a sharp reduction in silicon use, whilst increasing cell efficiency and hence further lowering substantially the cost per Watt peak.
