The company has said two types of cells containing Ag-screen printed contacts and plated copper (Cu) contacts will be shown. Efficiencies of cells with screen-printed contacts were up to 19.1 percent, it said, whereas 19.4 percent was obtained with Cu-plated contacts.
It explained these efficiencies were obtained due to several factors, including a combination of improved texturization and optimized firing conditions. The results were achieved on large-area cells (148cm2) with 170µm thickness, it added, thus proving the industrial viability of the process.
imecs record efficiency silicon solar cells feature rear-side passivation, laser ablation and, local aluminum back-side field and screen printed contacts or Cu-plated contacts on advanced emitter schemes.??
The fact that such efficiencies can be obtained by metallization schemes based on screen printed Ag contacts enables compatibility with present industrial metallization practice in the solar cell industry, commented Dr. Joachim John, team manager industrial solar cells at imec.
The Cu-based front-side metallization is a step towards higher sustainability and lower cost, substituting Ag with Cu in future industrial production of crystalline silicon solar cells. ??
Dr. Jef Poortmans, director imec energy/solar program added: High efficiency, low cost, and sustainability are the main drivers in imecs 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 percent 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 imecs silicon solar cell industrial affiliation program (IIAP), a multi-partner 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.