Schott Solar recently announced that, after six months of collaboration with partners, it has achieved an efficiency of 18% for its copper metallized solar cells. The research project, characterized by the use of polycrystalline silicon wafers as a substrate and a wide-format printed standard backsheet, was conducted in Las Vegas. The aim was to replace the conventional silver contacts on the front panel of solar cells with inexpensive nickel-copper plating. Schott stated that this could reduce the production cost of the cell's front panel by more than half.
The company stated that the biggest challenge was metallization using nickel-copper plating, as researchers had to prevent copper from diffusing into the silicon solar cells. Once inside, copper would reduce electron lifetime and overall cell efficiency. Schott pointed out that to avoid this, the project team developed an electroplated nickel layer as a diffusion barrier and applied appropriate manufacturing techniques to implement this technology on the cells, as well as installing copper contacts.
The company will implement this technology in new cells, installing it in test components to study its long-term stability. Additionally, Schott plans to transfer its developmental success to monocrystalline cells, expecting to increase efficiency to over 19%.
According to another report, Schott Solar stated that their newly developed Quasimono solar silicon wafers have achieved a conversion efficiency of 19.9%, a fact confirmed by Fraunhofer ISE. Quasimono wafers utilize a new technology to manufacture the entire solar silicon wafer, resulting in a higher proportion of monocrystalline silicon. Schott stated that they used a modified traditional VGF process, commonly used in the production of polycrystalline solar wafers. The 19.9% conversion performance is expected to help the SchottPerformMono solar module project advance further in early 2012.
Schott explained that the key feature of Quasimono technology is the partial melting of the seed crystal at the bottom of the crucible. The near-single crystal cultivation utilizes the company's Vertical Gradient Freeze (VGF) technology, and it was noted that pure single-crystal silicon wafers can be produced during ingot formation. Schott acknowledged that Quasimono technology involves the development of new engineering processes and furnace technology, and the research team is further refining this technology.
