New silver paste product promises TOPCon solar cell gains

Silver paste supplier Solamet announced a new product this week, specifically targeting the TOPCon cell technology processed with laser carrier injection, that is well on its way to becoming the industry’s mainstream over the next couple of years.

The paste is targeted at unlocking benefits of laser carrier injection, a post process treatment for TOPCon cells. Laser carrier injection creates more micron-sized silver contact points, improving the contact with the cell surface. However, according to Solamet, current standard silver pastes used in TOPCon cell production don't deliver the efficiency benefits this treatment can bring, and specially designed formulations are needed.

The new paste, PV3NL, designed for laser carrier injection, can be adopted by cell manufacturers without significant changes to their process or machinery. According to Solamet, companies adopting can expect to see at least a 0.2% improvement in absolute efficiency, which it has demonstrated iterations of the TOPCon cell technology.

The company said its latest paste product overcomes a challenge at the interface between the paste and the surface of the cell.

“One of the most significant technical challenges of TOPCon solar cells is the loss of open-circuit voltage and efficiency caused by the recombination issue caused by silver-aluminum pastes contacting p+ surface,” explained Solamet Chief Technology Officer QJ Guo. “Based on in-depth research into the mechanism on metallization induced recombination of the TOPCon p+ surface, the newly developed PV3NL solar paste has been specifically designed.”

Thanks to reduced recombination between the paste and cell and an increased open circuit voltage, the paste can increase the efficiency of TOPCon cells by 0.2% or more, said Guo. The supplier also states that its new product will help to improve module reliability – particularly in glass-backsheet, where the industry has reported some early challenges with TOPCon cells related to corrosion caused by moisture ingress.

The company also says its new paste will be compatible with other process innovations including ultra-thin lines, low paste consumption and low surface concentration diffusion processes for emitter regions.

“We are thrilled that Solamet is once again revolutionizing the photovoltaic industry with groundbreaking technology and product in its new chapter after independent operation,” said Guo. “We remain committed to advancing high-efficiency photovoltaic cell technology through material technology innovations.”

Previously a subsidiary of DuPont, Solamet was acquired in 2021 by Jiangsu Suote Electronic Materials Co., Ltd. and now operates as an independent company.

This article was amended on 01/09 to add additional information on the laser carrier injection treatment.