Innovative technologies will drive PV metallization costs down

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In a new report, titled Key Issues and Innovations in Photovoltaic Metallization, Lux Research wrote that innovative new technologies, including copper metallization, nickel phosphide and non-contact printing techniques, which can replace silver, could reduce costs by up to 50 percent.

The company said that silver costs have risen six-fold in the last 10 years, to hit around US$30 an ounce, meaning companies have had to search for other ideas and reduce their silver usage. "Applied Materials’ double-printing tool reduces silver usage by 30 percent relative to conventional screen printing and improves absolute cell efficiencies by 0.3 percent to 0.5 percent, offering the nearest term bang for the buck. But the technology roadmap won’t stop there," said Lux Research.

The "logical" silver replacement, it continued, is copper, due to its abundance and already-established use in the semiconductor industry. Underpinning this, Imec’s PV business development director, Philip Pieters told pv magazine last December that the work on copper metallization for silicon solar cells has been one of the "key activities" of Imec and Kaneka’s Si-PV research and development program.

He added that the use of copper in commercial cell production could come sooner than many think. Just recently, the two parties achieved achieved an efficiency of 22.68 percent on a six inch semi-square heterojunction silicon solar cell using an electroplated copper contact grid.

However, Lux Research said that copper pastes "need further development because they lag in cell performance and long-term durability; Napra and Japan’s National Institute of Advanced Industrial Science and Technology (AIST) are blazing the trail but others will enter to open a path to practical copper metallization for both x-Si and CIGS PV."

Meanwhile, it added that Nickel phosphide (Ni2P) will be the widely adopted back contact for CdTe metallization. "Ni2P has shown durability, anneals at high temperature and does not require expensive materials. It can slightly trim costs and significantly improve yields," it said.

Lux Research went on to say that these metallization innovations also have the potential to improve process yields for crystalline silicon (c-Si), copper indium gallium (di)selenide (CIGS) and cadmium telluride (CdTe) technologies.

"Tomorrow’s PV winners will be those companies that can reduce their production costs in $/W and maintain sustainable profit margins. Metallization is a key materials-driven driver for higher efficiencies, reduced production costs and improved yields," stated Fatima Toor, Lux Research analyst and lead author of the report.