Metallization of solar cells is a process by which metal electrodes are laid down on a non-metallic object to collect the electricity generated by the sunlight. But it is a costly process, due in large part to the soaring cost of the silver that is normally used. However, according to a new report by Lux Research, emerging technologies, like copper metallization, nickel phosphude, and non-contact printing techniques, are likely to reduce the costs of metallization.
Innovation in the field has the potential to bring costs down by up to 50 percent and improve the yields for the three major technology categories — crystalline silicon (x-Si), copper indium gallium (di)selenide (CIGS), and cadmium telluride (CdTe).
“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,” said Fatima Toor, Lux Research Analyst and the lead author of the report, “Key Issues and Innovations in Photovoltaic Metallization.”
Lux Research analysts studied emerging innovations in metallization to determine their impact on solar cell production. Among their findings:
- Drive to reduce silver use is inevitable. Over the past decade, silver prices have risen six-fold to about $30/ounce, necessitating lower usage and other work-arounds. Applied Materials’ double-printing tool reduces silver usage by 30% relative to conventional screen printing and improves absolute cell efficiencies by 0.3% to 0.5%, offering the nearest term bang for the buck. But the technology roadmap won’t stop there.
- Copper pastes are the logical metallization winner. Copper is the leading contender to displace silver, given its abundance and established use in the semiconductor electronics industry. But 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.
- 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.