DuPont has sued SunEdison for patent infringement, accusing the solar array developer of contracting with suppliers and manufacturers that infringed on proprietary technology.

The US chemical giant said SunEdison and its affiliate NVT sourced and used solar cells and modules from cell manufacturer Neo Solar Power and Flextronics, a contract manufacturer. It noted also that SunEdison is using metallization paste from Samsung SDI that falls under its patent for "Tellurium" paste.

"DuPont will enforce its patent rights to protect our substantial investment in innovation to improve solar energy efficiency," said Peter Brenner, the company's photovoltaic business manager, adding that "installers and module makers like SunEdison are responsible for ensuring that their products do not use infringing cells or pastes."

SunEdison and SunEdison Semiconductor are longtime partners of Samsung.

In 2012, DuPont sued Germany's Heraeus Materials and its client, SolarWorld, but settled out of court in October of that year.