Silicon thin film triple junction cell boost efficiencies to 14.8% for Mitsubishi

A triple-junction thin-film silicon cell structure that utilizes the majority of the solar spectrum is in development phase at Mitsubishi Electric. A 5mm x 5mm cell is claimed to have produced conversion efficiencies of 14.8% in the lab. High-quality film-deposition processing of each layer was required. Mitsubishi said that first layer absorbs short wavelengths and the third layer absorbs long wavelengths. Texture fabrication was also applied to transparent electrodes for optimal confinement of light.

Mitsubishi said it intends to continue its R&D of the triple-junction cell with the aim to raise conversion efficiencies further. Work will focus on improving cell structure and materials as well as processing conditions.