Hitoshi Sai

Hidenori Mizuno¹, 

Hitoshi Sai², 

Koji Matsubara², 

Hidetaka Takato¹, 

Michio Kondo¹ 

¹Renewable Energy Research Center, Fukushima Renewable Energy Institute, National Institute of Advanced Industrial Science and Technology, Koriyama, Fukushima, Japan, 

²Research Center for Photovoltaic Technologies, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, Japan