A miniature solar device for overall water splitting consisting of series-connected spherical silicon solar cells

Yosuke Kageshima, Tatsuya Shinagawa, Takaaki Kuwata, Josuke Nakata, Tsutomu Minegishi, Kazuhiro Takanabe, Kazunari Domen

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


A novel “photovoltaics (PV) + electrolyzer” concept is presented using a simple, small, and completely stand-alone non-biased device for solar-driven overall water splitting. Three or four spherical-shaped p-n junction silicon balls were successfully connected in series, named “SPHELAR.” SPHELAR possessed small projected areas of 0.20 (3PVs) and 0.26 cm2 (4PVs) and exhibited working voltages sufficient for water electrolysis. Impacts of the configuration on the PV module performance were carefully analyzed, revealing that a drastic increase in the photocurrent (≈20%) was attained by the effective utilization of a reflective sheet. Separate investigations on the electrocatalyst performance showed that non-noble metal based materials with reasonably small sizes (
Original languageEnglish (US)
JournalScientific Reports
Issue number1
StatePublished - Apr 18 2016

Cite this