Japan's push into 'deep tech' innovation
Imagine if you could put an ultra-thin, transparent solar sheet on your window to generate energy, not just from sunlight but also artificial lights from inside your room?
Seen as the most promising next-generation solar cell, this technology, called perovskite, is exactly what Japanese start-up Enecoat Technologies is trying to develop.
Presented by Mariko Oi for BBC News