This week in our Talking with Start-Ups series we spoke to Scott Graybeal, CEO at perovskite start up Caelux. This company is chasing a $15 million Series A round, and has only recently dropped out of stealth. It came out of work on crystal silicon at Caltech back in 2014, and 5 years ago switched to Perovskite full time. Its approach to Perovskite is original, in that it adds a semi-transparent layer of perovskite onto glass which has an efficiency rating of 17.5%, and then sends that to partners who make conventional silicon solar panels to use the glass on their modules. When the glass is mounted on a silicon cell that harvests 22% of the energy that hits it,…