Oxford PV say they have some that work ok being put into commercial use on a small scale - https://www.oxfordpv.com/news/20-more-powerful-tandem-solar-panels-en

Oxford PV say they have some that work ok being put into commercial use on a small scale - https://www.oxfordpv.com/news/20-more-powerful-tandem-solar-panels-enter-commercial-use-first-time-us https://www.oxfordpv.com/news/20-more-powerful-tandem-solar-...