To people joining this thread later asking where a commercial product of this is, or pointing out that 10% solar efficiency is way below other existing products, you’re missing the point.
This is basic research to prove one single aspect of solar panel construction. That question apparently was: “We currently know that PET backsheets work for solar panels, but can we use a different material which may have less CO2 impact and still produce a working solar panel?” The answer being “yes”. That is a big step that other people doing other research and product development can build on. It may be years (or never!) that a product comes to market with sisal fiber backsheets, but the answers from the work done here are integrated into the body of knowledge that will produce the next improvement in solar panels.