ECN, part of TNO, and its partners in Solliance are working to combine perovskite thin film technology with crystalline silicon technology to create photovoltaic tandem modules. ECN also develops bifacial silicon technology. By combining both approaches, the research partnership has now obtained a 30.2% equivalent efficiency for a bifacial tandem solar device.   This is an important breakthrough because it combines a bi-facial design with state-of-the-art tandem technology to produce a 30+% equi...