​3.1.2 Demonstrations of Ultra-High Efficiency, Stable Perovskite Tandems

• Demonstrate progress in perovskite-based tandems with various bottom cells using monolithic integration and/or mechanical stacking targeting ultra-high efficiency with each technology investigated.

• Develop integration strategies for mechanically stacked perovskite tandems, to reduce optical losses and maximise optical coupling.

• Develop cell designs for monolithically integrated tandems, considering temperature requirements and texturing or surface roughness of bottom cells.

• Investigate device modelling to identify key optical and electrical losses of current tandems and to develop new cell designs for future tandems including longer term prospects for triple junction tandems