Perovskite/silicon tandem cell technologies are probably the future generation of photovoltaics. Made by stacking a top cell of perovskite material on top of a bottom cell of silicon, these tandems promise a higher conversion efficiency of the solar energy received, higher than the current standard of single-junction silicon cells, at a low additional cost.
Today, environmental impact assessment and life cycle analysis of technologies must guide research efforts towards cell and panel designs with minimal environmental impact. Yet, it is still very difficult to orientate this immature tandem technology, for which record efficiencies of around 30% have only been demonstrated on surfaces of the range of 1 cm², and which generally uses laboratory processes for the layer deposition. The lack of a reference framework integrating technological progress, resulting from the low TRL of tandem technology, combined with the non-existence of a life cycle inventory for the materials constituting the top cell layers, makes the environmental analysis particularly complex. This is due to the large number of materials explored for the making of the different new layers and the fact that there is no fixed process for their implementation.
The high variability of the data and results of the state of the art, amplified by a still too weak expertise of the community on environmental aspects, is not compatible with the requirements of life cycle assessment (LCA), which demands a low level of uncertainty and a high quality of data.