Imec's perovskite/silicon solar module reaches 23.9% efficiency

Belgian research centre Imec has announced that it has boosted the performance of its its 4 cm2 perovskite/silicon tandem photovoltaic module to a power conversion efficiency of 23.9%. According to Imec, this is the first time that a module-on-cell stack structure has outperformed a standalone silicon solar cell.

'Two innovations are key to this achievement,' said group leader for thin-film photovoltaics at imec and perovskite PV program manager at Solliance. 'First, a different perovskite material (CsFAPbIBr) was used, largely improving the stability and conversion efficiency of the 4 cm 2 semi-transparent perovskite module to 15.3%. Second, the architecture of the stack was optimized for minimal optical losses by adding an anti-reflection texture on top of the module and a refractive index matching liquid between the perovskite module and the Si solar cell.'

'Having matched areas of this (4 cm ²) size makes the fabrication technology more attractive to the solar cell industry,' commented Aernouts. 'For reference, we have also fabricated a stack of a small perovskite cell (0.13 cm 2) on top of an IBC c-Si cell (4 cm 2). In this configuration, the power conversion efficiency of the small semi-transparent perovskite cell is 16.7%, outperforming the larger 4cm2 perovskite module due to better perovskite layer properties. Although less attractive from an industrial point of view, the overall power conversion efficiency of this cell-on-cell stack is as high as 25.3%.'