TOPCon cells and heterojunction (HJT/HIT) cells are traditional crystalline silicon cells and are second-generation photovoltaic cell technologies. Perovskite cells are representatives of the third-generation non-silicon thin film cells.
Perovskite/crystalline silicon tandem cells are a combination of these two technical routes. They are double-junction solar cells formed by superimposing perovskite solar cells and traditional crystalline silicon solar cells. To put it simply, , refers to connecting perovskite cells in series on the surface of crystalline silicon cells.
At present, pure perovskite cells have not yet completely overcome the problem of excessive efficiency decay, and perovskite/crystalline silicon stacked cells are expected to become the best industrialized technology.
From a performance perspective, perovskite/crystalline silicon stacked cells broaden the absorption spectrum through the advantages of the combination and obtain higher photoelectric conversion efficiency than pure crystalline silicon cells or perovskite cells. Theoretically The conversion efficiency can exceed 30.
In terms of theoretical limit conversion efficiency, the limit efficiencies of HJT, TOPCon, and perovskite single-layer cells are 27.5, 28.7, and 31 respectively.
It is worth noting that perovskite/crystalline silicon stacked cells are expected to create more possibilities for heterojunction cells represented by HJT. This is because both heterojunction battery technology and perovskite battery technology are low-temperature processes. The production equipment of the two technologies is relatively compatible. Moreover, heterojunction batteries generate electricity on both sides and have thin film processes.
So perovskite technology is easier to stack on the basis of heterojunction cells. TOPcon battery technology is a high-temperature process and does not have a transparent conductive film itself. It is naturally more difficult to superimpose perovskite technology than heterojunction technology.