'Workhorse' of photovoltaics integrated with perovskite in tandem for the very first time

• Tandem cells made from silicon and perovskite are able to convert the wide power range of sunlight into electrical energy extra successfully than the respective single cells.

Now, for the first time, 2 groups from HZB and also ISFH Hameln have actually succeeded in incorporating a perovskite leading cell with a so-called PERC/POLO silicon cell to create a tandem gadget. This is a crucial accomplishment, considering that PERC silicon cells on p-type silicon are the "workhorse" of photovoltaics, with a market share of about 50% of all solar cells generated worldwide. They are mostly maximized, long-lasting stable and also temperature level stable. For that reason, it is specifically intriguing for the commercialisation of a perovskite-silicon tandem technology to create a "perovskite tandem upgrade" for PERC cells. The participation occurred within the structure of the joint project P3T, which is moneyed by the Federal Ministry of Economics and also worked with by HZB

The group at ISFH made use of an industry-compatible PERC process for the backside contact of the silicon bottom cells. On the front side of the wafer, another industrialisable modern technology was used, the so-called POLO call, which was adapted below for the small-area proof of principle cells.

Perovskite proficiency at HZB.

The following process actions took place at HZB: A tin-doped indium oxide recombination layer was used as a contact between both subcells. On top of this, a perovskite cell was processed with a layer sequence comparable to that in the existing globe record tandem cell on n-type silicon heterojunction cells, made by HZB. The initial perovskite PERC/POLO tandem cells created in this way attain an efficiency of 21.3% on an active cell location of regarding 1 centimeters ². This efficiency is thus still below the efficiency of optimized PERC cells in this feasibility research. "Nevertheless, initial speculative results as well as optical simulations indicate that we can considerably improve the performance through procedure as well as layer optimisation," clarifies Dr. Lars Korte, the equivalent author of the study.

PCE estimated at 29.5 %

The experts approximate the Power Conversion Efficiency (PCE) of these perovskite/silicon tandem solar cells with PERC-like sub-cell technology at 29.5 %. The next actions for further efficiency increases are currently clear: Dr. Silvia Mariotti from the HZB team had determined the insurance coverage of the silicon surface area by the perovskite as potential for enhancement. "For this function, one could adjust the surface area of the silicon wafers and also hence quickly boost the efficiency to about 25%," claims Mariotti. This is already considerably greater than the efficiency of PERC solitary cells.

The research study was released in Solar RRL.