The race for the best silicon bottom cell: Efficiency and cost evaluation of perovskite–silicon tandem solar cells

Abstract

Perovskite-silicon tandem solar cells have shown a rapid progress within the past 5 years in terms of their research cell efficiency and are currently being investigated as candidates for the next generation of industrial PV devices. This raises the question of which silicon bottom cell will be most suitable for tandem application. Currently, the silicon heterojunction (SHJ) technology dominates in tandem research achieving world records. However, it is an open issue of how to transfer these research results to industrial mass production, which is driven by cost reduction and resource efficiency and includes challenges like upscaling and long-term stability. Therefore, it is highly relevant for the PV industry to get reliable and predictive estimates on the efficiency and cost potential, as well as technologically feasible solutions. In this work, we elaborate on silicon bottom cell concepts based on the PERC, TOPCon, and SHJ technology combined with two different interconnection concepts. For each tandem device, the efficiency potential is investigated by means of an experimentally validated simulation model. Second, we evaluate the bottom cell concepts in terms of all-in cell costs per piece. Bringing the efficiency potential and cost evaluation together allows us to assess the different tandem cell concepts in terms of all-in module cost per watt peak. Our results show that perovskite-silicon tandem devices are promising candidates to significantly reduce the levelized cost of electricity and, in particular, that the "race" for the best silicon bottom cell is still open to all the investigated bottom cell technologies.

Insights into the Development of Monolithic Perovskite/Silicon Tandem Solar Cells

“…Reproduced by permission. [ 201 ] Copyright 2020, John Wiley and Sons. d) Simulated LCOE ratios between a PK/c‐Si tandem module with variable PCEs and a 405 W PERC module in 2025.…”

“…investigated the impact of four promising silicon bottom cell candidates on device cost, namely P[E]RC (the front side features a highly doped emitter which contacted by TCO or p‐type poly‐Si without passivated layer), TOPerc (it has the same rear side and absorber as the P[E]RC structure, but the diffused n++‐emitter at the front side is replaced by 30‐nm‐thick n‐TOPCon structure), TOPCon, and SHJ, as shown in Figure 4b. [ 201 ] There is indeed a certain cost difference between different silicon cells, but it can be clearly seen that the cost difference between the bottom cell concepts is significantly reduced when including the effect of the increased tandem cell efficiency at the module level as shown in Figure 4c. [ 201 ] All tandem concepts show all‐in module costs exhibiting the lowest value and presenting the potential to be cost competitive compared with the PERC single junction reference (left side).…”

Electroplated Copper Metal Contacts on Perovskite Solar Cells

“…[1][2][3][4][5][6] Electrochemically deposited copper, already implemented in the integrated circuit industry, is a very promising approach to substitute Ag in solar cells. [7] Two-terminal perovskite silicon tandem solar cells, which are currently being investigated with the goal to overcome the silicon conversion efficiency limit [8,9] with slightly extra costs, [10][11][12][13] are also using silver electrodes. To date, only a few large-area tandem devices with Ag front-side grid (and also Au) are reported, deposited either by thermal evaporation [14,15] or by low-temperature Ag-paste screen printing.…”

High performance tandem perovskite-silicon solar cells with very large bandgap photoelectrodes

“…In tandem, perovskite-silicon (PSC/c-Si) solar cells PSCs are usually used as top elements in combination with bottom c-Si cells [8,9]. Tandem PSC/c-Si solar cells are commonly fabricated in two configurations: two-terminal and four-terminal [10,11].…”