Monolithic Perovskite/Silicon Tandem Solar Cells Fabricated Using Industrial p‐Type Polycrystalline Silicon on Oxide/Passivated Emitter and Rear Cell Silicon Bottom Cell Technology

Abstract

Silicon solar cells have been the working horses of the photovoltaic industry for decades. Continuous technological progress has led to increases in power conversion efficiency (PCE) and driven the levelized cost of electricity (LCOE) down to 1.33 $ct kWh À1 in sunny regions such as Chile. [1] To continue this success story, the combination of a silicon bottom solar cell with a low-cost, wide-bandgap top cell into a tandem device is perceived as an intriguing technological path toward costeffective multijunction solar cells with PCEs beyond the silicon single-junction efficiency limit of 29.5%. [2] In particular, perovskite/silicon tandem solar cells have triggered impressive research and development that peaked in devices with PCEs approaching 30%. [3][4][5] However, as of late 2021, the majority of the reported monolithic perovskite/silicon tandem solar cells with highest PCE results rely on silicon heterojunction (SHJ) bottom cells, exploiting SHJ's high opencircuit voltages (see, e.g., Jost et al. for a recent review). [6] The

Perovskite/Silicon Tandem Solar Cells: Choice of Bottom Devices and Recombination Layers

“…Performing an appropriate front-side design of PERC solar cells with n + /p + -Si-based materials in the recombination layer can prevent the damage of sputtering (Figure a) . Furthermore, the front-side design results in better refractive index matching and significant reduction of optical losses. , Another improved front-side design has been achieved by substituting the diffused phosphorus emitter in PERC subcells with an electron-collecting passivating polycrystalline silicon on oxide (POLO) front junction, protecting the subcells from the sputtering of the recombination layer and making the fabrication of 2T tandem cells more compatible with the industrial mainstream PERC technology . In these PERC subcells of tandem devices, the TOPCon concept is introduced at the front side while the back-side structure of PERC solar cells remains.…”

“…31−35 Besides, improving the front side of PERC subcells can prevent the damage arising from the deposition, promote refractive index matching, suppress recombination, and reduce optical and transport losses in tandem cells. 36,37 TOPCon cells as the bottom cells in tandem devices benefit from the passivation of the contact area by the thin SiO x layer and the increased charge tunneling, suppressing recombination and facilitating unipolar charge transport. 38 HJT cells also use passivation in the contact to improve the performance of associated tandem devices.…”

Balancing Charge‐Carrier Transport and Recombination for Perovskite/TOPCon Tandem Solar Cells with Double‐Textured Structures

“…The J-V characteristic curves of these related cases are plotted in Figure 5D, and the corresponding electrical parameters are listed in Table 1, suggesting that: 1) the double-textured sample demonstrates an outstanding J sc with a value of 19.40 mA cm −2 , which is much higher than that of the double-polished (17.80 mA cm −2 ) and rear-textured (18.20 mA cm −2 ) ones; 2) due to the optical gain, the textured samples show a slightly higher V oc and FF; 3) a double-textured sample achieve a remarkable efficiency of 28.49%. [26][27][28][29][30] The corresponding EQE spectra demonstrated in Figure 5E reveal that the presence of the rear-side nano-structures could effectively promote light-trapping, especially in the infrared band, and samples with the double-textured structures could improve the optical absorption of almost the whole wavelength range that involved. Importantly, the iV oc s from bottom cell precursors with the different RF powers and annealing temperatures along with the corresponding device parameters of perovskite/ TOPCon TSCs are given in Figures S11 and S12, Supporting Information, suggesting that the efficiencies of these tandems show identical tendency with that of the passivation and contact properties.…”

Silicon solar cells with passivating contacts: Classification and performance

“…81 Similar to SHJ Si cells, the parasitic absorption in the poly-Si layers is less important because most of the short wavelength light is absorbed in the perovskite cell. Compared with SHJ-based Si bottom cells, poly-Si has better thermal stability and poses fewer restrictions in the selection and processing of the carrier selective contacts below the perovskite absorber, [82][83][84] Poly-Si has also been used to form the recombination junction in a tandem perovskitesilicon solar cell. A recombination junction with ITO and n-type poly-Si on a perovskite-silicon tandem solar cells has been demonstrated to allow a conversion efficiency of 21.3%.…”

“…A recombination junction with ITO and n-type poly-Si on a perovskite-silicon tandem solar cells has been demonstrated to allow a conversion efficiency of 21.3%. 84 The perovskite-silicon tandem solar cell with the p-type poly-Si deposited on top of the n-type poly-Si acting as the collecting junction in the Si bottom cell achieved an efficiency of 25.1%. 82…”