A route towards high‐efficiency silicon heterojunction solar cells

Abstract

In this work, we propose a route to achieve a certified efficiency of up to 24.51% for silicon heterojunction (SHJ) solar cell on a full-size n-type M2 monocrystalline-silicon Cz wafer (total area, 244.53 cm 2 ) by mainly improving the design of the hydrogenated intrinsic amorphous silicon (a-Si:H) on the rear side of the solar cell and the back reflector. A dense second intrinsic a-Si:H layer with an optimized thickness can improve the vertical carrier transport, resulting in an improved fill factor (FF). In order to reduce the plasmonic absorption at the back reflector, a low-refractive-index magnesium fluoride (MgF 2 ) is deposited before the Ag layer; this leads to an improved gain of short circuit current density (J sc ). In total, together with MgF 2 double antireflection coating and other fine optimizations during cell fabrication process, $1% absolute efficiency enhancement is finally obtained. A detailed loss analysis based on Quokka3 simulation is presented to confirm the design principles, which also gives an outlook of how to improve the efficiency further.

Monolithic Perovskite–Perovskite–Silicon Triple-Junction Tandem Solar Cell with an Efficiency of over 20%

“…Its corresponding cross-sectional scanning electron microscopy (SEM) image is shown in Figure b. For the bottom cell, we use a rear-textured silicon heterojunction cell with double-sided hydrogenated amorphous silicon (a-Si:H) passivations with proven high voltage outputs . For the middle- and high-band-gap perovskite solar cells, the MA-free (MA = methylammonium) triiodide Cs 0.1 FA 0.9 PbI 3 (FA = formamidinium) perovskite and MA-free mixed halide Cs 0.2 FA 0.8 Pb­(I 0.45 Br 0.55 ) 3 perovskite are used, respectively.…”

Impermeable Atomic Layer Deposition for Sputtering Buffer Layer in Efficient Semi‐Transparent and Tandem Solar Cells via Activating Unreactive Substrate

“…The detailed process information of double‐side polished silicon solar cells can be found in the authors’ previous work. [ 34 ] The bandgap of the perovskite in the tandem solar cells was 1.71 eV (composition Cs 0.05 FA 0.70 MA 0.25 PbI 2.25 Br 0.75 , Figure S14, Supporting Information). The best two‐terminal perovskite/silicon tandem solar cell delivered a PCE of 23.31% (steady‐state PCE of 22.93%, Figure S15, Supporting Information), with a J SC of 16.31 mA cm −2 , a V OC of 1.82 V, and an FF of 78.32% (Figure 4e and Table 1 ).…”

Transparent Conductive Oxide Sputtering Damage on Contact Passivation in Silicon Heterojunction Solar Cells with Hydrogenated Nanocrystalline Silicon

“…[ 23 ] The front total contact resistivity was determined by the transfer‐length method (TLM) with a specific pattern, details of which can be found in ref. [24,25] To evaluate the solar cells performance, current–voltage ( J – V ) characteristics were measured under standard test conditions (AM1.5, 25 °C, and 100 mW cm −2 ) by the LOANA system from pv‐tools with a Wavelabs Sinus 220 light source. The external quantum efficiency (EQE) and reflectance ( R ) were measured on a 20 20 mm 2 area of the cells with grids inside.…”