Soft imprinted Ag nanowire hybrid electrodes on silicon heterojunction solar cells

Highlights: • Ag nanowire meshes are controllably fabricated over large areas (4 cm²) using substrate-conformal imprint lithography (SCIL) • Nanowire meshes are significantly more conductive than an industrial 80 nm ITO layer • A hybrid nanowire/ITO/SiN_x electrode is demonstrated on silicon heterojunction (SHJ) solar cells • Current (J_sc) is increased by 2.1 mA cm⁻² compared to a reference cell via anomalous transmission, reduced ITO, and increased finger pitch • Cell efficiency improves by 1.0% absolute with the nanowire hybrid electrode We demonstrate enhanced efficiencies in front-contacted silicon heterojunction (SHJ) solar cells using silver nanowire-based hybrid electrodes. SHJ cells typically suffer from shading losses due to reflection from macroscopic sun-facing metal fingers, which must be closely spaced to avoid resistive losses in the transparent conductive electrode (TCE). Using substrate conformal imprint lithography (SCIL) we fabricate silver nanowire electrodes on practical scale (4.0 cm²) planar SHJ cells. These electrodes exhibit anomalous transmission and a 7-fold improvement in sheet conductance relative to a standard ITO layer, enabling larger finger spacings and reducing reflection losses without compromising the cell fill factor. Over 70% of the ITO is replaced with transparent SiN_x, reducing the use of indium while improving the anti-reflective performance. Combined, the reduced shading and reflection raises the short circuit current density increases by 2.1 mA cm⁻², yielding an absolute increase in cell efficiency of 1.0%. These engineered hybrid electrodes provide a practical pathway towards front-contacted SHJ cells with a reduced dependence on rare metals and high efficiencies.