Double‐sided nano‐textured surfaces for industry compatible high‐performance silicon heterojunction and perovskite/silicon tandem solar cells

Abstract

Nano‐textured surfaces are an intriguing approach for optimizing the optical characteristics for monolithic perovskite/silicon tandem solar cells. Here, the development of different textures of silicon surfaces using various commercial additives is presented and their performance in silicon heterojunction (SHJ) and SHJ–perovskite tandem solar cells is discussed. After optical and electrical characterization, we show that nano‐textured surfaces can easily compete with standard textured surfaces, yielding higher average efficiencies in single junctions. In addition, their compatibility with solution‐processed perovskite top cells is demonstrated, yielding a perovskite/silicon tandem solar cell efficiency of >28% on a bottom cell with nano‐texture on both sides.

Nanoscale Size Control of Si Pyramid Texture for Perovskite/Si Tandem Solar Cells Enabling Solution‐Based Perovskite Top‐Cell Fabrication and Improved Si Bottom‐Cell Response

“…In terms of the nanoscale texture design, a similar approach has been reported where the Si nanopyramid texture with an average size of 500 nm was used for solution processing of perovskite top cells in monolithic two-terminal perovskite/Si tandem solar cells. [28] The size of the pyramid texture they used agrees well with our optimal texture size (i.e., A 420nm or B 530nm ) for perovskite deposition. Nevertheless, their results show no distinct improvement in either top-cell or bottom-cell current, which is different from our observation.…”

“…However, there are limited reports on the practical applications of the solution‐processed Si nanostructures in perovskite/Si tandem solar cells. [ 28 ] In particular, there is still a lack of detailed research regarding the actual impact of the size and morphology of nanoscale Si textures on the interface properties and performance of perovskite/Si tandem solar cells.…”

Comparative Optical Analysis of Imprinted Nano‐, Micro‐ and Biotextures on Solar Glasses for Increased Energy Yield

“…The nanotextures shown in Figure 2a–c are outlined in red and consist of a moth‐eye structure (by temicon GmbH [ 14 ] ) with a surface covered in a fine array of protuberances (Figure 2a), a sinusoidal texture arranged in a hexagonal array (Figure 2b), both originally formed by laser interference lithography, and random nanopyramids produced by wet‐chemical etching with potassium hydroxide (KOH), potassium silicate (K 2 SiO 3 ), and a commercial additive in silicon wafers (Figure 2c). [ 15 ] The feature sizes of these nanotextures are found in the submicron range, with lateral dimensions ranging from 280 to 930 nm and vertical dimensions ranging from 70 to 310 nm. The artificial microtextures depicted in Figure 2d–f are outlined in blue and include hexagonally arranged microlens arrays (Figure 2d) produced by a combination of lithography and reflow processes, KOH‐etched random micropyramids in silicon (Figure 2e), and a stochastically textured wide‐angle circular diffuser (by temicon GmbH [ 16 ] ) specified with a scattering angle of 125° (FWHM) (Figure 2f).…”

“…Scanning electron microscopy images of selected a–c) nanotextures (red), d–f) microtextures (blue), and g–i) replicated biotextures (green). The SEM images of the master structures are shown for the a) moth‐eye structure (by temicon GmbH), b) sinusoidal (hexagonal lattice)—silver evaporated, c) random nanopyramids in silicon, d) microlens array (by temicon GmbH [ 14 ] ), e) random micropyramids in silicon, [ 15 ] and f) wide‐angle circular diffuser (by temicon GmbH [ 16 ] ). SEM images of replicated structures in resist on glass are shown for g) lotus leaf, h) poinsettia leaf, and i) rose petal.…”

“…The high SEF of 3.9 for the rose texture may also arise from its packing efficiency, where each structural element is closely packed to its adjacent features as can be seen in Figure 2i. A densely packed structure translates into efficient utilization rated, c) random nanopyramids in silicon, d) microlens array (by temicon GmbH [14] ), e) random micropyramids in silicon, [15] and f ) wide-angle circular diffuser (by temicon GmbH [16] ). SEM images of replicated structures in resist on glass are shown for g) lotus leaf, h) poinsettia leaf, and i) rose petal.…”