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

• Published in: Advanced materials interfaces Vol. 10; no. 35
• Main Authors: Li, Yuqing, Sai, Hitoshi, McDonald, Calum, Xu, Zhihao, Kurokawa, Yasuyoshi, Usami, Noritaka, Matsui, Takuya
• Format: Journal Article
• Language: English
• Published: Weinheim John Wiley & Sons, Inc 01.12.2023; Wiley-VCH
• Subjects: Circuits; double‐sided nanotextured silicon; Efficiency; Etching; Industrial production; metal assisted anisotropic etching; Perovskites; Photovoltaic cells; Production costs; Screen printing; Silicon; silicon heterojunctions; Solar cells; solution process; Surface layers; Surfactants; tandem solar cells; Texture
• ISSN: 2196-7350; 2196-7350
• DOI: 10.1002/admi.202300504

A monolithic perovskite/silicon tandem solar cell architecture is employed to surpass the single‐junction efficiency limit. Recently, there is an increasing need for the double‐sided textures in the Si bottom cell to be compatible with the solution‐processed perovskite top cell from an industrial perspective. Herein, a silver‐assisted alkaline etching method is applied to fabricate nanoscale Si pyramid textures, and the influence of varying pyramid size (400–900 nm) on the interface morphology and the performance of perovskite/Si tandem cells is investigated. It is demonstrated that electrical shunting starts to increase, and the open‐circuit voltage (VOC) decreases when the texture size exceeds the perovskite thickness (~500nm) due to the non‐uniform top‐cell formation on a rough Si surface. However, when the texture size is reduced to 400–500 nm, all spin‐coated perovskite top‐cell component layers exhibit an even form over the nanopyramid Si, resulting in a high VOC and an enhanced Si bottom cell current (≈1.0 mA cm−2) due to the suppressed reflectance at the top/bottom cell interface without using optical couplers. The double‐sided nanopyramid Si texture offers opportunities to increase tandem cell efficiency while reducing its production cost compared with the commonly used single‐sided textured Si. In perovskite/silicon tandem solar cell architecture, the double‐sided Si texture compatible with the solution‐processed perovskite top cell is required. Herein, nanoscale Si pyramid textures are fabricated by the simple solution process and the optimum pyramid size (400–500 nm) is shown to provide an enhanced Si bottom cell current (≈1.0 mA cm−2) while retaining high open‐circuit voltage.