Light‐Trapping Front Textures for Solar Cells from Tailored Mixtures of Nanospheres: A Numerical Study

• Published in: Physica status solidi. A, Applications and materials science Applications and materials science, 2018-12, Vol.215 (24), p.n/a
• Main Authors: Nanz, Stefan, Abass, Aimi, Piechulla, Peter M., Sprafke, Alexander, Wehrspohn, Ralf B., Rockstuhl, Carsten
• Format: Article
• Language: English
• Subjects: Broadband; Circuits; Crystal structure; Crystallinity; diffraction; light‐trapping; Nanospheres; nanostructures; Photovoltaic cells; Reflectance; Reflection; Silicon; Solar cells; Substrates; Texture
• ISSN: 1862-6300; 1862-6319
• DOI: 10.1002/pssa.201800699

Highly efficient anti‐reflection textures for solar cells that allow a fabrication using a two‐step bottom‐up approach are reported. Hereby, nanospheres of tailored sizes are deposited as a monolayer on a substrate and the resulting height profile is used as a template for structuring the silicon surface. By applying these textures to crystalline silicon solar cells, it is numerically shown that such interfaces provide excellent broadband suppression of reflection while also enhancing the effective path‐length through oblique‐angle scattering into the medium. Reflectance values around 5% can be reached and sustained for incident angles up to 40°. The short‐circuit current density obtained with the disordered texture and assuming two‐pass absorption in 10 µm thick crystalline silicon reaches 25.3 mA cm−2, which is close to the corresponding value achievable with a Lambertian texture (27.9 mA cm−2). Considering the simplicity and low cost of the approach, these textures may serve as a promising alternative to other often used anti‐reflection textures, especially for large‐scale devices. A numerical analysis of disordered nanostructured surface textures is performed that can be fabricated using a bottom‐up approach with nanospheres. Envisioned for the use in thin‐film solar cells, these disordered textures provide favorable anti‐reflection and light‐trapping properties due to broadband suppression of reflection and large‐angle forward scattering and are easy scalable for large‐scale devices.