Preparation of LiDAR-detectable black pigments via recycling the silicon sludge generated from the semiconductor manufacturing processes

• Published in: Colloids and surfaces. A, Physicochemical and engineering aspects Physicochemical and engineering aspects, 2025-01, Vol.705, p.135741, Article 135741
• Main Authors: Sa, Minki, Otgonbayar, Zambaga, Kang, Dahee, Noh, Jungchul, Jekal, Suk, Kim, Jiwon, Yoon, Chang-Min
• Format: Article
• Language: English
• Subjects: Black TiO2; color; cost effectiveness; environmental sustainability; hydrofluoric acid; hydrophilicity; lidar; LiDAR sensor; NIR reflectance; Recycling; reflectance; Semiconductor; semiconductors; silicon; Silicon sludge; sludge; solid wastes; titanium dioxide
• ISSN: 0927-7757
• DOI: 10.1016/j.colsurfa.2024.135741

A novel LiDAR-detectable plate-like hollow black titanium dioxide (HbTiO2) is developed by recycling silicon sludge generated from silicon wafer sawing. By employing TiCl4 sol-gel synthesis, hydrofluoric acid etching, and NaBH4 reduction, the hollow-structured black TiO2 is successfully synthesized. Plate-like HbTiO2 readily mixed with hydrophilic varnish, owing to its inherent hydrophilic properties. With monolayer coating, HbTiO2-based paints exhibit the blackness (L* = 17.63) comparable to that of commercial black paints, indicating that NaBH4 successfully changed the color of TiO2 from white to black. In addition to its blackness, HbTiO2 exhibits a superior near-infrared (NIR) reflectance of ca. 26.8 R% at 905 nm, making it suitable for integration with the LiDAR systems used in autonomous vehicles. This high NIR reflectance ensures that HbTiO2 can effectively interact with the LiDAR sensors, attributing to the hollow structures and effective light reflection mechanism. Furthermore, the use of recycled silicon sludge not only offers a cost-effective alternative to traditional template materials but also promotes environmental sustainability by reducing solid waste. Our findings demonstrate the potential of HbTiO2 as an innovative and practical LiDAR-detectable black pigment, paving the way for advanced applications in autonomous vehicle technologies. [Display omitted] •Hollow black TiO2 (HbTiO2) is synthesized as NIR-reflective material.•Recycling silicon sludge as template is nominated first time.•With creation of hollow structure, the highest NIR reflection is measured.•Recycling silicon sludge promotes zero-waste and practical alternative templates.•In monolayer, HbTiO2-coated object successfully recognized by the LiDAR sensors.