PUBLICATION

Advanced Soft Energy Materials Lab

Publication

Publication

49. Size-Controlled LiDAR-detechable Black Pigmnets: Comparative Study from the Nano- to the Micro-scale
Authors
Jiwon Kim, Zambaga Otgobayar, Suk Jekal, Minki Sa, Dahee Kang, Jungchul Noh, Woo-Jin Song*, Chang-Min Yoon*
Journal
ACS Applied Optical Materials
Date
(2024.10)
Year
2024

Light detection and ranging (LiDAR) sensors emit pulsed near-infrared (NIR) lasers toward targets and detect the reflected signals to measure the distance between LiDAR-equipped autonomous vehicles and surrounding objects. However, LiDAR sensors have difficulty recognizing black and dark objects owing to their intrinsic light absorption characteristics, including NIR light, which limits their practical application in autonomous driving environments. In this study, NIR-reflective silica/black titania core/shell (SBT/CS) pigments of various sizes (140 nm, 1.3 μm, and 6.6 μm) ranging from the nano- to micron-scale are synthesized to evaluate the suitability of LiDAR-detectable paints in car coatings. The silica cores are fabricated using the Stöber method by adjusting the quantity of the reagents and then coated with a black titania shell via titanium tetrachloride sol–gel and NaBH4 reduction methods. In practical LiDAR applications, the SBT/CS pigments with 100 nm cores exhibit the highest NIR reflectance (27.8 R% at 905 nm) owing to their high specific surface area. Conversely, SBT/CS pigments with 6 μm cores demonstrate excellent spreadability and durability owing to their increased contact area and mechanical strength. All of the SBT/CS-painted objects are successfully recognized using commercial LiDAR sensors, thus confirming the advantages of micron-scaled SBT/CS-based paints in autonomous driving environments.