Near-Infrared to Visible Photon Upconversion with Gold Quantum Rods and Aqueous Photo-Driven Polymerization
Zhongyu Liu, Xiaolei Hu, Lianshun Luo, Guiying He, Abhrojyoti Mazumder, Ece Gunay, Yitong Wang, Elizabeth C. Dickey, Linda A. Peteanu, Krzysztof Matyjaszewski, Rongchao Jin
Abstract
High Resolution Image Download MS PowerPoint Slide Converting near-infrared (NIR) photons into visible light via triplet–triplet annihilation upconversion (TTA-UC) is a promising strategy for advancing energy, biomedical, and materials science. However, the development of efficient NIR sensitizers remains a major challenge. Here, we report an atomically precise gold quantum rod, Au 42 (PET) 32 (PET = 2-phenylethanethiolate), as a high-performance photosensitizer for NIR-to-visible TTA-UC. Paired with TES-ADT as an annihilator, the system exhibits a 6.7% quantum yield, a 0.5 eV anti-Stokes shift, and a low threshold intensity of 90 mW/cm 2 . To enable aqueous compatibility, the upconversion nanodroplets are encapsulated with a silica shell, yielding Au 42 /TES-ADT@SiO 2 nanoparticles (NPs) capable of driving efficient photoinduced atom-transfer radical polymerization (photo-ATRP) and forming hydrogels in water. This system offers a versatile platform for the next generation photopolymerization with NIR light, solar energy utilization and noninvasive biomedical applications.