부산대학교 도서관

Despite significant advantages in terms of portability and cost, near-infrared (NIR) gas sensing still remains a great challenge due to its relatively weak overtone absorption from the fundamental vibrational bond absorption at the mid-IR frequency. In this paper, we demonstrated ultra-sensitive NIR gas sensing for carbon dioxide (CO 2 ) at 1.57 μm wavelength through nanoporous Cu-BTC (BTC = benzene-1,3,5-tricarboxylate) metal-organic framework (MOF) coated single-mode optical fiber. For the first time, we obtained high-resolution NIR spectroscopy of CO 2 sorbed in MOF without seeing any rotational side band, indicating that the tightly confined gas molecules in the MOF pores do not have any freedom of rotation. Real-time measurement of the mixed gas flow of CO 2 and Ar showed different response time depending on the concentration of CO 2 , which is attributed to the complex sorption mechanism of CO 2 in Cu-BTC MOF. Most importantly, we realized ultra-low detection limit of CO 2 (<20 ppm) with only 5 cm long Cu-BTC MOF thin film coated on single-mode optical fibers. [ABSTRACT FROM AUTHOR]