123rd General Meeting of the KCS

Type Oral Presentation
Area Oral Presentation for Young Physical Chemists I
Room No. Room 305+306
Time THU 09:00-09:09
Code PHYS1.O-1
Subject A simple and accessible microscopic magnetic field mapping techniques using exciplex-based magnetosensing fluorophore: One- and Two-photon excitation
Authors Dongkyum Kim, Hohjai Lee1,*
Department of Chemistry, Gwangju Institute of Science and Technology, Korea
1Chemistry, Gwangju Institute of Science and Technology, Korea
Abstract We developed the simple and accessible fluorescence microscopic imaging system for mapping magnetic field. The system includes a fluorescent indicator, pyrene-(CH2)12-O-(CH2)2-N,N-dimethylaniline respond to magnetic field. Upon photo-excitation, the indicator forms an excited complex (exciplex) or spin-correlated radical ion pairs (RIP) via excited state quenching. The amount of exciplex emission (XplxE) generated by re-combined RIP could be influenced by an external magnetic field. Interconversion between electronic spin states in RIP under the magnetic field was described by the radical pair mechanism. In an optimized working solvent (anisole/DMF, v/v=50/50) and 375-nm illumination, its exciplex emission with an external magnetic field (>50 mT) becomes 1.33 times brighter than that with zero field. The increased amount of emission is sufficient for imaging within a short time. An image of magnetic field distribution in microscale was obtained by epi-microscopy. Since 375-nm LED lamp illumination and short data acquisition time, our imaging microscope was free from photo-bleaching. Using 375-nm light source enable to build microscope composed of common and low-cost optical material with high transmittance in 375 nm. We also demonstrated its feasibility for a 3D-image of magnetic field with two-photon fluorescence microscopy.
E-mail kdk5040@gist.ac.kr