TY - JOUR
T1 - A ground-state-dominated magnetic field effect on the luminescence of stable organic radicals
AU - Kimura, Shun
AU - Kimura, Shojiro
AU - Kato, Ken
AU - Teki, Yoshio
AU - Nishihara, Hiroshi
AU - Kusamoto, Tetsuro
N1 - Funding Information:
The present study was supported by JST CREST Grant Number JPMJCR15F2 and JSPS KAKENHI Grant Numbers JP20H02759, JP17H04870, JP19H05460, JP26220801, JP16H04136, and JP20H02715. T. K. is grateful to the Iketani Science and Technology Foundation and Kato Foundation for Promotion of Science for nancial support. Shu. K. acknowledges MERIT (Material Education program for the future leaders in Research, Industry, and Technology) in the MEXT Leading Graduate School Doctoral Program. This work was performed at the High Field Laboratory for Superconducting Materials, Institute for Materials Research, Tohoku University (Project No. 17H0018 and 16H0067).
Publisher Copyright:
© The Royal Society of Chemistry 2021.
PY - 2021/2/14
Y1 - 2021/2/14
N2 - Organic radicals are an emerging class of luminophores possessing multiplet spin states and potentially showing spin-luminescence correlated properties. We investigated the mechanism of recently reported magnetic field sensitivity in the emission of a photostable luminescent radical, (3,5-dichloro-4-pyridyl)bis(2,4,6-trichlorophenyl)methyl radical (PyBTM) doped into hostαH-PyBTM molecular crystals. The magnetic field (0-14 T), temperature (4.2-20 K), and the doping concentration (0.1, 4, 10, and 22 wt%) dependence on the time-resolved emission were examined by measuring emission decays of the monomer and excimer. Quantum mechanical simulations on the decay curves disclosed the role of the magnetic field; it dominantly affects the spin sublevel population of radical dimers in the ground states. This situation is distinctly different from that in conventional closed-shell luminophores, where the magnetic field modulates their excited-state spin multiplicity. Namely, the spin degree of freedom of ground-state open-shell molecules is a new key for achieving magnetic-field-controlled molecular photofunctions.
AB - Organic radicals are an emerging class of luminophores possessing multiplet spin states and potentially showing spin-luminescence correlated properties. We investigated the mechanism of recently reported magnetic field sensitivity in the emission of a photostable luminescent radical, (3,5-dichloro-4-pyridyl)bis(2,4,6-trichlorophenyl)methyl radical (PyBTM) doped into hostαH-PyBTM molecular crystals. The magnetic field (0-14 T), temperature (4.2-20 K), and the doping concentration (0.1, 4, 10, and 22 wt%) dependence on the time-resolved emission were examined by measuring emission decays of the monomer and excimer. Quantum mechanical simulations on the decay curves disclosed the role of the magnetic field; it dominantly affects the spin sublevel population of radical dimers in the ground states. This situation is distinctly different from that in conventional closed-shell luminophores, where the magnetic field modulates their excited-state spin multiplicity. Namely, the spin degree of freedom of ground-state open-shell molecules is a new key for achieving magnetic-field-controlled molecular photofunctions.
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U2 - 10.1039/d0sc05965j
DO - 10.1039/d0sc05965j
M3 - Article
AN - SCOPUS:85100938329
SN - 2041-6520
VL - 12
SP - 2025
EP - 2029
JO - Chemical Science
JF - Chemical Science
IS - 6
ER -