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Indexed by:期刊论文

Date of Publication:2019-04-01

Journal:JOURNAL OF LUMINESCENCE

Included Journals:SCIE、Scopus

Volume:208

Page Number:46-50

ISSN No.:0022-2313

Key Words:Oxygen sensing; Luminescence mechanism; Quenching

Abstract:Triphenylamine-based cyclometalated platinum(II) (TCP) emits phosphorescence at room temperature. The phosphorescence was quenched by oxygen molecule, which means that TCP is a good candidate for oxygen molecule recognition and measurement. By the way of quantum chemical calculation, we proposed the quenching mechanism to elucidate the nature of oxygen sensing, which was different from the traditional dynamic collision mechanism. The luminescence mechanism of TCP involves phosphorescent emission, and the TCP-O-2 complex fluorescent emission. By utilizing the density functional theory (DFT) method, we calculated the electron configurations and the frontier molecular orbitals of TCP and the TCP-O-2 complex. Furthermore, applying the time-dependent density functional theory (TDDFT) method, we calculated the geometric optimization and the excitation energies of TCP and the TCP-O-2 complex in the excited state. The results illustrate that the luminescence of TCP stems from localized excitation, while that of the TCP-O-2 complex stems from delocalized excitation. Moreover, we also calculated the radiative and non-radiative rate constants of TCP and the TCP-O-2 complex and clarified the photophysical processes of them. For TCP, first the electron arrived at the T-1 state via intersystem crossing from the initial S-1 state and finally back to the S-0 state via emitting phosphorescence. For the TCP-O-2 complex, with no spin flip, the electron jumped directly from the T-1 to T-0 state via internal conversion.