Impedance characterization of organic light-emitting structures with thermally activated delayed fluorescence A. V. Voytsekhovskii, S. N. Nesmelov, S. M. Dzyadukh [et al.]
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ArticleContent type: Текст Media type: электронный Subject(s): импеданс | органические светоизлучающие структурыGenre/Form: статьи в журналах Online resources: Click here to access online
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Physica status solidi A : applications and materials science Vol. 217, № 6. P. 1900847 (1-6)Abstract: The organic light-emitting device (OLED) structures based on layer (2,8-bis[N,Ndi(
4 methoxyphenyl)amino]dibenzothiophene-S,S-dioxide) with thermally activated
delayed fluorescence (TADF) are created. The properties of TADF-based
structures are studied by measuring the impedance under various conditions
(100 Hz–2MHz and 10–300 K). The features of the capacitance–voltage curves of
the studied structures can be explained by the simultaneous injection of holes
from the anode and electrons from the cathode. Cole–Cole plots are studied at
various voltages and temperatures. It is shown that at forward bias voltages, the
impedance is determined by single relaxation process and at low voltages by
more than one process. An OLED equivalent circuit consisting of four serial
capacitance–resistance (CR) chains (CR–CR–CR–CR) is proposed. Using this
circuit allows us to achieve good agreement between the calculated and experimental
frequency dependences of the impedance at various voltages. The different
elements of the equivalent circuit are associated with different layers in a multilayer
OLED structure. The dependences of the CR element values on the bias voltage are
found, and the thicknesses of the corresponding layers are determined.
Библиогр.: 37 назв.
The organic light-emitting device (OLED) structures based on layer (2,8-bis[N,Ndi(
4 methoxyphenyl)amino]dibenzothiophene-S,S-dioxide) with thermally activated
delayed fluorescence (TADF) are created. The properties of TADF-based
structures are studied by measuring the impedance under various conditions
(100 Hz–2MHz and 10–300 K). The features of the capacitance–voltage curves of
the studied structures can be explained by the simultaneous injection of holes
from the anode and electrons from the cathode. Cole–Cole plots are studied at
various voltages and temperatures. It is shown that at forward bias voltages, the
impedance is determined by single relaxation process and at low voltages by
more than one process. An OLED equivalent circuit consisting of four serial
capacitance–resistance (CR) chains (CR–CR–CR–CR) is proposed. Using this
circuit allows us to achieve good agreement between the calculated and experimental
frequency dependences of the impedance at various voltages. The different
elements of the equivalent circuit are associated with different layers in a multilayer
OLED structure. The dependences of the CR element values on the bias voltage are
found, and the thicknesses of the corresponding layers are determined.
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