A series of tricyclic naphthothiophenes – photocyclization products (8-methoxynaphtho1,2-bthiophene; 6,7-dimethoxynaphtho1,2-bthiophene; 8-methoxynaphtho2,1-bthiophene) have been studied. HOMO and ...LUMO levels, as well as a gap between them was accessed by cyclic voltammetry and optical spectroscopy. Double potential step chronoamperometry showed that the former naphthothiophene exhibits slower current decay than the other substances. Charge carrier mobility measured by the CELIV technique was estimated to be of the order of 10−4 cm2V−1s−1 for 0.2 µm films and approaches 10−1 cm2V−1s−1. for the 5 µm film of 8-methoxynaphtho1,2-bthiophene. It is believed the high mobility is associated with the ordering of the high conductivity axis of the microcrystals in the layers.
•Methoxy-substituted naphthothiophenes have herringbone-type arrangement in crystals.•Thin films (0.2 µm) exhibit charge carrier mobilities of ca. 10−4 cm2V−1s−1.•Films of 5 µm thickness demonstrate charge carriers mobilities of the order of 10−1 cm2V−1s−1.
Electronic Processes in OLED Structures Mal’tsev, E. I.; Lypenko, D. A.; Tameev, A. R. ...
Russian journal of coordination chemistry,
12/2023, Volume:
49, Issue:
Suppl 1
Journal Article
Peer reviewed
Basic processes of the electroluminescence phenomenon in OLED structures are described. The conventional theoretical models for injection, transport and recombination of charge carriers and their ...relationship with the obtained experimental data are discussed. The mobility of charge carriers is a key characteristic of the electron and hole transport. Methods for measuring mobility that adequately reflect the transport of charge carriers in OLEDs are considered.
Light-emitting diodes are budget-friendly solid-state light sources that find use in the very diverse areas: from lighting to data display devices. The history of the discovery of the ...electroluminescence phenomenon and development of the technology of inorganic (LED) and organic light-emitting diodes (OLED) is presented. Today, there has been a widespread transition to light-emitting diode sources based on inorganic semiconductors, ensuring significant energy savings. However, OLED technologies continue to undergo intensive development. Advantages of OLED over other light sources and areas of their practical use are considered. We discussed the fundamental principles of manufacturing organic light sources with a white emission spectrum, based on low-molecular-weight and polymeric compounds, and considered various approaches for developing polymeric materials with a white emission spectrum. Prospects of the development of the market of OLED light sources are evaluated.
This review summarizes the results of the synthesis, photoluminescence, and electroluminescence of the main classes of cyclometallated iridium(III) complex compounds. The primary focus of the review ...is on heteroleptic iridium(III) complexes, which contain two equivalent C^N ligands and an additional auxiliary ligand. Numerous examples demonstrate that the selection and modification of the ligand systems in iridium(III) complexes, using various donor or acceptor groups, alter significantly their spectral characteristics, often achieving record levels of brightness and emission efficiency for OLED devices manufactured based on them.
The possibility of using push-pull systems based on furazanopyrazine in organic light-emitting diodes (OLEDs) and photovoltaic film devices was shown for the first time. The emission of all the ...obtained light-emitting diodes had a yellow-green color, and a maximum brightness of 45600 cd m
−2
was achieved at a maximum current efficiency of 2.9 cd A
−1
. It was determined that the mobility of charge carriers measured in different current modes for these push-pull systems ranged from 10
−4
to 4 · 10
−6
cm
2
V
−1
s
−1
, considerably exceeding the values of the well-known compound Spiro-MeOTAD, widely used in high-efficiency photovoltaic devices.
The review is devoted to analysis of photo- and electroluminescent properties of metal complexes (Al, Be, Mg, Ga, In, Zn, and B) based on substituted quinoline derivatives. Literature data shows that ...changing the substituents in quinoline ligands and the metal complexing agent can affect the color and intensity of photoluminescence in the corresponding metal complexes. OLED devices fabricated based on these complexes have exhibited high brightness and efficient electroluminescence across a broad spectral range from red to blue. Furthermore, these compounds possess excellent electron-transport properties, enabling their utilization as conductive layers in OLEDs.
This review article explores and analyzes published data on the photoluminescence and electroluminescence characteristics of rare earth element (REE) complex compounds, which are promising materials ...for creating highly efficient OLED devices. Distinguishing features of such compounds include their narrow emission bands, Stokes shift, long lifetime, and high quantum yields, enabling high resolution and color purity in constructed OLED devices. Using REE complexes as emissive layers in light-emitting diodes ensures significant color saturation and high device efficiency.
The article represents a translated, revised, and updated Section 6.3 of the monograph by A.S. Burlov, V.G. Vlasenko, D.A. Garnovskiy, A.I. Uraev, E.I. Maltsev, D.A. Lypenko, and A.V. Vannikov,
...Electroluminescent Organic Light-Emitting Diodes Based on Metal Coordination Compounds
, Rostov-on-Don: Yuzhn. Fed. Univ., 2015; ISBN 978-5-9275-1469-4 (see Additional Information). This section is dedicated to reviewing the photoluminescence and electroluminescence properties of metal complexes based on bi- and polydentate ligands of the azomethine type (Schiff bases). Many metal complexes of Schiff bases find wide use as luminescent materials. One of the applications of these compounds is the use as emissive layers or dopants for manufacturing OLED. The photo- and electroluminescence properties of a series of the metal complexes with the ligands based on the derivatives of hydroxybenzaldehyde, 2-(
N
-tosylamino)benzaldehyde, 1‑phenyl-3-methyl-4-formylpyrazol-5-one, and some others are reviewed. The systematic categorization of these compounds extends beyond their photophysical properties to consider the electroluminescence characteristics observed in OLED devices employing them as the basis. By modifying known azomethine-type ligand systems, one can obtain metal complex compounds with exceptional thermal stability, solubility, and quantum efficiency. These characteristics enable their use as luminescent materials in highly efficient OLED devices.
The article represents a translation of Section 6.2 of the monograph authored by A.S. Burlov, V.G. Vlasenko, D.A. Garnovskiy, A.I. Uraev, E.I. Maltsev, D.A. Lypenko, and A.V. Vannikov,
...Electroluminescent Organic Light-Emitting Diodes Based on Metal Coordination Compounds
, Rostov-on-Don: Yuzhn. Fed. Univ., 2015; ISBN 978-5-9275-1469-4 (see Additional Information), dedicated to reviewing the photoluminescence and electroluminescence properties of metal complexes based on (Zn, Cd, Al, Sc, Be, B) with azoles (2-(2-hydroxyphenyl)benzothiazoles, 2-(2-hydroxyphenyl)benzoxazoles, 2-(2-hydroxyphenyl)benzimidazoles, azaindoles, oxadiazoles, and their derivatives) as ligands. Modifying such ligands by introducing electron-donating substituents into various positions of the phenyl fragments leads to significant changes in their electroluminescence characteristics. Metal complex compounds with ligands of this type are widely used for creating OLED devices emitting white light.
The effect of addition of
J
-aggregates of polymethine dye into the hole-transport layer of an organic light-emitting diode (OLED) on its characteristics and operational stability was studied. ...Water-soluble PEDOT:PSS (poly(3,4-ethylenedioxythiophene)) and the interpolymer complex of polyaniline and poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAn-PAMPSA) were used as the matrices of polymer nanocomposites. The highest efficiency characteristics of the OLEDs with the considered structure were achieved using PAn-PAMPSA at a particular component ratio in the interpolymer complex. Additives of
J
‑aggregates did not significantly affect the efficiency characteristics of the OLEDs; however, an increase in the operational stability of devices was recorded.
