Exciplex: Its Nature and Application to<scp>OLEDs</scp>

Kim, Hwang-Beom; Kim, Dong-Wook; Kim, Jang‐Joo

doi:10.1002/9783527691722.ch10

Cited by 7 publications

(8 citation statements)

References 146 publications

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“…Excimers and exciplexes can also be joined in an intramolecular fashion through linkers, [53,56,60] although the mechanism still involves the chromophors.I nm aterials science, excimer and exciplex formation has found particular interest in 3rd generation OLEDs. [61,62] * Fort he sake of completeness,t wo more correlated emitter processes should be mentioned that have found particular application in organic photovoltaics,a nd which may lead to possible DE3. One is triplet-triplet annihilation (TTA, also known as p-type delayed FL, see Figure 1) [63] and the other one is singlet fission (SF) with the condition 2 E(T 1 ) < E(S 1 )).…”

Section: Dual Emission Processes Involving One or Twoemittersmentioning

confidence: 99%

Dual Emission: Classes, Mechanisms, and Conditions

2021

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There has been much interest in dual-emission materials in the past few years for materials and life science applications;h owever, asystematic overview of the underlying processes is so-far missing.We resolve this issue herein by classifying dual-emission (DE) phenomena as relying on one emitter with two emitting states (DE1), two independent emitters (DE2), or two correlated emitters (DE3). Relevant DE mechanisms for materials science are then briefly described together with the electronic and/or geometrical conditions under which they occur.F or further reading,references are given that offer detailed insight into the complex mechanistic aspects of the various DE processes or provide overviews on materials families or their applications. By avoiding ambiguities and misinterpretations,t his systematic, insightful Review might inspire future targeted designs of DE materials.

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Section: Dual Emission Processes Involving One or Twoemittersmentioning

confidence: 99%

Dual Emission: Classes, Mechanisms, and Conditions

2021

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“…In den Materialwissenschaften werden Excimerund Exciplexbildung in OLEDs der dritten Generation eingesetzt. [61,62] * Der Vollständigkeit halber sollten zwei weitere Prozesse korrelierter Emitter erwähnt werden, die speziell in der organischen Photovoltaik Interesse gefunden haben und die Abbildung 2. Photophysikalische Pfade der dualen Emission, die auf einem Emitter mit zwei emittierenden Zuständen (DE1), auf zwei un-abhängigenE mittern( DE2) oder zwei korrelierten Emittern (DE3) beruhen.…”

Section: Duale Emissionsprozesse Mit Einem Oder Zwei Emitternunclassified

“…In den Materialwissenschaften werden Excimerund Exciplexbildung in OLEDs der dritten Generation eingesetzt. [61,62] * Der Vollständigkeit halber sollten zwei weitere Prozesse korrelierter Emitter erwähnt werden, die speziell in der organischen Photovoltaik Interesse gefunden haben und die unter Umständen zu DE3 führen. Der eine Prozess ist die Tr iplett-Triplett-Annihilation, TTA( auch als "p-Type Delayed FL" bekannt, siehe Abbildung 1); [63] der andere ist Singlet Fission (SF), die unter der Bedingung 2 E(T 1 ) < E(S 1 ) stattfinden kann.…”

Section: Duale Emissionsprozesse Mit Einem Oder Zwei Emitternunclassified

Duale Emission: Klassen, Mechanismen und Bedingungen

2021

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zu finden.Dual emittierende (DE-)Verbindungen finden starkes Interesse in den Material-and Biowissenschaften;allerdings fehlt eine systematische Zusammenfassung der zugrundeliegenden Prozesse.Diese erfolgt hier durch eine Klassifizierung der DE-Phänomene,w obei zwischen Prozessen unterschieden wird, die einerseits auf nur einem Emitter mit zwei emittierenden Zuständen oder andererseits auf zwei unbhängigen Emittern oder zwei korrelierten Emittern beruhen. Danach werden die fürdie Materialwissenschaften relevanten DE-Mechnismen beschrieben, wobei die elektronischen und geometrischen Bedingungen herausgearbeitet werden, unter denen sie erfolgen;d ie weiterführende Literatur,auf die verwiesen wird, soll einen genaueren Einblick in die mechanistischen Aspekte der DE-Prozesse und einen Überblick über die Substanzklassen und ihre Anwendungen geben. Indem Zweideutigkeiten vermieden werden und auf Fehlinterpretationen hingewiesen wird, mag diese Übersicht die weitere gezielte Entwicklung von DE-Materialien fçrdern. Aus dem Inhalt 1. Einleitung 22805 2. Duale Emissionsprozesse mit einem oder zwei Emittern 22807 3. Materialien mit dualer Emission eines Emitters (DE1) 22809 4. Materialien mit dualer Emission von zwei korrelierten Emittern (DE3) 22814

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“…Exciplexes in blends of donor and acceptor organic semiconductors are rather common. − Their occurrence can be detected by the exciplex luminescence appearing as a strongly red-shifted broad structureless band, which frequently has low intensity. However, exciplexes are not always luminescent; therefore, it is likely that nonemissive exciplexes are abundant in such blends.…”

Section: Introductionmentioning

confidence: 99%

“…If the 1 CT state is nonemissive, the only electron−hole recombination channel is internal conversion. A chargetransfer triplet state 3 CT is often quasi-degenerate with 1 CT. Although the spin−orbit coupling between these states is small according to the El-Sayed rule, the intersystem crossing can be assisted by the presence of other close-lying states.…”

Section: ■ Introductionmentioning

confidence: 99%

Theoretical Study of Charge-Transfer Exciplexes in Organic Photovoltaics

2022

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The photogeneration of charges in bulk heterojunction organic photovoltaics is of crucial importance in the mechanism of charge separation. This results in the formation of both locally excited and charge-transfer exciplex states. While the former states are prone to radiative or nonradiative recombination, the latter ones can have a sufficiently long lifetime. In this work, the formation of charge-transfer exciplex states in pairs of PC61BM (acceptor) with different oligothiophenes (donors) is studied theoretically using density functional theory. The ground and excited states of three oligothiophene–PC61BM complexes are studied. It is found that the intensively absorbing state is localized on the oligothiophene. Another excited state is localized on PC61BM, being characterized by only slight absorption. The charge-transfer (CT) excited state of the complex lies either below or slightly higher than the locally excited (LE) states. The latter case is unfavorable for charge separation. Criteria for the efficient formation of charge-transfer exciplexes are found, and the possibility of oligothiophene modification to facilitate the formation of such exciplexes is explored. Shifting the donor absorption to the near IR, which is important for organic solar cells, is another goal of oligothiophene modification. A modified oligothiophene satisfying these two criteria is proposed. The structure and radiative lifetimes of the LE and CT states and also the binding energy of the CT states with respect to their dissociation into a radical cation and a radical anion are calculated. It is demonstrated that the lifetime of the CT exciplexes is sufficiently long to accomplish charge separation.

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Exciplex: Its Nature and Application toOLEDs

Cited by 7 publications

References 146 publications

Dual Emission: Classes, Mechanisms, and Conditions

Dual Emission: Classes, Mechanisms, and Conditions

Duale Emission: Klassen, Mechanismen und Bedingungen

Theoretical Study of Charge-Transfer Exciplexes in Organic Photovoltaics

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