Electron Donor‐Functionalized Pyrenes with Amplified Spontaneous Emission for Violet–Blue Electroluminescent Devices Beyond the Spin Statistical Limit

Abstract Direct electrically pumped organic lasers remain inaccessible to date, due to an interplay of different adverse effects. The most important of these effects are insufficient charge carrier mobility in the organic material, accumulation of triplet excitons upon charge injection, and absorption from the electrodes in the device. While triplet state management can be achieved using molecules that recycle triplet states into emissive singlet states, these molecules rarely support amplified emission. Pyrene derivatives not only show excellent charge transport properties, but their rigid π‐conjugated structure also entails excellent electro‐ and photoluminescence efficiency. Pyrenes exhibit very low‐lying first excited triplet states, rendering this class of molecules interesting for ultrafast upper‐level reverse intersystem crossing. This process counteracts the triplet accumulation in organic lasers. Here, pyrenes are functionalized with electron‐rich moieties of different donor strengths. Through comprehensive spectroscopic and quantum chemical analysis, the character of the charge transfer excited state is correlated with optical properties, excited state lifetimes, amplified spontaneous emission, and triplet recycling. Two donor functionalized pyrenes are reported with violet–blue emission that overcome the spin‐statistical limit of conventional organic emitters with spin factors η ST of up to 0.43 and low thresholds for amplified spontaneous emission E th down to 1.73 µJ cm −2 .

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Publication Details

Journal
Advanced Functional Materials
Published
2024-12-06
DOI
https://doi.org/10.1002/adfm.202417129
Citations
7
Primary Topic
Organic Light-Emitting Diodes Research
Type
article
Field-Weighted Citation Impact
1.46

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article

Electron Donor‐Functionalized Pyrenes with Amplified Spontaneous Emission for Violet–Blue Electroluminescent Devices Beyond the Spin Statistical Limit

Philipp Welscher, Alexander J. C. Kuehne, Birgit Esser, Florian Stümpges et al.
7 citations
Advanced Functional Materials
Organic Light-Emitting Diodes Research
1.46
article

Electron Donor‐Functionalized Pyrenes with Amplified Spontaneous Emission for Violet–Blue Electroluminescent Devices Beyond the Spin Statistical Limit

Philipp Welscher, Alexander J. C. Kuehne, Birgit Esser, Florian Stümpges, A. Lennart Respondek, Daniel Straub
article en
7 citations

Abstract

Abstract Direct electrically pumped organic lasers remain inaccessible to date, due to an interplay of different adverse effects. The most important of these effects are insufficient charge carrier mobility in the organic material, accumulation of triplet excitons upon charge injection, and absorption from the electrodes in the device. While triplet state management can be achieved using molecules that recycle triplet states into emissive singlet states, these molecules rarely support amplified emission. Pyrene derivatives not only show excellent charge transport properties, but their rigid π‐conjugated structure also entails excellent electro‐ and photoluminescence efficiency. Pyrenes exhibit very low‐lying first excited triplet states, rendering this class of molecules interesting for ultrafast upper‐level reverse intersystem crossing. This process counteracts the triplet accumulation in organic lasers. Here, pyrenes are functionalized with electron‐rich moieties of different donor strengths. Through comprehensive spectroscopic and quantum chemical analysis, the character of the charge transfer excited state is correlated with optical properties, excited state lifetimes, amplified spontaneous emission, and triplet recycling. Two donor functionalized pyrenes are reported with violet–blue emission that overcome the spin‐statistical limit of conventional organic emitters with spin factors η ST of up to 0.43 and low thresholds for amplified spontaneous emission E th down to 1.73 µJ cm −2 .

Advanced Functional MaterialsVol. 35(11)
Universität Ulm (DE)
Deutsche Forschungsgemeinschaft, Universität Ulm
Openalex Percentile: Top 17%
Organic Light-Emitting Diodes Research
1.46
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