Room-temperature phosphorescence from purely organic materials

Liu, Yang; Zhan, Ge; Liu, Zhiwei; Bian, Zuqiang; Huang, Chunhui

doi:10.1016/j.cclet.2016.06.029

Cited by 98 publications

(49 citation statements)

References 57 publications

(22 reference statements)

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“…[1][2][3] As opposed to loosely bonded electrons in organometallic materials,t he highly bonded nature of electrons in pure organic materials restricts their ability to decay through radiative relaxation pathways from triplet states. [6][7][8][9][10][11][12][13] These discoveries sparked several attempts to find ag eneral strategy to design more of such materials for various applications.Itwas found that to yield efficient RTP, several key factors have to be considered. [4] In addition, the triplet states are easily quenched by atmospheric oxygen molecules through triplet-triplet energy transfer.…”

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confidence: 99%

“…Therefore,triplet states in organic materials are prone to nonradiative relaxations through thermal and collisional processes. [6][7][8][9][10][11][12][13] These discoveries sparked several attempts to find ag eneral strategy to design more of such materials for various applications.Itwas found that to yield efficient RTP, several key factors have to be considered. As such, intensely phosphorescent materials are largely known to exist in inert gases and at very low temperatures,w hich in turn limits their practical applications.…”

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confidence: 99%

“…designed an on-planar structure comprised of ap henylphosphine and two carbazolyl groups.T wo factors were considered in their design to yield higher brightness and longer lifetime.F irstly, O, N, and Pa toms were used to favor the ISC transition, thanks to the lone-pair electrons.Moreover,substituents were included in the chemical structure to enhance the formation of H-aggregates,which stabilized the triplet excited state and therefore increased the lifetime.T he resulting pure phosphorescent crystals showed red emission with al ifetime of more than 1s .However,the quantum yield of the crystals was only around 2%. 1 H, 13 Figure S5. They combined the advantages of na nd p units through electronic coupling of two adjacent molecules,which in turn produced hybrid ISC transitions and resulted in bright long-lived RTP.…”

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confidence: 99%

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Organic Nanocrystals with Bright Red Persistent Room‐Temperature Phosphorescence for Biological Applications

et al. 2017

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Persistent room-temperature phosphorescence (RTP) in pure organic materials has attracted great attention because of their unique optical properties. The design of organic materials with bright red persistent RTP remains challenging. Herein, we report a new design strategy for realizing high brightness and long lifetime of red-emissive RTP molecules, which is based on introducing an alkoxy spacer between the hybrid units in the molecule. The spacer offers easy Br-H bond formation during crystallization, which also facilitates intermolecular electron coupling to favor persistent RTP. As the majority of RTP compounds have to be confined in a rigid environment to quench nonradiative relaxation pathways for bright phosphorescence emission, nanocrystallization is used to not only rigidify the molecules but also offer the desirable size and water-dispersity for biomedical applications.

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Organic Nanocrystals with Bright Red Persistent Room‐Temperature Phosphorescence for Biological Applications

et al. 2017

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“…This should be ascribed to their p ‐RTP emissions. If one considers the absence of RTP in solution, doped poly(methyl methacrylate) film, and molecularly dispersed “solid solution” into a TLC plate (data not shown here), the bright p ‐RTP in crystals implies the crystallization‐induced phosphorescence (CIP) of AN‐MA, which is widely observed in pure organic luminogens owing to the effective intra‐ and intermolecular interactions . Upon excitation with 312 nm UV light, the main emission peaks are located at 387/423/487 and 384/425/487 nm for form A and B (Figure B), respectively.…”

Section: Resultsmentioning

confidence: 96%

“…Recently,p ure organic luminogens with room-temperature phosphorescence (RTP) [1][2][3][4] have attracted increasing attention owing to their fundamentali mportance in deciphering the photophysical processes of singleta nd triplet excitons, [5][6][7][8][9][10] as well as their potentiala pplications in sensing, [5,[11][12][13] bioimaging, [14][15][16] anticounterfeiting, [8,[17][18][19] and so forth. In particular, those with persistent RTP (p-RTP) are also promising owing to the retaining of RTP emissione ven after ceasing the excitation sources, which means they can be used in encryption, oxygen and chemical sensing, and high-resolution molecular imaging with ideal signal-to-noise ratios.…”

Section: Introductionmentioning

confidence: 99%

Polymorphic Pure Organic Luminogens with Through‐Space Conjugation and Persistent Room‐Temperature Phosphorescence

Zhang

Zhao

et al. 2019

Chemistry An Asian Journal

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Pure organic luminogens with persistent room‐temperature phosphorescence (p‐RTP) have attracted increasing attention owing to their vital significance and potential applications in security inks, bioimaging, and photodynamic therapy. Previously reported p‐RTP luminogens normally possessed through‐bond conjugation. In this work, we report a pure organic luminogen, AN‐MA, the Diels–Alder cycloaddition adduct of anthracene (AN) and maleic anhydride (MA), which possesses isolated phenyl groups and an anhydride moiety. AN‐MA exhibits aggregation‐enhanced emission (AEE) characteristics with efficiency of approximately 2 % and up to 8.5 % in solution and crystals, respectively. Two polymorphs of AN‐MA were readily obtained that were able to generate UV emission from individual phenyl rings together with bright blue emission owing to the effective through‐space conjugation. Moreover, p‐RTP with a lifetime of up to approximately 1.6 s was obtained in the crystals. These results not only reveal a new system with both fluorescence and RTP dual emission but also suggest an alternative through‐space conjugation strategy towards pure organic p‐RTP luminogens with tunable emissions.

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Unexpected Quasi‐Axial Conformer in Thermally Activated Delayed Fluorescence DMAC‐TRZ, Pushing Green OLEDs to Blue

Stavrou

Franca

Böhmer

et al. 2023

Adv Funct Materials

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Hidden photophysics is elucidated in the very well‐known thermally activated delayed fluorescence (TADF) emitter, DMAC‐TRZ. A molecule that, based on its structure, is considered not to have more than one structural conformation. However, based on experimental and computational studies, two conformers, a quasi‐axial (QA) and a quasi‐equatorial (QE) are found, and the effect of their co‐existence on both optical and electrical excitation isexplored. The relative small population of the QA conformer has a disproportionate effect because of its strong local excited state character. The energy transfer efficiency from the QA to the QE conformer is high, even at low concentrations, dependent on the host environment. The current accepted triplet energy of DMAC‐TRZ is shown to originate from the QA conformer, completely changing the understanding of DMAC‐TRZ. The contribution of the QA conformer in devices helps to explain the good performance of the material in non‐doped organic light‐emitting diodes (OLEDs). Moreover, hyperfluorescence (HF) devices, using v‐DABNA emitter show direct energy transfer from the QA conformer to v‐DABNA, explaining the relatively improved Förster resonance energy transfer efficiency compared to similar HF systems. Highly efficient OLEDs where green light (TADF‐only devices) is converted to blue light (HF devices) with the maximum external quantum efficiency remaining close to 30% are demonstrated.

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Room-temperature phosphorescence from purely organic materials

Cited by 98 publications

References 57 publications

Organic Nanocrystals with Bright Red Persistent Room‐Temperature Phosphorescence for Biological Applications

Organic Nanocrystals with Bright Red Persistent Room‐Temperature Phosphorescence for Biological Applications

Polymorphic Pure Organic Luminogens with Through‐Space Conjugation and Persistent Room‐Temperature Phosphorescence

Unexpected Quasi‐Axial Conformer in Thermally Activated Delayed Fluorescence DMAC‐TRZ, Pushing Green OLEDs to Blue

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