Unusual room temperature afterglow in some crystalline organic compounds

Bilen, Chhinder; Harrison, N. T.; Morantz, D. J.

doi:10.1038/271235a0

Cited by 71 publications

(62 citation statements)

References 4 publications

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“…The distinct dual‐emissive Cu I ‐NHC complexes differ from traditional Cu I complexes. The two separate emission bands with vibronic features are quite similar with the fluorescence and RTP from solid carbazole or Cz derivatives, suggesting singlet and triplet carbazole‐based transitions in these two Cu I complexes . In addition, the two Cu I complexes are analogous to a Au I complex [Au(Me 2 ‐imy)(cbz)] (Me 2 ‐imy=1,3‐dimethylimidazol‐2‐ylidene, cbz=carbazolate) in literature, which exhibits emission in a high‐energy band (404 nm) and low‐energy band (584 nm) in the crystalline solid.…”

Section: Resultsmentioning

confidence: 68%

Two‐Coordinate Copper(I)/NHC Complexes: Dual Emission Properties and Ultralong Room‐Temperature Phosphorescence

Wang

Zhao

et al. 2020

Angew Chem Int Ed

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As a kind of photoluminescent material, CuI complexes have many advantages such as adjustable emission, variable structures, and low cost, attracting attention in many fields. In this work, two novel two‐coordinate CuI‐N‐heterocyclic carbene complexes were synthesized, and they exhibit unique dual emission properties, fluorescence and phosphorescence. The crystal structure, packing mode, and photophysical properties under different conditions were systematically studied, proving the emissive mechanism to be the locally excited state of the carbazole group. Based on this mechanism, ultralong room‐temperature phosphorescence (RTP) with a lifetime of 140 ms is achieved by selective deuteration of the carbazole group. These results deepen the understanding of the luminescence mechanism and design strategy for two‐coordinate CuI complexes, and prove their potential in applications as ultralong RTP materials.

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Section: Resultsmentioning

confidence: 68%

Two‐Coordinate Copper(I)/NHC Complexes: Dual Emission Properties and Ultralong Room‐Temperature Phosphorescence

Wang

Zhao

et al. 2020

Angew Chem Int Ed

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“…In the 1970s, strong afterglow of triplet‐state emission was observed from salts of a wide variety of polynuclear carboxylic or sulfonic acids, phenols, and amines adsorbed on paper, silica, alumina, and cellulose; the surface adsorption via hydrogen bonding of the ionic phosphor molecules to hydroxyl groups on the support was supposed to be the primary mechanism of providing the rigidity necessary to prevent non‐radiative collisional deactivation of the excited triplet state and restrict oxygen quenching for organic afterglow . Also in the 1970s, Bilen et al reported room temperature emissions with lifetimes up to 4.85 s from solid crystals of carbazole, dibenzothiophene, dibenzofuran, and triphenylene; but, such a long lifetime has not been confirmed by the other investigators. Almost thirty years later, modern research of organic afterglow begins.…”

Section: Introductionmentioning

confidence: 99%

Excited State Modulation for Organic Afterglow: Materials and Applications

et al. 2016

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Organic afterglow materials, developed recently by breaking through the difficulties in modulating ultrafast-decayed excited states, exhibit ultralong-lived emission for persistent luminescence with lifetimes of several orders of magnitude longer than traditional fluorescent and phosphorescent emissions at room temperature. Their exceptional properties, namely ultralong luminescent lifetime, large Stokes shifts, facile excited state transformation, and environmentally sensitive emission, have led to a diverse range of advanced optoelectronic applications. Here, the organic afterglow is reviewed from the perspective of fundamental concepts on both phenomenon and mechanism, examining the technical challenges in relation to excited state tuning and lifetime elongation. In particular, the advances in material design strategies that afford a large variety of organic afterglow materials for a broad utility in optoelectronics including lighting and displays, anti-counterfeiting, optical recording, chemical sensors and bio-imaging are highlighted.

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“…Furthermore, persistent RTP ( p ‐RTP) with naked eye visible emission after ceasing the excitation is even difficult to achieve, despite it has diverse promising applications in advanced OLEDs, bioimaging, encryption and anticounterfeiting ,. So far, increasing examples have been explored in host‐guest systems,, H‐aggregates,,, crystals and even nonconventional luminogens free of aromatics,, the mechanism and rational design strategy, however, remain open questions.…”

Section: Introductionmentioning

confidence: 99%

Pure Organic Persistent Room‐Temperature Phosphorescence at both Crystalline and Amorphous States

Zhang

Wang

et al. 2018

ChemPhysChem

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Persistent room-temperature phosphorescence (p-RTP) of pure organic materials is attracting increasing attention. The design of efficient phosphors and understanding the origin of p-RTP, however, remain challenging. Herein, to gain further insights into pure organic p-RTP, we prepared a group of carbazole (CZ) and methyl benzoate (MBA) conjugates with a methyl ester unit at the para (4-MBACZ), meta (3-MBACZ), and ortho (2-MBACZ) sites. These isomers merely produce prompt fluorescence in solutions, but generate blue prompt/delayed fluorescence (DF) and orange p-RTP with lifetimes up to 865.2 ms in the crystalline state. Lifetimes of p-RTP are in the order of 2-MBACZ>3-MBACZ>4-MBACZ, which might be mainly ascribed to the combined effect of packing density, intermolecular interactions and steric hindrance. Meanwhile, upon mechanical grinding, while the emission color and profile of the luminogens do not significantly change, no (4-MBACZ) or shortened (3-MBACZ, 2-MBACZ) p-RTP is observed, accompanying the change from crystalline to amorphous states. Such p-RTP at amorphous states without external hosts is rarely reported, which demonstrates important implications for the molecular design and mechanism understanding towards p-RTP. Furthermore, their p-RTP attribute and different emission colors before and after ceasing the UV irradiation endow them promising applications in encryption and anticounterfeiting fields.

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Unusual room temperature afterglow in some crystalline organic compounds

Cited by 71 publications

References 4 publications

Two‐Coordinate Copper(I)/NHC Complexes: Dual Emission Properties and Ultralong Room‐Temperature Phosphorescence

Two‐Coordinate Copper(I)/NHC Complexes: Dual Emission Properties and Ultralong Room‐Temperature Phosphorescence

Excited State Modulation for Organic Afterglow: Materials and Applications

Pure Organic Persistent Room‐Temperature Phosphorescence at both Crystalline and Amorphous States

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