High-efficiency blue phosphorescence emission is essential for organic optoelectronic applications. However, synthesizing heavy-atom-free organic systems having high triplet energy levels and ...suppressed non-radiative transitions-key requirements for efficient blue phosphorescence-has proved difficult. Here we demonstrate a simple chemical strategy for achieving high-performance blue phosphors, based on confining isolated chromophores in ionic crystals. Formation of high-density ionic bonds between the cations of ionic crystals and the carboxylic acid groups of the chromophores leads to a segregated molecular arrangement with negligible inter-chromophore interactions. We show that tunable phosphorescence from blue to deep blue with a maximum phosphorescence efficiency of 96.5% can be achieved by varying the charged chromophores and their counterions. Moreover, these phosphorescent materials enable rapid, high-throughput data encryption, fingerprint identification and afterglow display. This work will facilitate the design of high-efficiency blue organic phosphors and extend the domain of organic phosphorescence to new applications.
Materials exhibiting long-lived, persistent luminescence in the visible spectrum are useful for applications in the display, information encryption and bioimaging sectors1–4. Herein, we report the ...development of several organic phosphors that provide colour-tunable, ultra-long organic phosphorescence (UOP). The emission colour can be tuned by varying the excitation wavelength, allowing dynamic colour tuning from the violet to the green part of the visible spectrum. Our experimental data reveal that these organic phosphors can have an ultra-long lifetime of 2.45 s and a maximum phosphorescence efficiency of 31.2%. Furthermore, we demonstrate the applications of colour-tunable UOP for use in a multicolour display and visual sensing of ultraviolet light in the range from 300 to 360 nm. The findings open the opportunity for the development of smart luminescent materials and sensors with dynamically controlled phosphorescence.Organic phosphors with ultra-long lifetimes and an emission colour that can be tuned by the excitation wavelength are reported.
Metal-free organic phosphorescence materials are of imperious demands in optoelectronics and bioelectronics. However, it is still a formidable challenge to develop a material with simultaneous ...efficiency and lifetime enhancement under ambient conditions. In this study, we design and synthesize a new class of high efficient ultralong organic phosphorescence (UOP) materials through self-assembly of melamine and aromatic acids in aqueous media. A supramolecular framework can be formed via multiple intermolecular interactions, building a rigid environment to lock the molecules firmly in a three-dimensional network, which not only effectively limits the nonradiative decay of the triplet excitons but also promotes the intersystem crossing. Thus, the supermolecules we designed synchronously achieve an ultralong emission lifetime of up to 1.91 s and a high phosphorescence quantum efficiency of 24.3% under ambient conditions. To the best of our knowledge, this is the best performance of UOP materials with simultaneous efficiency and lifetime enhancement. Furthermore, it is successfully applied in a barcode identification in darkness. This result not only paves the way toward high efficient UOP materials but also expands their applications.
A new type of materials, organic salts in the crystal state, have ultralong organic phosphorescence (UOP) under ambient conditions. The change of cations (NH4+, Na+, or K+) in these phosphors gives ...access to tunable UOP colors ranging from sky blue to yellow green, along with ultralong emission lifetimes of over 504 ms. Single‐crystal analysis reveals that unique ionic bonding can promote an ordered arrangement of organic salts in crystal state, which then can facilitate molecular aggregation for UOP generation. Additionally, reversible ultralong phosphorescence can be realized through the alternative employment of fuming gases (ammonia and hydrogen chloride), demonstrating its potential as a candidate for visual ammonic or hydrogen chloride gas sensing. The results provide an environmental responsible and practicable synthetic approach to expanding the scope of ultralong organic phosphorescent materials as well as their applications.
Ionic crystals with ultralong organic phosphorescence (UOP) are reported. The change of cations (NH4+, Na+, or K+) in these phosphors gives access to tunable UOP colors ranging from sky blue to yellow green. Additionally, reversible ultralong phosphorescence can be realized through the alternative employment of fuming gases (ammonia and hydrogen chloride), demonstrating its potential as a candidate for visual gas sensing.
Luminogens with colorful ultralong organic phosphorescence (UOP) are in high demand because of various potential applications in optoelectronics. Herein, we report a concise approach to tune UOP ...based on the same chromophores of carbazole and phthalimide units through alkyl engineering. With flexible alkyl increase, UOP emission colors can be controllably tuned from green to orange along with lifetime variation. Furthermore, these phosphors were endowed with unexpected visible-light excitation, mechanochromism, and mechanoluminescence properties simultaneously. Additionally, colorful UOP with diverse emission lifetime was first applied to the 4D code for information encryption. These findings will open a door to explore multifunctional organic phosphorescence materials and expand their potential applications.
A modular approach to azulene building blocks was developed starting from readily available aryl‐substituted cyclopentadiene and ortho‐haloaryl aldehyde by dehydration condensation followed by ...palladium‐catalyzed C−H coupling. It facilitates the synthesis of four nonalternant isomers of pentacene and hexacene, namely, dibenzoe,gazulene, benzo1,2‐f : 5,4‐f′diazulene, benzo1,2‐f : 4,5‐f′diazulene, and naphtho2,3‐f : 6,7‐f′diazulene, which exhibit narrow band gaps with high stability in addition to protonation‐caused enhanced near‐infrared fluorescence. We discovered that in these isomers, i) constitutional isomerism influences significantly their photoelectric properties and ii) the elongation of the conjugation system does not necessarily lead to a narrowing in the band gap. Due to the easy modifiability of the nonazulene building blocks, this strategy can be extended to modularly prepare numerous multiazulene‐fused aromatics.
A modular two‐step 4+3 annulation approach to azulene units was developed starting from readily available aryl‐substituted cyclopentadiene and ortho‐haloaryl aldehyde by dehydration condensation followed by palladium‐catalyzed C−H coupling. It facilitates the syntheses of four nonalternant isomers of pentacene and hexacene including DBA, BDA1, BDA2, and NDA which exhibit narrow band gaps and protonation‐caused enhanced near‐infrared emission.
Ultralong organic phosphorescence (UOP) materials have roused considerable attention in the field of photonics and optoelectronics owing to the feature of long-lived emission lifetimes. However, to ...develop UOP materials with color-tunability is still a formidable challenge. Here, we report a class of UOP materials containing carbonyl, amino or amide groups, exhibiting colortunable persistent luminescence ranging from blue (458 nm) to yellow-green (508 nm) under different UV wavelength excitation. Taken theoretical and experimental results together, we conclude that the excitation dependent color-tunable UOP emission is ascribed to multiple emission centers from single molecular and aggregated states in crystal. Given color-tunable UOP feature, these materials are used to successfully realize visual UV-light detection. This finding not only provides a strategy to design new organic phosphorescent molecules with colorful emission, but also extends the scope of the applications of purely organic phosphorescent materials.
Nonradiative recombination losses originating from crystallographic distortions and issues occurring upon interface formation are detrimental for the photovoltaic performance of perovskite solar ...cells. Herein, we incorporated a series of carbamide molecules (urea, biuret, or triuret) consisting of both Lewis base (-NH
) and Lewis acid (-C=O) groups into the perovskite precursor to simultaneously eliminate the bulk and interface defects. Depending on the different coordination ability with perovskite component, the incorporated molecules can either modify crystallization dynamics allowing for large crystal growth at low temperature (60°C), associate with antisite or undercoordinated ions for defect passivation, or accumulate at the surface as an energy cascade layer to enhance charge transfer, respectively. Synergistic benefits of the above functions can be obtained by rationally optimizing additive combinations in an all-in-one deposition method. As a result, a champion efficiency of 21.6% with prolonged operational stability was achieved in an inverted MAPbI
perovskite solar cell by combining biuret and triuret additives. The simplified all-in-one fabrication procedure, adaptable to different types of perovskites in terms of pure MAPbI
, mixed perovskite, and all-inorganic perovskite, provides a cost-efficient and reproducible way to obtain high-performance inverted perovskite solar cells.
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Regioisomerism effect was disclosed on optimizing ultralongorganic phosphorescence life times of three crystalline dicarbazol-9-yl pyrazine-based regioisomers (p-DCzP, m-DCzP, and ...o-DCzP) with para-, meta-, and ortho-convergent substitutions. It is revealed that regioisomerism effect could be an effective strategy for the deep understanding of UOP materials.
Organic phosphorescence materials demonstrate potential optoelectronic applications due to their remarkably ultralong organic phosphorescence (UOP) lifetime and abundant optical characteristics prior to the fluorescence materials. For a better insight into the intrinsic relationship among regioisomeric molecules, crystalline interactions, and phosphorescence properties, three crystalline dicarbazol-9-yl pyrazine-based regioisomers with para-, meta-, and ortho-convergent substitutions (p-DCzP, m-DCzP, and o-DCzP) were designed and presented gradually increased UOP lifetimes prolonging from 63.14, 127.93 to 350.46 ms, respectively, due to the regioisomerism effect (RIE) which would be an effective strategy for better understanding of structure-property of UOP materials.
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