Room Temperature Phosphorescence: Achieving Amorphous Ultralong Room Temperature Phosphorescence by Coassembling Planar Small Organic Molecules with Polyvinyl Alcohol (Adv. Funct. Mater. 10/2019)

Wu, Hongwei; Chi, Weijie; Chen, Zhao; Li, Guofeng; Gu, Long; Bindra, Anivind Kaur; Yang, Guangbao; Liu, Xiaogang; Zhao, Yanli

doi:10.1002/adfm.201970063

Cited by 22 publications

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“…Due to the inefficient intersystem crossing (ISC) based on weak spin–orbit coupling and the high nonradiative decay rate of the triplet excitons as well as quenching factors like oxygen, different strategies to achieve RTP have been developed in recent years. Among those, host–guest doping, [ 20–23 ] H‐aggregation, [ 10,24–28 ] supramolecular frameworks, [ 24 ] polymers, [ 29–38 ] carbon dots, [ 39–43 ] and small molecules [ 44 ] can be found. In any case, the emitting molecules must be embedded in a rigid environment, be it a crystalline structure or a polymer host, causing a confinement of molecular motion.…”

Section: Figurementioning

confidence: 99%

Aromatic Phosphonates: A Novel Group of Emitters Showing Blue Ultralong Room Temperature Phosphorescence

et al. 2020

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In recent years, there has been a growing interest in purely organic materials showing ultralong room‐temperature phosphorescence with lifetimes in the range of seconds. Still, the longest known phosphorescence lifetimes are only achieved with crystalline systems so far. Here, a rational design of a completely new family of halogen‐free organic luminescent derivatives in amorphous matrices, displaying both conventional fluorescence and phosphorescence is reported. Hydrogen bonding between the newly developed emitters and an ethylene‐vinyl alcohol copolymer (Exceval) matrix, which efficiently suppresses vibrational dissipation, enables bright long‐lived phosphorescence with lifetimes up to 2.6 s at around 480 nm. The importance of the chosen matrix is shown as well as the implementation in an organic programmable luminescent tag.

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Section: Figurementioning

confidence: 99%

Aromatic Phosphonates: A Novel Group of Emitters Showing Blue Ultralong Room Temperature Phosphorescence

et al. 2020

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“…However, OPRTP is rare in pure organic molecules because of the forbidden transition from singlet to triplet excited states. The reported metal‐free OPRTP materials are usually substituted with aromatic carbonyl groups or heavy atoms to facilitate the intersystem crossing (ISC) process, while crystallization, host–guest interaction, and polymer doping are utilized to suppress the nonradiative decay and stabilize the triplet states.…”

Section: Introductionmentioning

confidence: 99%

Achieving Dual Persistent Room‐Temperature Phosphorescence from Polycyclic Luminophores via Inter‐/Intramolecular Charge Transfer

Guo

Qin

et al. 2019

Advanced Optical Materials

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bioimaging, [3] and anti-counterfeiting applications. [4] Pure organic OPRTP materials are more attractive compared to the transition metal or rare earth-based phosphorescent materials owing to their low production cost, easy synthesis, low toxicity, and good flexibility. [5] However, OPRTP is rare in pure organic molecules because of the forbidden transition from singlet to triplet excited states. The reported metal-free OPRTP materials are usually substituted with aromatic carbonyl groups [6] or heavy atoms [7] to facilitate the intersystem crossing (ISC) process, while crystallization, [8] host-guest interaction, [9] and polymer doping [10] are utilized to suppress the nonradiative decay and stabilize the triplet states.Solid-state phosphorescence is highly dependent on molecular stacking, such as aggregation-caused quenching. [11] Recently, OPRTP has been observed in H- [8a] or J-aggregates, [12] while the influence of T-shaped (edge-to-face) arrangement on phosphorescence has been rarely discussed. Published work mainly focused on the stabilization of triplet excited states by molecular packing, but packing-induced intermolecular charge transfer received less attention in OPRTP materials although it strongly affected ISC efficiency and the energy gap (ΔE ST ) between singlet and triplet excited states. [3c,13] Polycyclic π-conjugated compounds, such as indolo[3,2-b] carbazoles (ICZs) and their analogues, are important organic semiconductors, which have been widely used in organic optoelectronic fields, such as organic field-effect transistors and photovoltaic cells, owing to their excellent carrier transporting properties. [14] In this work, 6,12-diphenyl-5,6,11,12tetrahydroindolo[3,2-b]carbazole (Ben-H, Figure 1), one of the ICZ analogues, unexpectedly exhibited OPRTP after the cease of UV light irradiation. Unlike most reported OPRTP materials, there were no commonly used groups such as aromatic carbonyl groups or heavy atoms in Ben-H. Based on the energy level diagram and single-crystal structure of Ben-H, we hypothesized that charge transfer (CT) played a dominant role in persistent emission (Figure 2). In the isolated molecular state, intramolecular charge transfer (ICT) from the indole rings to the benzene rings gave rise to the ISC process with narrow ΔE ST energy gap, while in the dimers, T-shaped CH···π interactions induced Organic persistent room-temperature phosphorescence (OPRTP) materials show great prospects in optoelectronic and biomedical applications, such as display, anti-counterfeiting, sensing, and bioimaging. However, the reported OPRTP material systems are relatively rare, and it is a challenge to achieve the tunability of OPRTP. In this work, a series of polycyclic luminophores are developed based on an indole derivative (6,12-diphenyl-5,6,11,12tetrahydroindolo[3,2-b] carbazole, Ben-H) as the structural skeleton. These compounds unexpectedly exhibit dual OPRTP at 442 to 623 nm with lifetimes spanning from 2 to 759 ms. Experimental data and theoretical calculations suggest th...

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“…These observations indicate the important role of the Pluronic F‐127 amphiphilic triblock copolymers in assisting the regular packing of planar RTP‐8 molecules, when compared to the case of RTP‐8 precipitates. It is noteworthy that crystalline nanostructures with such a well‐defined morphology and regular molecular packing in the present study (Figure 3A–3C) have been rarely reported in purely organic RTP systems [10–35] . Other block copolymers (Scheme 1C) have also been used to assemble with RTP‐8 in aqueous solutions.…”

Section: Resultsmentioning

confidence: 58%

“…The aggregation states of the organic RTP molecules have a large influence on their phosphorescence properties. Most of the reported RTP phenomena in purely organic systems can only be observed in molecular crystalline states where the nonradiative deactivation of the triplet excited states can be effectively suppressed [10–35] . However, the molecular crystals usually lack solution dispersity, [10–39] which limits the applications of these RTP materials.…”

Section: Introductionmentioning

confidence: 99%

Achieving Purely‐Organic Room‐Temperature Aqueous Phosphorescence via a Two‐Component Macromolecular Self‐Assembly Strategy

Guo

Wang

Zhou

et al. 2020

Chemistry An Asian Journal

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Manipulation of supramolecular behaviors and aggregation states represents an important topic in devising intriguing photofunctional systems. Here we report a twocomponent macromolecular self-assembly strategy for achieving aqueous room-temperature phosphorescence (RTP) in purely organic systems. Amphiphilic triblock copolymers are used to modulate the self-assembly of planar RTP molecules in aqueous solution, leading to the formation of sheet-like RTP objects with well-defined morphology, uniform crystalline nanostructures and excellent aqueous dispersity. In contrast, the addition of the planar RTP molecules into aqueous medium only leads to precipitation and quenching of RTP properties. Powder X-ray diffraction and single-crystal X-ray diffraction studies reveal that the amphiphilic triblock copolymers can assist supramolecular columnar packing of the planar RTP molecules where multiple non-covalent interactions stabilize the triplet excited states. Interestingly, it is found that luminescent signals of the sheet-like RTP objects can be extracted from strong fluorescent environments by phosphorescence mode and emission lifetime measurement.

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Room Temperature Phosphorescence: Achieving Amorphous Ultralong Room Temperature Phosphorescence by Coassembling Planar Small Organic Molecules with Polyvinyl Alcohol (Adv. Funct. Mater. 10/2019)

Cited by 22 publications

References 0 publications

Aromatic Phosphonates: A Novel Group of Emitters Showing Blue Ultralong Room Temperature Phosphorescence

Aromatic Phosphonates: A Novel Group of Emitters Showing Blue Ultralong Room Temperature Phosphorescence

Achieving Dual Persistent Room‐Temperature Phosphorescence from Polycyclic Luminophores via Inter‐/Intramolecular Charge Transfer

Achieving Purely‐Organic Room‐Temperature Aqueous Phosphorescence via a Two‐Component Macromolecular Self‐Assembly Strategy

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