Polymer-based room-temperature phosphorescence (RTP) materials with high flexibility and large-area producibility are highly promising for applications in organic electronics. However, achieving such photophysical materials is challenging because of difficulties in populating and stabilizing susceptible triplet excited states at room temperature. Herein large-area, flexible, transparent, and long-lived RTP systems prepared by doping rationally selected organic chromophores in a poly­(vinyl alcohol) (PVA) matrix were realized through a hydrogen-bonding and coassembly strategy. In particular, the 3,6-diphenyl-9H-carbazole (DPCz)-doped PVA film shows long-lived phosphorescence emission (up to 2044.86 ms) and a remarkable duration of afterglow (over 20 s) under ambient conditions. Meanwhile, the 7H-dibenzo­[c,g]­carbazole (DBCz)-doped PVA film exhibits high absolute luminance of 158.4 mcd m2 after the ultraviolet excitation source is removed. The RTP results not only from suppressing the nonradiative decay by abundant hydrogen-bonding interactions in the PVA matrix but also from minimizing the energy gap (ΔE ST) between the singlet state and the triplet state through the coassembly effect. On account of the outstanding mechanical properties and the afterglow performance of these RTP materials, they were applied in the fabrication of flexible 3D objects with repeatable folding and curling properties. Importantly, the multichannel afterglow light-emitting diode arrays were established under ambient conditions. The present long-lived phosphorescent systems demonstrate a bright opportunity for the production of large-area, flexible, and transparent emitting materials.

Long‐lived room temperature phosphorescence (RTP) materials are widely utilized in the field of biological and chemical sensing, due to their unique characteristics of long‐lived luminescence and no background autofluorescence. However, the realization of full‐color RTP in aqueous solution still remains a great challenge. Herein, a feasible strategy for achieving high stability and full‐color RTP of carbon dots (CDs)‐based composite materials in aqueous environment is reported by constructing a rigid hydrogen bonds’ network. The obtained m,p‐CDs@CA composite materials exhibit deep‐blue RTP with phosphorescence quantum yield of 23.2% and lifetime of 1.74 s, and the afterglow can last for over 12 s. More importantly, the m,p‐CDs@CA composite materials are desirable in the detection of biomarkers, because of excellent stability, dispersion, and long‐lived RTP properties. The m,p‐CDs@CA suspension also displays excellent sensitivity, and a limitation of detection as low as 5.61 and 550 nm for biomarkers 5‐hydroxyindole‐3‐acetic acid (HIAA) and serotonin (5‐hydroxytryptamine, HT), respectively. Meanwhile, the sensing performance exhibits excellent selectivity even in the presence of other competitive species in blood plasma and urine. With superior selectivity, the long‐lived phosphorescence probe based on m,p‐CDs@CA suspension can be as an effective biomarker for carcinoid identification, which has potential application in clinical analysis.

Organic room temperature phosphorescence (RTP) materials have drawn increasing attention due to their unique features, especially the long emission lifetime for applications in biomedicine. In this review, we provide an overview of the recent developments of organic RTP materials applied in the biomedicine field. First, we introduce the basic mechanism of phosphorescence and subsequently we present various strategies of modulating the lifetime and efficiency of room temperature organic phosphorescence. Next, we summarize the progress of organic RTP materials in biological applications, including bioimaging, anti‐cancer and antibacterial therapies. Finally, we provide an outlook with regard to the challenges and future perspectives in the field.

Long‐lived room temperature phosphorescence (RTP) systems have become a research focus in the field of functional materials due to their fascinating luminescence properties. However, it is still an enormous challenge to realize RTP under ambient conditions, since RTP can be quenched easily by molecular oxygen. Herein, two polymer acceptors containing triphenyl phosphonium bromide salt are designed and synthesized successfully. They are then doped into a poly(methyl methacrylate) matrix with donor molecules to form flexible films with long‐lived RTP. Interestingly, the long‐lived RTP performance is highly dependent on the grafting rate of the polymers. Upon increasing the grafting rate, the aggregation degree of polymer acceptors increases, further inhibiting the molecular movement in the aggregates and reducing nonradiative vibration deactivation of triplet excitons for achieving green long‐lived RTP. Meanwhile, the visualization of real information and complete pattern after 365 nm UV irradiation is demonstrated based on these long‐lived RTP systems, presenting application potential toward dynamic multilevel information encryption and display devices. This work provides an innovative principle for the activation of long‐lived RTP in the polymeric systems under ambient conditions.

attractive applications in organic lightemitting diodes (OLEDs), [2] high-sensitivity chemical sensing, [3,4] space/time-resolved information encryption, [5] high-resolution biological imaging, [6] optical recording, [7] and so forth. [8] Currently, high-efficiency and long-lived RTP materials are primarily limited to inorganic and metal-containing compounds. In particular, the intrinsic disadvantages of metal resources, such as their high cost and complex preparation processes, predominantly hinder their diverse range of applications. [9] Pure organic RTP materials have received considerable attention owing to their superior performance in terms of affordability, adequate biocompatibility, facile modification of functional groups, simple synthesis, and unique features of flexibility, elasticity, and transparency. [10] However, the phosphorescence process initiating from the lowest excited singlet state (S 1 ) to the triplet state (T) through intersystem crossing (ISC), and thereafter, the generated triplet excited state (T 1 ) to the ground state (S 0 ), is spin forbidden. [11] Moreover, the excited triplet state is readily deactivated by nonradiative vibrations and quenched with molecular oxygen. Therefore, the realization of long-lived RTP under atmospheric conditions at room temperature remains a considerable challenge, even in aqueous environments.In recent years, several effective strategies have been employed to improve the spin-orbit coupling (SOC) and suppress the nonradiative decay. For instance, the introduction of heteroatoms such as N, O, S, or aromatic carbonyl groups into organic systems is beneficial for promoting ISC. [12] Furthermore, crystallization, [13,14] host-guest interactions, [15] polymerization, [16] charge separation, [17] and organic-doped inorganic systems [18,19] have been utilized to minimize nonradiative deactivation and stabilize triplet excitons. Ma et al. [20] employed binary copolymerization of diallyl terephthalate and acrylamide to develop amorphous pure organic polymer materials with a phosphorescence lifetime of 537 ms. Yan et al. [21] developed a new smart RTP film that exhibited direct white-light-emitting polarized phosphorescence. The geometric confinement effect and abundant intermolecular hydrogen bonding between the Room-temperature phosphorescence (RTP) materials have garnered considerable research attention owing to their excellent luminescence properties and potential application prospects in anti-counterfeiting, information storage, and optoelectronics. However, several RTP systems are extremely sensitive to humidity, and consequently, the realization of long-lived RTP in water remains a formidable challenge. Herein, a feasible and effective strategy is presented to achieve long-lived polymeric RTP systems, even in an aqueous environment, through doping of synthesized polymeric phosphor PBHDB into a poly(methyl methacrylate) (PMMA) matrix. Compared to the precursor polymer PBN and organic molecule HDBP, a more rigid polymer microenvironment and electrostatic int...

Long-lived room temperature phosphorescence (RTP) materials are promising for applications in various fields including security information, medical diagnostics, and molecular imaging because of their unique optical properties. Previous RTP materials are mainly excited by ultraviolet light, while synthesizing long-lived RTP materials with visible-light-excitation remains a challenge. In particular, long-lived RTP materials that can be excited by green light are rare. Herein, a feasible and concise chemical strategy for constructing hydrogen-bonded frameworks in an aqueous environment is developed to fabricate large-size, green-light-excited, and excitation-dependent long-lived RTP carbon dot crystals (m,p/CDs-ME). The RTP performance of the crystals exhibits strong excitation wavelength dependence, leading to a full range of visible-light tuning from blue to red. Importantly, the maximum excitation wavelength of the RTP crystals is around 500 nm, thus successfully realizing green light excitation. m,p/CDs-ME presents long-lived phosphorescence (130 ms) under 500 nm excitation in aqueous solution, making it highly suitable for dopamine detection. This work not only provides a general guideline for the development of large size long-lived RTP crystals but also extends the operation scope of long-lived RTP materials in the detection of biomarkers by visible light excitation.

Radical cations of nucleobases are key intermediates causing genome mutation, among which cytosine C•+ is of growing importance because the ensuing cytosine oxidation causes GC → AT transversions in DNA replication. Although the chemistry and biology of steady-state C oxidation products have been characterized, time-resolved study of initial degradation pathways of C•+ is still at the preliminary stage. Herein, we choose i-motif, a unique C-quadruplex structure composed of hemiprotonated base pairs C­(H)+:C, to examine C•+ degradation in a DNA surrounding without interference of G bases. Comprehensive time-resolved spectroscopy were performed to track C•+ dynamics in i-motif and in free base dC. The competing pathways of deprotonation (1.4 × 107 s–1), tautomerization (8.8 × 104 s–1), and hydration (5.3 × 103 s–1) are differentiated, and their rate constants are determined for the first time, underlining the strong reactivity of C•+. Distinct pathway is observed in i-motif compared with dC, showing the prominent features of C•+ hydration forming C­(5OH)• and C­(6OH)•. By further experiments of pH-dependence, comparison with single strand, and with Ag+ mediated i-motif, the mechanisms of C•+ degradation in i-motif are disclosed. The hydrogen-bonding within C­(H)+:C plays a significant role in guiding the reaction flux, by blocking the tautomerization of C­(−H)• and reversing the equilibrium from C­(−H)• to C•+. The C radicals in i-motif thus retain more cation character, and are mainly subject to hydration leading to lesion products that can induce disruption of i-motif structure and affect its critical roles in gene-regulation.

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