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Herein we employ density functional theory (DFT) and linear response time-dependent density functional theory (LR-TDDFT) together with our own n-layered integrated molecular orbital and molecular mechanics (ONIOM)-based quantum mechanical/molecular mechanics (QM/MM) methods to study the room-temperature phosphorescent (RTP) micro-mechanism of several benzonitrile-carbazole (CzBz-X) molecules (i.e. CzBz-H, CzBz-F, CzBz-Cl, CzBz-Br) in liquid and solid state. Based on the calculated the ground- and excited-state geometric and electronic structures, the absorption and emission spectra are simulated and agreed well with previous experimental observation. The intersystem crossing (ISC) rate constants of S1 -> T1 obtained by the formula derived from the Fermi golden rule are small in liquid state, while the ISC rate constants are comparable to the relative radiative rate constants of S1 ->S0 in solid state. Molecular vibrations are restricted in solid state, which lead to the decrease of reorganization energies and Huang-Rhys factors, and the increase of ISC rate constants. Both the heavy-atom effect and aggregation effect play important roles in improving the RTP performance in CzBz-X compounds. Through quantum chemistry calculations, the present work not only elucidates the RTP mechanism and the significance of heavy-atom and aggregation effects in CzBz-X, but also provides new insights for designing novel RTP materials.

Recently, purely organic room-temperature phosphorescence (RTP) from guest-host-doped systems has grown exponentially due to their high modulation flexibility. Benzophenone has been found as a preferred host matrix thanks to its low melting point, minimal biological toxicity, remarkable stability, and cost-effectiveness. However, the precise role of benzophenone remains elusive and has been debated within the scientific community concerning mechanistic elucidations. Here, five indole derivatives were designed and synthesized as guest molecules while retaining benzophenone as the host to construct doped materials exhibiting outstanding RTP properties. Our experimental findings unequivocally establish that the host benzophenone initially absorbs excitation energy, subsequently intersystem crossing into triplet exciton, facilitating the exciton transfer to guest molecule through the triplet energy transfer and culminating in guest RTP emission. Mechanistic investigation corroborates the superiority of benzophenone in possessing a large spin-orbit coupling constant and quantitatively triplet energy transfer. Collectively, this work provides compelling evidence deciphering energy transfer between host and guest entities for the manifestation of phosphorescence performance in benzophenone-hosted doped materials.

A bromophenylpyridine derivative (N1) was designed, synthesized, and the molecule was incorporated into the cavity of the cucurbit[8]uril (Q[8]) as a guest to form a 2:1 host-guest complex. This complex demonstrates good room temperature phosphorescence (RTP) properties in aqueous solution. The host-guest interaction and optical properties of N1@Q[8] in aqueous solution were studied by means of 1 H NMR, ultraviolet-visible absorption spectroscopy, fluorescence spectroscopy, phosphorescence spectroscopy, scanning electron microscopy and inverted fluorescence microscopy. The results show that the bromophenyl part of the guest molecule enters the cavity of Q[8], while the other part of N1 remains outside the cavity, resulting in a 2:1 supramolecular structure. This assembly exhibits specific recognition of dazomet on the phosphorescence spectrum with a detection limit of 8.8329 × 10 -7  mol·L -1 . Collectively, this finding opens up a new possibility for the potential application of room temperature phosphorescent materials in analytical detection., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2025. Published by Elsevier B.V.)

Summary: Room-temperature phosphorescence (RTP) has received extensive attention in recent years due to its various potential applications. Pure organic RTP materials may overcome the shortcomings of harsh preparation conditions and high toxicity associated with metal complexes and rare-earth-containing materials. Although crystallization strategies can yield rigid environments isolated from oxygen, its inferior processability can significantly limit the corresponding practical applications. Considering their flexibility, stretchability, processability, and thermal stability with flexible long chains and intertwined structures, polymers are an ideal material for achieving RTP and realizing practical applications. In this review, we summarize the latest progress in polymer-based RTP materials, elaborating on two strategies of chemical bonding and physical blending. In the last part of the review, challenges and perspectives of amorphous polymers are proposed to improve RTP performance and develop new applications.

To explore the intrinsic mechanism of pure organic room temperature and clustering-induced phosphorescence and investigate mechanochromism and structural-function relationships, here, 4-(2-(9H-carbazol-9-yl)phenyl)-2-amino-6-methoxypyridine-3,5-dicarbonitrile (Lo-CzAD), 4-(3-(9H-carbazol-9-yl)phenyl)-2-amino-6-methoxypyridine-3,5-dicarbonitrile (Lm-CzAD), and 4-(4-(9H-carbazol-9-yl)phenyl)-2-amino-6-methoxypyridine-3,5-dicarbonitrile (Lp-CzAD) were designed and synthesized by choosing self-made carbazole and 3, 5-dicyanopyridine (DCP) unit as electron acceptor and electron donor in sequence. Compared with crystals Lm-CzAD and Lp-CzAD, crystal Lo-CzAD shows better room temperature phosphorescence (RTP) performance, with RTP lifetimes of 187.16 ms, as well as afterglows 1s, which are attributed to twisted carbazole unit and donor-acceptor (D-A) molecular conformation, big crystal density and spin orbit coupling constant ξ (S 1  → T 1 and S 1  → T 2 ), as well as intermolecular H type stacking and small ξ (S 0  → T 1 ). By choosing urea and PPh 3 as host materials and tuning doping ratio, four doping systems were successfully constructed, significantly improving RTP performance of Lo-CzAD and Lp-CzAD, as well as showing different fluorescence and RTP. The lifetimes and afterglows of pure organic Urea/Lo-CzAD and Urea/Lp-CzAD systems are up to 478.42 ms, 5 s, 261.66 ms and 4.5 s in turn. Moreover, Lo-CzAD and Lp-CzAD show time-dependent RTP in doping systems due to monomer and aggregate dispersion, as well as clustering-induced phosphorescence. Based on the different luminescent properties, multiple information encryptions were successfully constructed., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Summary: The transfer of molecular machine technology into aggregated states is a key step for the realization of many potential applications. Here we report three organic luminescent agents, CzS-o-py, CzS-m-py, and CzS-p-py, that can adjust organic room-temperature phosphorescence (RTP) via orderly stimulus-responsive molecular motion in the crystal. Careful analysis of the single-crystal structure before and after ordered molecular motion, coupled with theoretical calculations, reveals the effective intermolecular charge transfer generated by the dense packing mode to be responsible for the RTP effect. Accordingly, a dual anti-counterfeiting application is successfully implemented, exploiting the RTP effect of the stimulus response. The introduction of molecular mechanical technology may provide a strategy for the molecular design, internal mechanism exploration, and practical application of RTP luminescent agents.

Purely organic materials with dual room temperature phosphorescence (RTP) phenomenon were reported recently, but the underlying mechanism was still ambiguous. Herein, we revealed the source of dual RTP emission, taking CzDPS crystal as prototype, by using hybrid quantum mechanics and molecular mechanics (QM/MM) coupled with the thermal vibration correlation function rate theory. Theoretical calculations verified that the emission lifetimes are prolonged from 70 ms in the higher triplet state T 2 to 216 ms in the lowest triplet state T 1 , which is well consistent with the increase of RTP lifetimes from 74 ms for the peak at 465 nm to 627 ms for the band at 565 nm. This is because the radiative and nonradiative decay rates are larger for T 2  → S 0 than that of T 1  → S 0 , which was mainly contributed by the synergistic effect of the increase of spin-orbit coupling and excitation energy, as well as the decrease of reorganization energy. Moreover, the simulated RTP spectra agree well with the experimental ones, including the emission position and profiles. Therefore, the upper-lying triplet excited states are responsible for the dual RTP in CzDPS crystal. This work could contribute to further understanding on the multiple luminescence of organic aggregates., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Unlike fluorescence, room-temperature phosphorescence (RTP) has never been utilized to monitor the dynamic variation of polymer. In the present study, acrylate-vinylidene chloride (VDC) copolymers were doped with a good RTP molecule, N-hydroxyethyl 4-bromo-1,8-naphthalimide (HBN). During the maturation process, marked RTP-intensity enhancement of HBN was observed due to the crystallinity increase of copolymers, verified by X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). For ensuring the more efficient RTP emission of HBN, copolymers with a higher content of crystallizable VDC segments and a more polar acrylate comonomer, i.e. methyl acrylate (MA) were preferred. According to the RTP characterizations, the following deductions could be obtained: (1) Maturation for 8-9 days at room temperature was needed for the copolymers with a high VDC content to ensure the complete crystallization; (2) Raising the maturation temperature to 50 and 70 °C not only accelerated the crystallization rate, but also increased the crystallinity of copolymers; (3) RTP method was more sensitive to the slight crystallinity variation than XRD and FTIR. Moreover, the dynamic maturation processes of acrylate-VDC copolymers could be also visually monitored through contacting with certain organic solvents that led to the emission color transition from orange to blue., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The room-temperature phosphorescence (RTP) of glutathione-capped Mn-doped ZnS quantum dots (GSH-Mn-ZnS QDs) was effectively quenched by the addition of Pb(2+). A simple and sensitive RTP sensor for Pb(2+) detection based on the quenching effect was developed. Under the optimal conditions, good linear correlations were obtained for Pb(2+) over a concentration range from 1.0 to 100μg·L(-1), and the detection limit was 0.45μg·L(-1). The established method has been successfully applied for the determination of Pb(2+) in real water samples without complicated sample pretreatment with the recoveries in the range of 95.4%-104.0%., (Copyright © 2016. Published by Elsevier B.V.)

Quantum dot (QD) nanohybrids provide an effective route to explore the new properties of materials and are increasingly used as highly valuable sensitive (bio) chemical probes. Interestingly, the room-temperature phosphorescence (RTP) of 3-mercaptopropionic acid (MPA)-capped Mn-doped ZnS QDs could be remarkably enhanced by the addition of protamine. Based on the above finding, a simple, sensitive, and selective method for rapid detection of protamine was successfully designed. With this method, protamine as a cationic peptide interacts electrostatically with MPA-capped Mn-doped ZnS QDs to form MPA-capped Mn-doped ZnS QD/protamine complexes, which leads to the aggregation of QDs and enhances the RTP intensity. Under the optimized conditions, the RTP intensity change was linearly proportional to the concentration of protamine in the range 0.2-3.0 μg ml(-1), and the limit of detection was 0.14 μg ml(-1). The proposed method was successfully applied to detect protamine in protamine sulfate injection and human serum samples with satisfactory results, and the recovery ranged from 96.5 to 105.6%., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Mercaptopropionic acid-capped Mn-doped ZnS quantum dots/ethidium bromide (EB) nanohybrids were constructed for photoinduced electron transfer (PIET) and then used as a room-temperature phosphorescence (RTP) probe for DNA detection. EB could quench the RTP of Mn-doped ZnS QDs by PIET, thereby forming Mn-doped ZnS QDs/EB nanohybrids and storing RTP. Meanwhile, EB could be inserted into DNA and EB could be competitively desorbed from the surface of Mn-doped ZnS QDs by DNA, thereby releasing the RTP of Mn-doped ZnS QDs. Based on this mechanism, a RTP sensor for DNA detection was developed. Under optimal conditions, the detection limit for DNA was 0.045 mg L(-1), the relative standard deviation was 1.7%, and the method linear ranged from 0.2 to 20 mg L(-1). The proposed method was applied to biological fluids, in which satisfactory results were obtained., (Copyright © 2015 Elsevier B.V. All rights reserved.)