Covalent Bonding Enhanced Structural Rigidity for Boosted Heavy Atom-Free Room-Temperature Phosphorescence

New Sensitive and Selective Fluorescent Probes for Fluoride Using Boronic Acids

While room-temperature phosphorescence (RTP) materials have been predominantly realized in solid films, the development of liquid and hydrogel systems that retain ultralong afterglow remains highly desirable. Here, we report a high-solid-content (∼30%) afterglow emulsion system based on an electron-deficient naphthalimide (NI) derivative as the luminescent dopant and a copolymer matrix of methyl methacrylate (MMA) with methyl acrylate (MA), denoted as P(MMA/MA). Although the NI-doped P(MMA/MA) exhibits a much lower glass transition temperature than the PMMA homopolymer, it surprisingly delivers a longer afterglow duration (tag), revealing that matrix rigidity is not the sole determinant of ultralong RTP. Under ambient conditions, the NI-doped P(MMA/MA) emulsion achieves a lifetime of up to 1.95 s (tag ≈ 29 s), while the corresponding solid film exhibits a lifetime of 2.18 s (tag ≈ 34 s), placing both among the top-performing systems in their respective states. Beyond UV excitation, both the emulsion and the film can also be activated using safer 405 nm visible light, yielding tag values of up to 14 s and 16 s, respectively. When blended with poly(vinyl alcohol), the emulsion forms stretchable hydrogels with a tag of ∼20 s, significantly surpassing most reported hydrogel-based RTP materials. Furthermore, through phosphorescence resonance energy transfer, we extend the emission into the red region, producing emulsions with tag exceeding 10 s and demonstrating the spectral tunability of this approach across the green-to-red range. This work provides a versatile strategy for designing multistate RTP materials with long afterglow and good processability, showing promise for applications in bioimaging, sensing, and information encryption.

Organic room-temperature phosphorescence (RTP) materials with large Stokes shifts and prolonged afterglows are gaining increasing attention in a variety of applications, including displays, anti-counterfeiting, sensing, and bioimaging. However, achieving high-performance organic RTP remains challenging due to weak spin-orbit coupling, rapid non-radiative decay, and unstable triplet excitons. Early studies focused on crystal engineering, as ordered lattices restrict molecular motion and stabilize triplet excitons. Analyzing crystal structures and packing provides valuable insights into intermolecular interactions, while theoretical calculations have clarified electronic structures, laying the foundation for rational RTP material design. However, recent findings suggest RTP in many single-component systems may arise from trace impurities, significantly influencing RTP properties. This discovery has greatly advanced the understanding of impurity-induced phosphorescence. This review systematically examines the role of impurities in RTP, detailing their origins from starting materials, solvents, and side reactions. It also explores how these identified impurities can serve as essential building blocks for designing new RTP materials. Finally, essential methods for evaluating compound purity, emphasizing the critical importance of rigorous analysis and validation are presented. Material purity plays a pivotal role in RTP research, as impurities can distort experimental data, potentially leading to misinterpretations that can impede advancements in understanding the underlying mechanisms.

Ultralong sodium alginate-based room temperature phosphorescence materials with advantages of color tunability, flexibility and facile large-area fabrication

Si-assisted N, P Co-doped room temperature phosphorescent carbonized polymer Dots: Information Encryption, graphic Anti-counterfeiting and biological imaging

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.

Polymerization and characterization of the monolayers composed of a boronic acid-carrying diacetylenic compound, m-(10,12-pentacosadiynamide)phenylboronic acid (DA-PBA), have been performed at the air–water interface and on solid substrates. m-(10,12-Pentacosadiynamide)anisole (DA-An), which has a methoxy group in place of the boronic acid group, has also been prepared and used for comparison. DA-PBA formed a stable monolayer on water. Photopolymerization of the monolayer proceeded successfully on water at both 5 and 20 °C and gave a highly conjugated blue polymer with absorption maxima at 600 and 645 nm. The DA-PBA LB film transferred from the surface monolayer onto a quartz plate also provides such a blue polymer upon UV irradiation. This polymerized DA-PBA LB film was found to display completely reversible thermochromism between 20 and 70 °C, and the boronic acid groups located at the surface of the LB film did not interact with poly(vinyl alcohol) at all. Therefore, the spontaneous dehydration among boronic acid groups was supposed to occur, accompanied by polymerization of the diacetylene moiety. The formation of borate glass was supported by FT-IR and XPS spectroscopies.

Purely organic room temperature phosphorescence (RTP) materials have shown broad application prospects in organic light‐emitting diodes (OLEDs) due to their theoretical 100% exciton utilization, cost‐effectiveness, and flexibility. In recent years, with the deepening of research, various luminescent mechanisms have been proposed, and RTP materials have made significant progress, which have been effectively applied to OLEDs. This article comprehensively reviews the research progress of RTP materials in OLEDs and introduces the development of a series of high‐efficiency RTP materials from the perspective of molecular design strategies and photophysical properties. These conclusions draw a roadmap to address the inherent challenges in utilizing organic RTP materials to specifically advance the investigation of OLEDs.

Room temperature phosphorescence (RTP) organic emitters have gained increasing attention in the fields of lighting, security and bioimaging. However, lack of clear mechanism and universal methods of regulating RTP property impeded the further development of RTP materials. Most importantly, the long lifetime and high quantum yield (QY) of RTP can hardly be achieved at the same time. Herein, we report a molecular design strategy to improve both lifetime and QY of RTP through intramolecular interaction. The enhancement of lifetime and QY were up to one order, respectively by introducing S···O noncovalent intramolecular interactions into the molecule. The X-ray single crystal analysis and theoretical calculations were performed together to give the solid evidence that the intramolecular interaction can not only suppress the nonradiative transition but also stabilize the triple states. This study provided a novel idea of developing high-performance RTP materials.

Boronic acid conjugated polyacrylate coating: A strategy for material-independent surface functionalization

Pure organic room temperature phosphorescence (RTP) materials are considered as potential candidates for replacing precious metal-based complexes to fabricate highly efficient organic light emitting devices (OLEDs). However, for reported RTP materials, low photoluminescence quantum yields (PLQYs) in thin film state seriously impede their applications in OLEDs. On the other hand, how using normal organic fluorescence materials to fabricate OLEDs with an internal quantum efficiency (IQE) over 25% remains a great unaddressed issue beyond the thermally activated delayed fluorescence (TADF) sensitization approach. Here, we establish a strategy to construct highly efficient OLEDs based on pure organic RTP material sensitized fluorescence emitter. The key point for our strategy is that benzimidazole-triazine molecules (PIM-TRZ), 2,6-di(phenothiazinyl)naphthalene (β-DPTZN) and 5,6,11,12-tetraphenylnaphthacene (rubrene) were screened as host, phosphor sensitizer and fluorescent emitter, respectively. Detail photophysical characterizations demonstrate that the host material PIMTRZ with unique RTP nature is critical for achieving phosphor sensitizing process. As an organic RTP compound, the singlet and triplet state energy levels of β-DPTZN perfectly match with those of PIMTRZ, resulting in the formation and lasting existence of phosphor’s excitons in emitting layer. The large overlap between the absorption spectrum of rubrene and PL spectrum of PIM-TRZ:10% β-DPTZN film can facilitate the Förster energy transfer from the triplet β-DPTZN to the singlet rubrene and the finally displayed fluorescence is derived from singlet excited states of rubrene. The perfect collocation of host, phosphorescent sensitizer and fluorescent emitter in the emitting layer promise the predominant performance of the devices with external quantum efficiency (EQE) of 15.7%. The PLQY of emitting layer is 60.3%, and therefore about 90% carrier injection induced excitons are harvested for light emission. We present a new strategy to fabricate efficient fluorescent devices by employing ingenious combination of host, phosphorescent sensitizer and fluorescent emitter, which is significant to the development of OLEDs.

A novel polymer complex system sensitive to glucose was studied as a candidate material for formulating a chemically regulated insulin release system. A ternary copolymer of N‐vinyl‐2‐pyrrolidone (NVP), 3‐acrylamidophenylboronic acid (AAm‐PBA) and N,N‐dimethylaminopropylacrylamide (DMAPAA) (poly(NVP‐co‐PBA‐co‐DMAPAA)) was synthesized by radical copolymerization. The phenylboronic acid group in this copolymer serves as a glucose sensor moiety. Poly(NVP‐co‐PBA‐co‐DMAPAA) was soluble in water in the pH range of 3–12, in sharp contrast to a binary copolymer of NVP and AAm‐PBA (poly(NVP‐co‐PBA)) which showed solubility only under alkaline aqueous conditions, where the boronic acid group is in a tetrahedral ionized form. The protonated amino group in poly(NVP‐co‐PBA‐DMAPAA) contributed to increase the solubility of the polymer under physiological and acidic aqueous conditions. Furthermore, poly(NVP‐co‐PBA‐co‐DMAPAA) formed a stable polymer complex gel with poly(vinyl alcohol) (PVA) in pH 7.4 phosphate buffered solution due to the formation of a covalent linkage between the boronic acid groups in ternary copolymer and diol units in PVA. The release of myoglobin as model protein from the complex gel was increased immediately after the addition of glucose, due to the transition of gel into sol state, indicating the feasibility of this complex gel as a candidate material for a glucose‐responsive delivery system for insulin.

Designing ultralong‐lived aqueous room temperature phosphorescence (RTP) materials has become an actively pursued but challenging research area. Herein, a coordination‐induced structural rigidity (CISR) strategy is proposed to achieve ultralong RTP lifetime in magnesium/pyromellitic acid phosphorescent materials (Mg/PMA‐PMs) with abundant Mg2+ ions sites and hydrophilic groups in aqueous solution. Compared to their dry state (448.77 ms), the lifetime of Mg/PMA‐PMs significantly increases to 1026.17 ms with the addition of a small amount of water (50 wt%). Even in a fully non‐deoxygenated aqueous environment (above 200 wt% water), where Mg/PMA‐PMs disintegrate to form a nanosuspension, they still exhibit an ultralong aqueous RTP lifetime of ≈800 ms. The water‐enhanced RTP properties are attributed to water molecules coordinating with Mg2+ ions and acting as bridging agents to bind with hydrophilic groups through hydrogen bonding. This interaction rigidifies functional groups and inhibits their motions, leading to a substantial reduction in nonradiative decay. Furthermore, the CISR mechanism effectively explains the RTP enhancement effect of water on inorganic salt phosphorescent systems. This work not only provides a new approach for constructing efficient aqueous RTP materials, but also develops a powerful tool for visual anion recognition.

Boron chemistry at the millennium

With the aid of D‐glyceric acid as a template, an amino‐ and a boronic acid group, respectively, were introduced in a defined steric arrangement into polymers. For this, the monomer D‐N‐(4‐vinylphenyl)carbamoylethylenedioxy(4‐vinylphenyl)borane (1) was copolymerized into macroporous polymers under various conditions. The template D‐glyceric acid was split off from the polymer with 20% HCl in methanol. The specificity of the polymers obtained with one amino‐ and one boronic acid group, respectively, per cavity was derived from their ability to resolve racemic glyceric acid. Racemic resolution was also observed on equilibration of the polymers with D,L‐methyl glycerate and D,L‐glyceraldehyde.