Search

Intercalated layered materials offer distinctive properties and serve as precursors for important two-dimensional (2D) materials. However, intercalation of non-van der Waals structures, which can expand the family of 2D materials, is difficult. We report a structural editing protocol for layered carbides (MAX phases) and their 2D derivatives (MXenes). Gap-opening and species-intercalating stages were respectively mediated by chemical scissors and intercalants, which created a large family of MAX phases with unconventional elements and structures, as well as MXenes with versatile terminals. The removal of terminals in MXenes with metal scissors and then the stitching of 2D carbide nanosheets with atom intercalation leads to the reconstruction of MAX phases and a family of metal-intercalated 2D carbides, both of which may drive advances in fields ranging from energy to printed electronics. Funding Agencies|Key R&D Projects of Zhejiang Province; Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang; International Partnership Program of Chinese Academy of Sciences [2022C01236]; Advanced Energy Science and Technology Guangdong Laboratory [2019R01003]; Ningbo Top-talent Team Program [174433KYSB20190019]; Ningbo "3315 plan" [HND20TDTHGC00]; National Natural Science Foundation of China; China Postdoctoral Science Foundation [2018A-03-A]; Knut and Alice Wallenberg Foundation through the Wallenberg Academy Fellows Program [21671195, 52172254, 52250005, 52202325, U2004212]; Wallenberg Scholar Program [2020M680082]; Swedish National Infrastructure in Advanced Electron Microscopy [KAW 2020.0196]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoeping University SFO-Mat-LiU [KAW 2019.0290]; US National Science Foundation [2021-00171, RIF21-0026]; [2009 00971]; [DMR-2041050]

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. This work was financially supported by the National Natural Science Foundation of China (21875025), the Innovation Research Group at Institutions of Higher Education in Chongqing (CXQT19027), the Science and Technology Research Program of Chongqing Municipal Education Commission (KJZD-K201801101), the Chongqing Talent Program, the Science and Technology Project of Banan District, and the Innovation Support Plan for the Returned Overseas of Chongqing (cx2020052).

Long-lived organic room-temperature phosphorescence (RTP) has sparked intense explorations, owing to the outstanding optical performance and exceptional applications. Because triplet excitons in organic RTP experience multifarious relaxation processes resulting from their high sensitivity, spin multiplicity, inevitable nonradiative decay, and external quenchers, boosting RTP performance by the modulated triplet-exciton behavior is challenging. Herein, we report that cross-linked polyphosphazene nanospheres can effectively promote long-lived organic RTP. Through molecular engineering, multiple carbonyl groups (C═O), heteroatoms (N and P), and heavy atoms (Cl) are introduced into the polyphosphazene nanospheres, largely strengthening the spin-orbit coupling constant by recalibrating the electronic configurations between singlet (Sn) and triplet (Tn) excitons. In order to further suppress nonradiative decay and avoid quenching under ambient conditions, polyphosphazene nanospheres are encapsulated with poly(vinyl alcohol) matrix, thus synchronously prompting phosphorescence lifetime (173 ms longer), phosphorescence efficiency (∼12-fold higher), afterglow duration time (more than 20 s), and afterglow absolute luminance (∼19-fold higher) as compared with the 2,3,6,7,10,11-hexahydroxytriphenylene precursor. By measuring the emission intensity of the phosphorescence, an effective probe based on the nanospheres is developed for visible, quantitative, and expeditious detection of volatile organic compounds. More significantly, the obtained films show high selectivity and robustness for anisole detection (7.1 × 10-4 mol L-1). This work not only demonstrates a way toward boosting the efficiency of RTP materials but also provides a new avenue to apply RTP materials in feasible detection applications. Ministry of Education (MOE) This work was financially supported by the National Natural Science Foundation of China (21875025), the Innovation Research Group at Institutions of Higher Education in Chongqing (CXQT19027), the Chongqing Talent Program, the Science and Technology Project of Banan District, the Innovation Support Plan for the Returned Overseas of Chongqing (cx2020052), and the Open Fund of Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates (2021-kllma-03). The research was also supported by the Singapore Ministry of Education Academic Research Funds (RG3/21 and MOET2EP10120-0003).

Novel barium strontium titanate@silver (BST@Ag) hybrid particles with controllable Ag content are fabricated through the surface grafting modification combined with an in situ reduction of Ag+, using (3-mercaptopropyl)trimethoxysilane (MPTMS) as a surface-grafting agent. The surface character of BST nanoparticles changes from initially hydrophilic to lipophilic upon grafting of MPTMS. Polymer composites are then prepared by dispersing the BST@Ag hybrid particles in poly(aryl ether nitrile) (PAEN). Benefiting from improved compatibility and dispersibility between modified particle fillers and the polymer matrix, the BST@Ag/PAEN composites exhibit enhanced dielectric properties, including significantly increased dielectric permittivity, relatively low dielectric loss, and good permittivity-temperature stability below 140 °C. The composites also demonstrate excellent thermal stability and high mechanical strength, offering attractive prospects as high-temperature-resistant dielectric materials for use in various engineering applications.

Long-lived organic room-temperature phosphorescent (RTP) materials have attracted widespread attention because of their fantastic properties and application prospects. The current methods for developing RTP materials are mainly based on the synthesis of new chromophore molecules and crystallization engineering. However, there are great challenges in the preparation of new chromophore molecules and the use of crystalline materials. Herein, dynamic stimulus-responsive long-lived RTP systems with various emission colors are realized by doping organic chromophore molecules into polymer matrix prepared from vinyl acetate and acrylic acid. Through UV light irradiation, the growth process of long-lived RTP phenomena can be observed for up to 10 s. In particular, the phosphorescence intensity, lifetime, afterglow brightness, and quantum yield of one representative film (P2-M2) increase by 155, 262, 414, and 8 times after the irradiation, respectively. The unique photophysical phenomena are ascribed to the oxygen consumption characteristics of the polymer matrix under UV irradiation. Meanwhile, the information storage devices are prepared with these RTP systems. This work provides a strategy for achieving small organic molecule-doped polymer RTP systems that are easy to prepare, low-cost, and widely adaptable. Ministry of Education (MOE) This work was financially supported by the National Natural Science Foundation of China (21875025), the Special Program of Chongqing Science and Technology Commission (cstc2018jcyjAX0296), the Innovation Research Group at the Institutions of Higher Education in Chongqing (CXQT19027), the Science and Technology Research Program of Chongqing Municipal Education Commission (KJZD-K201801101), Chongqing Talent Program, the Science and Technology Project of Banan District, and the Innovation Support Plan for the Returned Overseas of Chongqing (cx2020052). The research was also supported by Singapore Academic Research Fund (RT12/19 and MOE-MOET2EP10120-0003).

Polyethylene (PE) and polyethylene glycol (PEG) with three different molecular weights are employed to modify bitumen, which is denoted as the polymer-modified bitumen (PMB). The samples, PMB-L, PM...

Room temperature phosphorescence (RTP) has drawn extensive attention in recent years. Efficient stimulus-responsive phosphorescent organic materials are attractive, but are extremely rare because of unclear design principles and intrinsically spin-forbidden intersystem crossing. Herein, we present a feasible and facile strategy to achieve ultraviolet irradiation-responsive ultralong RTP (IRRTP) of some simple organic phosphors by doping into amorphous poly(vinyl alcohol) matrix. In addition to the observed green and yellow afterglow emission with distinct irradiation-enhanced phosphorescence, the phosphorescence lifetime can be tuned by varying the irradiation period of 254 nm light. Significantly, the dynamic phosphorescence lifetime could be increased 14.3 folds from 58.03 ms to 828.81 ms in one of the obtained hybrid films after irradiation for 45 min under ambient conditions. As such, the application in polychromatic screen printing and multilevel information encryption is demonstrated. The extraordinary IRRTP in the amorphous state endows these systems with a highly promising potential for smart flexible luminescent materials and sensors with dynamically controlled phosphorescence., Efficient stimulus-responsive phosphorescence organic materials are attractive, but are extremely rare because of unclear design principles and intrinsically spin-forbidden intersystem crossing. Here, the authors present a facile strategy to achieve ultraviolet irradiation-responsive ultralong room-temperature phosphorescence in several simple amorphous polymer materials.

Materials exhibiting ultralong luminescent lifetime show promising applications in the fields of information encryption, sensing, and bioimaging. Herein, we present a low-cost and general strategy to achieve stimulus-responsive ultralong organic phosphorescence (UOP) based on pyrene chromophores doped into polymer matrices. The UOP of the resulted systems presents radiation-, concentration-, time-, and excitation-dependent characteristics. The UOP color can be turned from blue to red by changing the excitation wavelength or the concentration of chromophores. Experimental results prove that these characteristics are attributed to the consumption of triplet oxygen and the different aggregation states of chromophores in the polymer matrices. Finally, we demonstrate that these systems could be applied for multilevel information encryption. This work would promote further development of multi-responsive long-lived luminescent materials. This work was financially supported by the National Natural Science Foundation of China (21875025), the Innovation Research Group at Institutions of Higher Education in Chongqing (CXQT19027), the Chongqing Talent Program, the Science and Technology Project of Banan District, the Innovation Support Plan for the Returned Overseas of Chongqing (cx2020052), and the Open Fund of Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates (2021-kllma-03).

With the application of hot-pressing technology, polyamide 6 (PA6) was successfully directly adhered to the aluminum alloy. The relationship between the bonding property and microstructures of PA6 and anodized AA5754 aluminum alloy hybrid were explored in the paper. The results showed that the honeycomb-like porous oxide film was prepared by anodic oxidation, which resulted in the decreased surface energy of the aluminum alloy, so that PA6 easily wetted on the aluminum alloy surface, and the maximum tensile shear strength and fracture work reached 8.24 MPa and 9.27 kJ m−2, respectively. Improved bonding strength was attributed to micro- and nanoscale honeycomb-like microstructures and large roughness on the anodized aluminum alloy surface.

Long-lived room temperature organic phosphorescence is highly useful in biological imaging, electroluminescent devices, information security, and security protection on account of its unique photophysical process and long-lived luminescence. In recent years, pure organic phosphorescent materials that do not contain rare precious metals have received increasing attention. Carbazole and its derivatives have been used to develop room temperature organic phosphorescent materials. However, the effect of carbazolyl groups on the photophysical properties of pure organic phosphors has rarely been reported. In this work, three cyanuric chloride phosphors (CzDCIT, BiCzDT, and TCzT) modified with different numbers of carbazolyl groups were synthesized. Several characterization techniques were employed to reveal distinct crystal forms of CzDCIT, BiCzDT, and TCzT. The single crystal diffraction of CzDCIT and BiCzDT showed not only different crystal packing modes, but also the formation of internal Haggregation. These three phosphor powders exhibited dual emissions of blue fluorescence and yellow phosphorescence at room temperature, with luminescence lifetimes of 0.16−0.34 s. Theoretical calculations indicated that different numbers of effective intersystem crossing channels between CzDCIT, BiCzDT, or TCzT were responsible for the luminescence lifetimes. After doping the phosphors into the polymer matrix, they exhibited good persistent phosphorescence and high recoverability in multiple compression-grinding cycles. ASTAR (Agency for Sci., Tech. and Research, S’pore) Accepted version

Fully biodegradable and environmentally-friendly luminescent films were fabricated by doping the long-persistent luminescence inorganic phosphors containing europium ions into poly(3-hydrox...

Highlights Small size V2SnC MAX phase was prepared by the molten salt method. V2SnC MAX phase electrode is able to deliver high gravimetric capacity up to 490 mAh g−1 and volumetric capacity of 570 mAh cm−3 A charge storage mechanism with V2C-Li redox and Sn–Li alloying dual reactions was proposed Supplementary Information The online version contains supplementary material available at 10.1007/s40820-021-00684-6., MAX phases are gaining attention as precursors of two-dimensional MXenes that are intensively pursued in applications for electrochemical energy storage. Here, we report the preparation of V2SnC MAX phase by the molten salt method. V2SnC is investigated as a lithium storage anode, showing a high gravimetric capacity of 490 mAh g−1 and volumetric capacity of 570 mAh cm−3 as well as superior rate performance of 95 mAh g−1 (110 mAh cm−3) at 50 C, surpassing the ever-reported performance of MAX phase anodes. Supported by operando X-ray diffraction and density functional theory, a charge storage mechanism with dual redox reaction is proposed with a Sn–Li (de)alloying reaction that occurs at the edge sites of V2SnC particles where Sn atoms are exposed to the electrolyte followed by a redox reaction that occurs at V2C layers with Li. This study offers promise of using MAX phases with M-site and A-site elements that are redox active as high-rate lithium storage materials. Supplementary Information The online version contains supplementary material available at 10.1007/s40820-021-00684-6.