Publications by authors named "Dongpeng Yan"

81 Publications

A Lamellibranchia-inspired epidermal electrode for electrophysiology.

Mater Horiz 2021 Mar 27;8(3):1047-1057. Epub 2021 Jan 27.

Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China.

The capability to accurately monitor electrophysiological signals and instantly provide feedback to users is crucial for wearable healthcare. However, commercial gel electrodes suffer from drying out and irritation on skin with time, severely affecting signal quality for practical use. Toward a gel-free electrophysiology, epidermal electrodes that can accurately detect biosignals and simultaneously achieve the multifunctional properties of on-skin electronics needs are highly desirable. In this work, inspired by Lamellibranchia, which can adhere tightly to various surfaces using their extensible, adhesive and self-healing byssal threads, we developed a gel-free epidermal electrode to acquire high-quality electrophysiological signals based on a novel polymer substrate design. This polymer (STAR) features extreme stretchability (>2300% strain), high transparency (>90% transmittance at λ = 550 nm), gentle adhesion (adhesion strengths: tens of kPa), and rapid self-healing ability (95% healing efficiency in 10 min). Combined with silver nanowires as conductors, STAR was employed as a self-healing, stretchable and adhesive epidermal electrode for electrophysiological signal recording, showing a signal-to-noise ratio (SNR) even higher than that of commercial electrodes, and being able to control an artificial limb as an intermediate for human-machine interface. We believe our Lamellibranchia inspired STAR will pave a new way to design multifunctional polymers for epidermal electronics, accelerating the development of emerging wearable healthcare.
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http://dx.doi.org/10.1039/d0mh01656jDOI Listing
March 2021

Room-Temperature Phosphorescent Co-Crystal Showing Direct White Light and Photo-Electric Conversion.

Front Chem 2021 4;9:765374. Epub 2021 Nov 4.

College of Chemistry, Beijing Key Laboratory of Energy Conversion and Storage Materials, Beijing Normal University, Beijing, China.

The development of molecular crystalline materials with efficient room-temperature phosphorescence has been obtained much attention due to their fascinating photophysical properties and potential applications in the fields of data storage, bioimaging and photodynamic therapy. Herein, a new co-crystal complex [(DCPA) (AD)] (DCPA = 9,10-di (4-carboxyphenyl)anthracene; AD = acridine) has been synthesized by a facile solvothermal process. Crystal structure analysis reveals that the co-crystal possesses orderly and alternant arrangement of DCPA donors and AD acceptors at molecular level. Fixed by strong hydrogen bonds, the DCPA molecule displays seriously twisty spatial conformation. Density functional theory (DFT) calculations show well separation of HOMO and LUMO for this co-crystal system, suggesting the efficient triplet excitons generation. Photoluminescence measurements show intensive cyan fluorescence (58.20 ns) and direct white phosphorescence (325 µs) emission at room-temperature. The transient current density-time curve reveals a typical switching electric response under the irradiation of simulated light, reveal that the [(DCPA) (AD)] co-crystal has a high photoelectric response performance.
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http://dx.doi.org/10.3389/fchem.2021.765374DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8600111PMC
November 2021

Dynamic Manipulating Space-resolved Persistent Luminescence in Core-shell MOFs Heterostructures via Reversible Photochromism.

Angew Chem Int Ed Engl 2021 Nov 7. Epub 2021 Nov 7.

Beijing Normal University, College of Chemistry, Xinjiekouwai street, No. 19, Haidian District, 100875, BEIJING, CHINA.

In this work, photo-controllable persistent luminescence at the single crystal level can be achieved by the integration of long-lived room temperature phosphorescence (RTP) and photochromism within metal-organic frameworks (MOFs) for the first time. Moreover, the multiblock core-shell heterojunctions have been prepared utilizing the isostructural MOFs through an epitaxial growth process, in which the shell exhibits bright yellow afterglow emission that gradually disappears upon further irradiation, but the core does not show such property. Benefitting from combined persistent luminescence and photochromic behavior, a multiple encryption demo can be facilely designed based on the dynamic manipulating RTP via reversible photochromism. Therefore, this work not only develops new types of dynamically photo-controllable afterglow switch, but also provides a method to obtain MOFs-based optical heterojunctions towards potential space/time-resolved information encryption and anti-counterfeiting applications.
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http://dx.doi.org/10.1002/anie.202114100DOI Listing
November 2021

Mo S Intercalated Layered Double Hydroxide: Highly Selective Removal of Heavy Metals and Simultaneous Reduction of Ag Ions to Metallic Ag Ribbons.

Angew Chem Int Ed Engl 2021 Oct 28. Epub 2021 Oct 28.

Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA.

We demonstrate a new material by intercalating Mo S into Mg/Al layered double hydroxide (abbr. Mo S -LDH), exhibiting excellent capture capability for toxic Hg and noble metal silver (Ag). The as-prepared Mo S -LDH displays ultra-high selectivity of Ag , Hg and Cu in the presence of various competitive ions, with the order of Ag >Hg >Cu >Pb ≥Co , Ni , Zn , Cd . For Ag and Hg , extremely fast adsorption rates (≈90 % within 10 min, >99 % in 1 h) are observed. Much high selectivity is present for Ag and Cu , especially for trace amounts of Ag (≈1 ppm), achieving a large separation factor (SF ) of ≈8000 at the large Cu/Ag ratio of 520. The overwhelming adsorption capacities for Ag (q =1073 mg g ) and Hg (q =594 mg g ) place the Mo S -LDH at the top of performing sorbent materials. Most importantly, Mo S -LDH captures Ag via two paths: a) formation of Ag S due to Ag-S complexation and precipitation, and b) reduction of Ag to metallic silver (Ag ). The Mo S -LDH is a promising material to extract low-grade silver from copper-rich minerals and trap highly toxic Hg from polluted water.
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http://dx.doi.org/10.1002/anie.202112511DOI Listing
October 2021

Transition metal-based layered double hydroxides for photo(electro)chemical water splitting: a mini review.

Nanoscale 2021 Aug 4;13(32):13593-13603. Epub 2021 Aug 4.

Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, and Key Laboratory of Radiopharmaceuticals, Ministry of Education, Beijing Normal University, Beijing 100875, P. R. China.

The conversion of solar energy into usable chemical fuels, such as hydrogen gas, via photo(electro)chemical water splitting is a promising approach for creating a carbon neutral energy ecosystem. The deployment of this technology industrially and at scale requires photoelectrodes that are highly active, cost-effective, and stable. To create these new photoelectrodes, transition metal-based electrocatalysts have been proposed as potential cocatalysts for improving the performance of water splitting catalysts. Layered double hydroxides (LDHs) are a class of clays with brucite like layers and intercalated anions. Transition metal-based LDHs are increasingly popular in the field of photo(electro)chemical water splitting due to their unique physicochemical properties. This article aims to review recent advances in transition metal-based LDHs for photo(electro)chemical water splitting. This article provides a brief overview of the research in a format approachable for the general scientific audience. Specifically, this review examines the following areas: (i) routes for synthesis of transition metal-based LDHs, (ii) recent developments in transition metal-based LDHs for photo(electro)chemical water splitting, and (iii) an overview of the structure-property relationships therein.
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http://dx.doi.org/10.1039/d1nr03409jDOI Listing
August 2021

High-Efficiency Flame Retardants of a P-N-Rich Polyphosphazene Elastomer Nanocoating on Cotton Fabric.

ACS Appl Mater Interfaces 2021 Jul 5;13(27):32094-32105. Epub 2021 Jul 5.

State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China.

Modification by intumescent flame retardants is an effective way to impart antiflame properties to fabric materials. Polyphosphazene elastomers contain all three elements required by intumescent flame retardants: an acid source, a gas source, and a carbon source, making them all-in-one integrated intumescent flame retardants. In this work, halogen-free poly(dimethoxy)phosphazene (PDMP) loaded with 29.0 wt % phosphorus and 13.1 wt % nitrogen is shown to be an ideal flame retardant for fabric materials. For the first time, transparent and elastic PDMP was applied as an intumescent flame retardant for cotton fabric. The PDMP-coated cotton shows remarkable high-efficiency flame-retardant properties: (1) a self-extinguishing property during the vertical flame test is obtained when the add-on level reaches 5.3 wt %, with a lower smoke release character; (2) the limiting oxygen index (LOI) values of coated cotton are improved with increasing add-on level, and the thickness of the coating is measured to be at the nanolevel, 2540 nm when 10.9 wt % PDMP is coated. The coated cotton shows enhanced carbonization ability at lower temperatures, which is the key to imparting flame-retardant properties to cotton, and the PDMP-coated cotton shows remarkably lower peak heat release rate and total heat release compared to the control cotton during combustion. The durability of modified cotton was tested after 50 laundering cycles, which showed that the coating maintains 80% of its initial mass, and the after-laundering sample preserves the characteristics of self-extinguishing and a high LOI. Thus, the PDMP nanocoating-modified flame-retardant cotton fabric is sufficiently durable for practical application.
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http://dx.doi.org/10.1021/acsami.1c05884DOI Listing
July 2021

A pH-responsive ultrathin Cu-based nanoplatform for specific photothermal and chemodynamic synergistic therapy.

Chem Sci 2021 Jan 11;12(7):2594-2603. Epub 2021 Jan 11.

State Key Laboratory of Chemical Resource Engineering, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology Beijing 100029 P. R. China

Noninvasive tumor therapy requires a new generation of bionanomaterials towards sensitive response to the unique tumor microenvironment to achieve accurate and effective treatment. Herein, we have developed a tumor therapy nanoplatform by immobilizing natural glucose oxidase (GOD) onto Cu-based layered double hydroxide (CuFe-LDH) nanosheets, which for the first time integrates acid-enhanced photothermal therapy (PTT), and pH-responsive and heat-facilitated chemodynamic therapy (CDT) simultaneously. As demonstrated by EXAFS and HRTEM, CuFe-LDH nanosheets possess a considerable number of defects caused by different acid conditions, resulting in a significantly acid-enhanced photothermal conversion efficiency (83.2% at pH 5.4 46.0% at pH 7.4). Moreover, GOD/CuFe-LDH nanosheets can convert a cascade of glucose into hydroxyl radicals (˙OH) under tumor acid conditions, which is validated by a high maximum velocity ( = 2.00 × 10 M) and low Michaelis-Menten constant ( = 12.01 mM). With the combination of PTT and CDT, the tumor tissue is almost eliminated with low-dose drug injection (1 mg kg). Therefore, this novel pH-responsive Cu-based nanoplatform holds great promise in tumor-specific CDT/PTT synergistic therapy.
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http://dx.doi.org/10.1039/d0sc06742cDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8179329PMC
January 2021

Triple-mode tunable long-persistent luminescence in a 3D zinc-organic hybrid.

Chem Commun (Camb) 2021 Jul;57(54):6684-6687

Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China. and Key Laboratory of Radiopharmaceuticals, Ministry of Education, Beijing Normal University, Beijing 100875, People's Republic of China and College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou, 450001, China.

A 3D zinc-organic hybrid [Zn3(D-Cam)3(tib)2]·2H2O (1) exhibits triple-mode dependent (including excitation wavelength, time and temperature) long-persistent luminescence. Experimental and theoretical calculations support that the long lifetime and color-tunable afterglow may be due to the dispersive electronic state distribution. Furthermore, the hybrid is also used for optical anti-counterfeiting and information encryption applications.
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http://dx.doi.org/10.1039/d1cc02389fDOI Listing
July 2021

Low-Dimensional Organic Metal Halide Hybrids with Excitation-Dependent Optical Waveguides from Visible to Near-Infrared Emission.

ACS Appl Mater Interfaces 2021 Jun 27;13(22):26451-26460. Epub 2021 May 27.

Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China.

Molecular luminescent materials with optical waveguide properties have wide application prospects in the fields of sensors, filters, and modulators. However, designing and synthesizing optical waveguide materials with unique morphology, high emissive efficiency, and tunable optical properties in the same solid-state system remains an open challenge. In this work, we report new types of morphological one-dimensional (1D) organic metal halide hybrid micro/nanotubes and micro/nanorods, which exhibit excitation-dependent optical waveguide properties from visible to near-infrared (NIR) regions with low-loss coefficient and high emissive efficiency during the propagation process. Strong intermolecular interactions within the hybrid systems could effectively reduce the nonradiative transition and improve quantum efficiency. Photophysical studies and theoretical calculations demonstrate that the color-tunable emission can be attributed to the coexistence of locally excited states and charge-transfer states. Utilizing excitation-dependent optical waveguide emission ranging from visible to NIR regions, we fabricate an optical wavelength converter to transfer short-wavelength into long-wavelength emission with multichannels. Furthermore, an optical logic gate system was designed based on the tunable emission properties of the 1D metal halide micro/nanotubes. Therefore, this work provides not only a facile process to synthesize 1D organic metal halide hybrids with excitation-dependent optical waveguide properties but also a new way to advance photofunctional logic computation at the micro/nanoscale.
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http://dx.doi.org/10.1021/acsami.1c03926DOI Listing
June 2021

Room-Temperature Phosphorescent Organic-Doped Inorganic Frameworks Showing Wide-Range and Multicolor Long-Persistent Luminescence.

Research (Wash D C) 2021 9;2021:9862327. Epub 2021 Apr 9.

Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry Beijing Normal University, Beijing 100875, China.

Long-persistent luminescence based on purely inorganic and/or organic compounds has recently attracted much attention in a wide variety of fields including illumination, biological imaging, and information safety. However, simultaneously tuning the static and dynamic afterglow performance still presents a challenge. In this work, we put forward a new route of organic-doped inorganic framework to achieve wide-range and multicolor ultralong room-temperature phosphorescence (RTP). Through a facile hydrothermal method, phosphor (tetrafluoroterephthalic acid (TFTPA)) into the CdCO (or Zn(OH)CO) host matrix exhibits an excitation-dependent colorful RTP due to the formation of diverse molecular aggregations with multicentral luminescence. The RTP lifetime of the doped organic/inorganic hybrids is greatly enhanced (313 times) compared to the pristine TFTPA. The high RTP quantum yield (43.9%) and good stability guarantee their easy visualization in both ambient and extreme conditions (such as acidic/basic solutions and an oxygen environment). Further codoped inorganic ions (Mn and Pb) afford the hybrid materials with a novel time-resolved tunable afterglow emission, and the excitation-dependent RTP color is highly adjustable from dark blue to red, covering nearly the whole visible spectrum and outperforming the current state-of-the-art RTP materials. Therefore, this work not only describes a combined codoping and multicentral strategy to obtain statically and dynamically tunable long-persistent luminescence but also provides great opportunity for the use of organic-inorganic hybrid materials in multilevel anticounterfeiting and multicolor display applications.
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http://dx.doi.org/10.34133/2021/9862327DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8053305PMC
April 2021

Ag/Ultrathin-Layered Double Hydroxide Nanosheets Induced by a Self-Redox Strategy for Highly Selective CO Reduction.

ACS Appl Mater Interfaces 2021 Apr 1;13(14):16536-16544. Epub 2021 Apr 1.

State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China.

The carbon-neutral photocatalytic CO reduction reaction (CORR) enables the conversion of CO into hydrocarbon fuels or value-added chemicals under mild conditions. Achieving high selectivity for the desired products of the CORR remains challenging. Herein, a self-redox strategy is developed to construct strong interfacial bonds between Ag nanoparticles and an ultrathin CoAl-layered double hydroxide (U-LDH) nanosheet support, where the surface hydroxyl groups associated with oxygen vacancies of U-LDH play a critical role in the formation of the interface structure. The supported [email protected] acts as a highly efficient catalyst for CO reduction, resulting in a high CO evolution rate of 757 μmol g h and a CO selectivity of 94.5% under light irradiation. Such a high catalytic selectivity may represent a new record among current photocatalytic CORR to CO systems. The Ag-O-Co interface bonding is confirmed by Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and FTIR CO adsorption studies. The in situ FTIR measurements indicate that the formation of the *COOH intermediate is accelerated and the mass transfer is improved during the CORR. Density functional theory calculations show that the Ag-O-Co interface reduces the formation energy of the *COOH intermediate and accumulates localized charge. Experimental and theoretical analysis collectively demonstrates that the strong interface bonding between Ag and U-LDH activates the interface structure as catalytically CORR active sites, effectively optimizing the binding energies with reacted intermediates and facilitating the CORR performance.
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http://dx.doi.org/10.1021/acsami.1c02737DOI Listing
April 2021

Recent advances in persistent luminescence based on molecular hybrid materials.

Chem Soc Rev 2021 May 10;50(9):5564-5589. Epub 2021 Mar 10.

Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, and Key Laboratory of Radiopharmaceuticals, Ministry of Education, Beijing Normal University, Beijing 100875, People's Republic of China.

Molecular persistently luminescent materials have received recent attention due to their promising applications in optical displays, biological imaging, chemical sensing, and security systems. In this review, we systematically summarize recent advances in establishing persistently luminescent materials-specifically focusing on materials composed of molecular hybrids for the first time. We describe the main strategies for synthesizing these hybrid materials, namely: (i) inorganics/organics, (ii) organics/organics, and (iii) organics/polymer systems and demonstrate how molecular hybrids provide synergistic effects, while improving luminescence lifetimes and efficiencies. These hybrid materials promote new methods for tuning key physical properties such as singlet-triplet excited state energies by controlling the chemical interactions and molecular orientations in the solid state. We review new advances in these materials from the perspective of examining experimental and theoretical approaches to room-temperature phosphorescence and thermally-activated delayed fluorescence. Finally, this review concludes by summarizing the current challenges and future opportunities for these hybrid materials.
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http://dx.doi.org/10.1039/d0cs01463jDOI Listing
May 2021

Boosting Wide-Range Tunable Long-Afterglow in 1D Metal-Organic Halide Micro/Nanocrystals for Space/Time-Resolved Information Photonics.

Adv Mater 2021 Apr 9;33(16):e2007571. Epub 2021 Mar 9.

Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University, Beijing, 100875, P. R. China.

Molecular afterglow materials with ultralong-lived excited states have attracted considerable interest owing to their promise for light-emitting devices, optical imaging, and anti-counterfeiting applications. However, the realization of ultralong afterglow emission in low-dimensional micro/nanostructures has remained an open challenge, limiting progress toward new-generation photonic applications. In this work, new types of mono/binuclear metal-organic halide micro/nanocrystals with tunable afterglow properties, made possibly by the rational control over both ultralong-lived room-temperature phosphorescence and thermally activated delayed fluorescence, are developed. Interestingly, the mono/binuclear coordination complexes present excitation-dependent luminescence across a wide range (wavelength > 150 nm) with broad emission color differences from blue to yellow owing to the multiple long-lived excited states. The 1D binuclear metal-organic microrods further exhibit excitation-dependent optical waveguide and space/time dual-resolved afterglow emission properties, endowing them with great potential in wavelength-division multiplexing information photonics and logic gates. Therefore, this work not only communicates the first example of wide-range tunable ultralong afterglow of low-dimensional metal-organic micro/nanocrystals under ambient conditions but also provides a new route to achieve optical communications and photonic logic compilation at the micro/nanoscale.
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http://dx.doi.org/10.1002/adma.202007571DOI Listing
April 2021

Research Progress in Organic Synthesis by Means of Photoelectrocatalysis.

Chem Rec 2021 Apr 3;21(4):841-857. Epub 2021 Mar 3.

Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, and Key Laboratory of Radiopharmaceuticals, Ministry of Education, Beijing Normal University, Beijing, 100875, P. R. China.

The rapid development of radical chemistry has spurred several innovative strategies for organic synthesis. The novel approaches for organic synthesis play a critical role in promoting and regulating the single-electron redox activity. Among them, photoelectrocatalysis (PEC) has attained considerable attention as the most promising strategy to convert organic compounds into fine chemicals. This review highlights the current progress in organic synthesis through PEC, including various catalytic reactions, catalyst systems and practical applications. The numerous catalytic reactions suffer the high overpotential and poor conversion efficiency, depending on the design of electrolyzers and the reaction mechanisms. We also considered the recent developments with special emphasis on scientific problems and efficient solutions, which enhance accessibility to utilize and further develop the photoelectrocatalytic technology for the specific chemical bonds formation and the fabrication of numerous catalytic systems.
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http://dx.doi.org/10.1002/tcr.202000186DOI Listing
April 2021

Wide range zero-thermal-quenching ultralong phosphorescence from zero-dimensional metal halide hybrids.

Nat Commun 2020 Sep 16;11(1):4649. Epub 2020 Sep 16.

Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University, 100875, Beijing, P. R. China.

Materials with ultralong phosphorescence have wide-ranging application prospects in biological imaging, light-emitting devices, and anti-counterfeiting. Usually, molecular phosphorescence is significantly quenched with increasing temperature, rendering it difficult to achieve high-efficiency and ultralong room temperature phosphorescence. Herein, we spearhead this challenging effort to design thermal-quenching resistant phosphorescent materials based on an effective intermediate energy buffer and energy transfer route. Co-crystallized assembly of zero-dimensional metal halide organic-inorganic hybrids enables ultralong room temperature phosphorescence of (PhP)CdBr that maintains luminescent stability across a wide temperature range from 100 to 320 K (ΔT = 220 °C) with the room temperature phosphorescence quantum yield of 62.79% and lifetime of 37.85 ms, which exceeds those of other state-of-the-art systems. Therefore, this work not only describes a design for thermal-quenching-resistant luminescent materials with high efficiency, but also demonstrates an effective way to obtain intelligent systems with long-lasting room temperature phosphorescence for optical storage and logic compilation applications.
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http://dx.doi.org/10.1038/s41467-020-18482-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7494901PMC
September 2020

Manipulating Light-Induced Dynamic Macro-Movement and Static Photonic Properties within 1D Isostructural Hydrogen-Bonded Molecular Cocrystals.

Angew Chem Int Ed Engl 2020 Dec 6;59(50):22623-22630. Epub 2020 Oct 6.

Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University, Beijing, 100875, P. R. China.

Smart molecular crystals with light-driven mechanical responses have received interest owing to their potential uses in molecular machines, artificial muscles, and biomimetics. However, challenges remain in control over both the dynamic photo-mechanical behaviors and static photonic properties of molecular crystals based on the same molecule. Herein, we show the construction of isostructural co-crystals allows their light-induced cracking and jumping behaviors (photosalient effect) to be controlled. Hydrogen-bonded co-crystals from 4-(1-naphthylvinyl)pyridine (NVP) with co-formers (tetrafluoro-4-hydroxybenzoic acid (THA) and tetrafluorobenzoic acid (TA)) crystallize as isostructural crystals, but have different static and dynamic photo-mechanical behaviors. These differences are due to alternations in the orientation of NVP and hydrogen-bonding modes of the co-formers. After light activation, the 1D NVP-TA crystal splits and shears off within 1 s. For NVP-THA, its photostability and high quantum yield give novel photonic properties, including low optical waveguide loss, highly polarized anisotropy, and efficient up-conversion fluorescence.
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http://dx.doi.org/10.1002/anie.202009714DOI Listing
December 2020

Fast Crystallization-Deposition of Orderly Molecule Level Heterojunction Thin Films Showing Tunable Up-Conversion and Ultrahigh Photoelectric Response.

ACS Cent Sci 2020 Jul 24;6(7):1169-1178. Epub 2020 Jun 24.

College of Chemistry, Beijing Normal University, Beijing Key Laboratory of Energy Conversion and Storage Materials, Beijing 100875, P. R. China.

Molecular cocrystals have received much attention for tuning physicochemical properties in pharmaceutics, luminescence, organic electronics, and so on. However, the effective methods for the formation of orderly cocrystal thin films are still rather limited, which have largely restricted their photofunctional and optoelectronic applications. In this work, a fast crystallization-deposition procedure is put forward to obtain acridine (AD)-based cocrystals, which are self-assembled with three typical isophthalic acid derivatives (IPA, IPB, and TMA). The obtained donor-acceptor cocrystal complexes exhibit an adjustable energy level, wide range of photoluminescence color, and rotational angle-dependent polarized emission. The orderly and uniform cocrystal thin films further present tunable one-/two-photon up-conversion and different semiconductor properties. Particularly, AD-TMA cocrystal thin film shows a rare example of a molecule level heterojunction with the alternating arrangement of AD electronic acceptor layers and TMA electronic donor layers, and thus, provides a way for efficient mobility and separation of electron-hole pairs. A large on-off photocurrent ratio of more than 10 can be achieved for the AD-TMA thin film, which is higher than state-of-the-art molecular semiconductor systems. Therefore, this work extends the application scopes of orderly cocrystal thin film materials for future luminescent and optoelectronic micro-/nanodevices.
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http://dx.doi.org/10.1021/acscentsci.0c00447DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7379383PMC
July 2020

Mechanistic In Situ and Ex Situ Studies of Phase Transformations in Molecular Co-Crystals.

Chemistry 2020 Nov 7;26(64):14645-14653. Epub 2020 Oct 7.

UCL School of Pharmacy, University College London, 29-39 Brunswick Square, London, WC1N 1AX, UK.

Co-crystallisation is widely explored as a route to improve the physical properties of pharmaceutical active ingredients, but little is known about the fundamental mechanisms of the process. Herein, we apply a hyphenated differential scanning calorimetry-X-ray diffraction technique to mimic the commercial hot melt extrusion process, and explore the heat-induced synthesis of a series of new co-crystals containing isonicotinamide. These comprise a 1:1 co-crystal with 4-hydroxybenzoic acid, 2:1 and 1:2 systems with 4-hydroxyphenylacetic acid and a 1:1 crystal with 3,4-dihydroxyphenylactic acid. The formation of co-crystals during heating is complex mechanistically. In addition to co-crystallisation, conversions between polymorphs of the co-former starting materials and co-crystal products are also observed. A subsequent study exploring the use of inkjet printing and milling to generate co-crystals revealed that the synthetic approach has a major effect on the co-crystal species and polymorphs produced.
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http://dx.doi.org/10.1002/chem.202002267DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7756291PMC
November 2020

Tunable room temperature phosphorescence and energy transfer in ratiometric co-crystals.

Chem Commun (Camb) 2020 Jul;56(56):7698-7701

Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China. and College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001, P. R. China.

Two co-crystals (BTA-ME-1 and BTA-ME-2) assembled with the same building blocks but in different ratios exhibit alternative stacking modes, relative orientations and aggregation states, leading to color-tunable green and yellow room temperature phosphorescence (RTP) and different intermolecular energy transfer efficiencies, respectively. Based on the time-resolved afterglow properties of the RTP emission, BTA-ME-2 is further applied for signal-visualized information encryption.
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http://dx.doi.org/10.1039/d0cc02730hDOI Listing
July 2020

Luminescent Polymorphic Co-crystals: A Promising Way to the Diversity of Molecular Assembly, Fluorescence Polarization, and Optical Waveguide.

ACS Appl Mater Interfaces 2020 Jul 30;12(28):31940-31951. Epub 2020 Jun 30.

Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University, Beijing 100875, People's Republic of China.

The design of molecular optoelectronic materials based on fabricating polymorphs and/or co-crystals has received much recent attention in the fields of luminescence, sensors, nonlinear optics, and so on. If the advantages of the two crystal engineering strategies above were combined, the diversity of self-assembly fashions and the tuning of photofunctional performances would be largely extended. However, such multicomponent examples have still been very limited to date. Herein, we report the construction of luminescent polymorphic co-crystals by assembly of tris(pentafluorophenyl)borane (TPFB) with 9,10-dicyanoanthracene (DCA) and acridine (AC) as paradigms. Different stacking modes and arrangement styles based on identical building block units in polymorphic co-crystals result in adjustable crystalline morphologies and variant photophysical properties (such as fluorescence wavelength, lifetimes, and up-conversion luminescence). The optimized photoluminescence quantum yield (63.1%) and lifetime (57.1 ns) are much higher than those of the pristine assembled units. In addition, two polymorphic co-crystals ([email protected] and [email protected]) present prominent fluorescence polarization and optical waveguide behaviors due to the highly regulated molecular orientation. Their high one-dimensional luminescence anisotropy (0.652) and low optical waveguide loss (0.0079 dB/μm) outperform most state-of-the-art low-dimensional molecular systems and thus endow them with great opportunities for photonic materials and devices. Therefore, this work not only confirms that constructing polymorphic co-crystals can be an effective way to design new photofunctional materials for luminescence and photonic applications but also discloses a deep understanding on the relationship between variant self-assembled fashions and tunable photofunctional properties of new TPFB-based molecular materials.
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http://dx.doi.org/10.1021/acsami.0c06794DOI Listing
July 2020

One-dimensional co-crystallized coordination polymers showing reversible mechanochromic luminescence: cation-anion interaction directed rapid self-recovery.

Chem Commun (Camb) 2020 May 9;56(39):5267-5270. Epub 2020 Apr 9.

Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China.

Three one-dimensional (1D) chain polymers (1D-9HAC, 1D-Cd-9AC, and 1D-Cd-9AC-HBIM) that exhibit different intermolecular interactions and stacking patterns have been designed and synthesized. Only 1D-Cd-9AC-HBIM with rigid (anion) and flexible (cation) units alternately arranged exhibits mechanochromic luminescence, which can be recovered through rapid solvent treatment or a self-recovery process.
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http://dx.doi.org/10.1039/c9cc09806bDOI Listing
May 2020

Highly Efficient Organic Afterglow from a 2D Layered Lead-Free Metal Halide in Both Crystals and Thin Films under an Air Atmosphere.

ACS Appl Mater Interfaces 2020 Jan 27;12(1):1419-1426. Epub 2019 Dec 27.

Fujian Key Laboratory of Polymer Materials, College of Chemistry and Materials Science , Fujian Normal University , Fuzhou 350007 , China.

Organic afterglow materials (OAMs) with a lifetime longer than 0.1 s have recently received much attention for their fascinating properties meeting the critical requirements of applications in newly emerged technologies. However, the development of OAMs lags behind for their low luminescence efficiency. Usually, enhancing the phosphorescence efficiency of organic materials causes a short lifetime. Here, we report two kinds of OAMs, two-dimensional (2D) layered organic-inorganic hybrid zinc bromides (PEZB-NTA and PEZB-BPA), obtained in an environmentally friendly ethanol solvent by a low-temperature solution method. They display highly efficient and persistent luminescence in air in both crystals and thin films with phosphorescence quantum yields up to 42% in crystals and 27% in films. For OAMs, the two quantum yields are the highest values ever reported for crystals and films. Due to the excellent crystalline and film-forming ability, PEZB-NTA and PEZB-BPA in ethanol can be used as inks to construct patterns on various rigid and flexible substrates, including paper, iron, plastic, marble, tin foil, and cloth. Consequently, the novel OAMs show great application prospects in the fields of anti-counterfeiting and information storage because of their economic synthesis, solution processing, and easy operation.
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http://dx.doi.org/10.1021/acsami.9b20502DOI Listing
January 2020

Zinc anode-compatible in-situ solid electrolyte interphase via cation solvation modulation.

Nat Commun 2019 11 26;10(1):5374. Epub 2019 Nov 26.

Qingdao Industrial Energy Storage Research Institute, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, P. R. China.

The surface chemistry of solid electrolyte interphase is one of the critical factors that govern the cycling life of rechargeable batteries. However, this chemistry is less explored for zinc anodes, owing to their relatively high redox potential and limited choices in electrolyte. Here, we report the observation of a zinc fluoride-rich organic/inorganic hybrid solid electrolyte interphase on zinc anode, based on an acetamide-Zn(TFSI) eutectic electrolyte. A combination of experimental and modeling investigations reveals that the presence of anion-complexing zinc species with markedly lowered decomposition energies contributes to the in situ formation of an interphase. The as-protected anode enables reversible (~100% Coulombic efficiency) and dendrite-free zinc plating/stripping even at high areal capacities (>2.5 mAh cm), endowed by the fast ion migration coupled with high mechanical strength of the protective interphase. With this interphasial design the assembled zinc batteries exhibit excellent cycling stability with negligible capacity loss at both low and high rates.
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http://dx.doi.org/10.1038/s41467-019-13436-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6879498PMC
November 2019

Simultaneous Long-Persistent Blue Luminescence and High Quantum Yield within 2D Organic-Metal Halide Perovskite Micro/Nanosheets.

Angew Chem Int Ed Engl 2019 Oct 13;58(42):15128-15135. Epub 2019 Sep 13.

College of Chemistry, Beijing Normal University, Beijing Key Laboratory of Energy Conversion and Storage Materials, Beijing, 100875, P. R. China.

Molecular solid-state materials with long-lived luminescence (such as thermally activated delayed fluorescence (TADF) and room temperature phosphorescence (RTP) systems) are promising for display, sensoring, and bio-imaging applications. However, the design of such materials that exhibit both long luminescent lifetime and high solid-state emissive efficiency remains an open challenge. Two-dimensional (2D) organic-metal halide perovskite materials have a high blue-emitting quantum yield of up to 63.55 % and ultralong TADF lifetime of 103.12 ms at ambient temperature and atmosphere. Our design leverages the combined influences of a 2D space/electronic confinement effect and a modest heavy-atom tuning strategy. Photophysical studies and calculations reveal that the enhanced quantum yield is due to the rigid laminate structure of perovskites, which can effectively inhibit the non-radiative decay of excitons.
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http://dx.doi.org/10.1002/anie.201909760DOI Listing
October 2019

Efficient Photoelectrochemical Route for the Ambient Reduction of N to NH Based on Nanojunctions Assembled from MoS Nanosheets and TiO.

ACS Appl Mater Interfaces 2019 Aug 1;11(32):28809-28817. Epub 2019 Aug 1.

Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry , Beijing Normal University , Beijing 100875 , P. R. China.

Efficient nitrogen fixation under ambient conditions is an exigent task in both basic research and industrial applications. Recently, reduction of N to NH based on photocatalysis and/or electrocatalysis offers a possible route to the typical Haber-Bosch process. However, achieving a high yield of N reduction reaction (NRR) is still a challenging goal because of the limitations of efficient catalysts. Herein, we propose a photoelectrochemical NRR route based on the rational design of [email protected] semiconductor nanojunction catalysts through a facile hydrothermal synthetic method. The developed [email protected] photocathode attains a high NH yield rate (1.42 × 10 mol h cm) and a superhigh faradaic efficiency (65.52%), which is the highest record to the best of our knowledge. Moreover, [email protected] exhibits high stability over 10 consecutive reaction cycles. Therefore, this work demonstrates an effective NRR photoelectrocatalyst and results in a breakthrough in the low faradaic efficiency because of the interfacial electronic coupling and synergistic effects between the MoS and TiO components.
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http://dx.doi.org/10.1021/acsami.9b06596DOI Listing
August 2019

C-Adsorbed Single-Walled Carbon Nanotubes as Metal-Free, pH-Universal, and Multifunctional Catalysts for Oxygen Reduction, Oxygen Evolution, and Hydrogen Evolution.

J Am Chem Soc 2019 Jul 9;141(29):11658-11666. Epub 2019 Jul 9.

Center of Advanced Science and Engineering for Carbon (Case4Carbon), Department of Macromolecular Sciences and Engineering , Case Western Reserve University , Cleveland , Ohio 44106 , United States.

Buckminsterfullerene (C) was adsorbed onto single-walled carbon nanotubes (SWCNTs) as an electron-acceptor to induce intermolecular charge-transfer with the SWCNTs, leading to a class of new metal-free C-SWCNT electrocatalysts. For the first time, these newly developed C-SWCNTs were demonstrated to act as trifunctional metal-free catalysts for oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) over a wide range of pH values, from acid to alkaline, with even higher electrocatalytic activities and better long-term stabilities than those of commercial Pt and RuO counterparts. Thus, the adsorption-induced intermolecular charge-transfer with the C electron-acceptor can provide a general approach to high-performance, metal-free, pH-universal carbon-based trifunctional metal-free electrocatalysts for water-splitting and beyond.
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http://dx.doi.org/10.1021/jacs.9b05006DOI Listing
July 2019

A Cocrystal Precursor Strategy for Carbon-Rich Graphitic Carbon Nitride toward High-Efficiency Photocatalytic Overall Water Splitting.

iScience 2019 Jun 15;16:22-30. Epub 2019 May 15.

Beijing Key Laboratory of Energy Conversion and Storage Materials College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China; State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, P. R. China. Electronic address:

Direct and efficient photocatalytic overall water splitting is crucial for the sustainable conversion and storage of renewable solar energy. Herein, we present the design of a carbon-rich graphitic carbon nitride (C-CN), prepared from a layered molecular cocrystal precursor. The cocrystal microsheets were synthesized using a facile hydrothermal process. Following two-step thermal treatment and liquid exfoliation, the product maintains the 2D morphology owing to the toptactic transformation process. The C-CN exhibits an enhanced photogenerated electron-hole separation, high charge transport capacity, and prolonged lifetime of the carriers, relative to the g-CN system. In the absence of any sacrificial reagent or co-catalyst, the C-CN microsheets exhibit a high photocatalytic activity. The work presented in this report supplies a cocrystal route for the orderly molecular self-assembly of precursor materials to tailor the chemical compositions and electronic structures. Moreover, the generation of a highly efficient water-splitting photocatalyst has larger implications for sustainable energy applications.
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http://dx.doi.org/10.1016/j.isci.2019.05.015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6542374PMC
June 2019

Facile synthesis of 1D organic-inorganic perovskite micro-belts with high water stability for sensing and photonic applications.

Chem Sci 2019 May 8;10(17):4567-4572. Epub 2019 Mar 8.

Beijing Key Laboratory of Energy Conversion and Storage Materials , College of Chemistry , Beijing Normal University , Beijing 100875 , P. R. China . Email:

The development of low-dimensional perovskite micro/nanostructures with high water stability for novel photonic/electronic applications is highly desirable. Herein, one-dimensional (1D) organic-inorganic hybrid perovskite micro-belts [(AD)PbCl] (OIHP-AD, AD = acridine) were facilely synthesized through fast precipitation in aqueous solution at room temperature without any organic solvent and expensive alkyl halide. Luminescent properties and water stability are efficiently enhanced due to the highly regular arrangement of the protonated AD dyes with larger steric hindrance distributed in the perovskite host-guest system, which can afford denser crystal packing to prevent water erosion. The OIHP-AD micro-belts present upconversion fluorescence, polarized photoemission and optical waveguide performances with a low loss coefficient (0.004 dB μm) during propagation, thus extending the applications of 1D perovskite micro/nanostructures to potential optical communication micro-devices.
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http://dx.doi.org/10.1039/c9sc00162jDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6492630PMC
May 2019

Reversible Mechanochromic Delayed Fluorescence in 2D Metal-Organic Micro/Nanosheets: Switching Singlet-Triplet States through Transformation between Exciplex and Excimer.

Adv Sci (Weinh) 2018 Nov 27;5(11):1801187. Epub 2018 Sep 27.

Beijing Key Laboratory of Energy Conversion and Storage Materials College of Chemistry Beijing Normal University Beijing 100875 P. R. China.

Mechanochromic luminescent materials have attracted much attention and present a variety of applications in information security, data recording, and storage devices. However, most of these smart luminescent systems are based on typical fluorescence and/or phosphorescence mechanisms; the mechanochromic delayed fluorescence (MCDF) materials involving switching singlet and triplet states are rarely studied to date. Herein, new 2D layered metal-organic micro/nanosheets, [Cd(9-AC)(BIM)] (named as MCDF-1; 9-AC = anthracene-9-carboxylate and BIM = benzimidazole) and its solvate form containing interlayer CHCN (named as MCDF-2), which exhibit reversible mechanochromic delayed fluorescence characteristics, are presented. With applying the mechanical force, the luminescent center of MCDF-1 can be converted from 9-AC/BIM exciplex to 9-AC/9-AC excimer, resulting in alternations of delayed fluorescence. Such luminescent change can be further recovered by CHCN fumigation, accompanied by the structural transformation from MCDF-1 to MCDF-2. Furthermore, the force-responsive process also refers to the energy redistribution between singlet and triplet states as inferred by both temperature-dependent photophysics and theoretical calculations. Therefore, this work not only develops new 2D micro/nanosheets as MCDF materials, but also supplies a singlet-triplet energy switching mechanism on their reversible mechanochromic process.
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http://dx.doi.org/10.1002/advs.201801187DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6247076PMC
November 2018

A three-dimensional nickel-chromium layered double hydroxide micro/nanosheet array as an efficient and stable bifunctional electrocatalyst for overall water splitting.

Nanoscale 2018 Nov 15;10(41):19484-19491. Epub 2018 Oct 15.

Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University, Beijing 100875, People's Republic of China.

The development of bifunctional and stable non-noble metal electrocatalysts for the high-performance hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is very important and challenging for renewable energy. Herein, for the first time, a nickel-chromium layered double hydroxide (NiCr-LDH) nanosheet array was developed as a bifunctional electrocatalyst towards overall water splitting. By tuning different Ni/Cr ratios of LDHs, the optimized NiCr-LDH shows extraordinary HER activity with an ultralow overpotential of 138 mV at 100 mA cm, compared with all of the reported Ni-based LDHs (NiFe-LDH, NiCo-LDH, NiMn-LDH, NiTi-LDH, NiV-LDH etc.) and even outperforming Pt/C catalysts. The small overpotential of 319 mV at 100 mA cm for the OER and outstanding durability at 1.55 V (vs. RHE) for 30 hours can also be achieved for NiCr-LDH. Notably, a two-electrode electrolyzer with a NiCr-LDH bifunctional electrocatalyst as both the anode and the cathode can work for at least 30 hours with a cell voltage of merely 1.55 V at 10 mA cm. Both experimental and density functional theoretical calculations show that the Cr ions within the LDH layer serve as charge transfer sites and thus effectively boost the intrinsic electrochemical activity. Therefore, this work provides a new NiCr-LDH system as a more efficient metal hydroxide for bifunctional water splitting electrocatalyst.
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http://dx.doi.org/10.1039/c8nr05974hDOI Listing
November 2018
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