Publications by authors named "Qichun Zhang"

256 Publications

Employing Equivalent Circuit Models to Study the Performance of Selenium-Based Solar Cells with Polymers as Hole Transport Layers.

Small 2021 Sep 29;17(36):e2101226. Epub 2021 Jul 29.

School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore.

Selenium(Se)-based solar cells (SSCs), known as one of the oldest solar cells, have regained intense attention due to the advantages of Se including direct bandgap, good stability, and single absorber. Among all kinds of device structures, conventional n-i-p SSCs with top organic hole transport layers (HTLs) show great potential since organic HTLs could be well-designed to smoothly extract holes from the Se single absorber and protect the Se surface. However, till now, the performance of Se solar cells with organic HTLs is not as good as expected. To address this issue, herein, the SSCs are first presented with organic polymers as the HTLs with the improved efficiency up to 4.3%, which is the highest one in organic HTLs-based SSCs. Additionally, comparing with perovskite solar cells, it is found that the recombination process is the key factor that influences the performance of SSCs. It is believed that the further optimization of the Se active layer and the design of new and suitable organic HTLs for SSCs should be the main focus to suppress the undesired recombination processes of Se films. Such realization would boost the efficiency of the as-fabricated SSCs.
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http://dx.doi.org/10.1002/smll.202101226DOI Listing
September 2021

Recent progress on pristine two-dimensional metal-organic frameworks as active components in supercapacitors.

Dalton Trans 2021 Sep 27;50(33):11331-11346. Epub 2021 Jul 27.

Department of Chemistry, College of Sciences, Nanjing Agricultural University, Nanjing 210095, Jiangsu, P. R. China.

Two-dimensional (2D) metal-organic frameworks (MOFs) are a new generation of 2D materials that can provide uniform active sites and unique open channels as well as excellent catalytic abilities, interesting magnetic properties, and reasonable electrical conductivities. Thus, these MOFs are uniquely qualified for use in applications in energy-related fields or portable devices because they possess fast charge and discharge ability, high power density, and ultralong cycle life factors. There has been worldwide research interest in 2D conducting MOFs, and numerous techniques and strategies have been developed to synthesize these MOFs and their derivatives. Thus, this is the opportune time to review recent research progress on the development of 2D MOFs as electrodes in supercapacitors. This review covers synthetic design strategies, electrochemical performances, and working mechanisms. We will divide these 2D MOFs into two types on the basis of their conductive aspects: 2D conductive MOFs and 2D layered MOFs (including pillar-layered MOFs and 2D nanosheets). The challenges and perspectives of 2D MOFs are also provided.
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http://dx.doi.org/10.1039/d1dt01729bDOI Listing
September 2021

Recent Advance in Ionic-Liquid-Based Electrolytes for Rechargeable Metal-Ion Batteries.

Adv Sci (Weinh) 2021 Jul 2;8(13):2004490. Epub 2021 May 2.

Department of Materials Science and Engineering City University of Hong Kong Hong Kong 999077 China.

From basic research to industry process, battery energy storage systems have played a great role in the informatization, mobility, and intellectualization of modern human society. Some potential systems such as Li, Na, K, Mg, Zn, and Al secondary batteries have attracted much attention to maintain social progress and sustainable development. As one of the components in batteries, electrolytes play an important role in the upgrade and breakthrough of battery technology. Since room-temperature ionic liquids (ILs) feature high conductivity, nonflammability, nonvolatility, high thermal stability, and wide electrochemical window, they have been widely applied in various battery systems and show great potential in improving battery stability, kinetics performance, energy density, service life, and safety. Thus, it is a right time to summarize these progresses. In this review, the composition and classification of various ILs and their recent applications as electrolytes in diverse metal-ion batteries (Li, Na, K, Mg, Zn, Al) are outlined to enhance the battery performances.
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http://dx.doi.org/10.1002/advs.202004490DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8261505PMC
July 2021

Recent Progress in External-Stimulus-Responsive 2D Covalent Organic Frameworks.

Adv Mater 2021 Jul 8:e2101175. Epub 2021 Jul 8.

Department of Materials Science and Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong SAR, 999077, P. R. China.

Recently, smart 2D covalent organic frameworks (COFs), combining the advantages of both inherent structure features and functional building blocks, have been demonstrated to show reversible changes in conformation, color, and luminescence in response to external stimuli. This review provides a summary on the recent progress of 2D COFs that are responsive to external stimuli such as metal ions, gas molecules, pH values, temperature, electricity, light, etc. Moreover, the responsive mechanisms and design strategies, along with the applications of these stimulus-responsive 2D COFs in chemical sensors and photoelectronic devices are also discussed. It is believed that this review would provide some guidelines for designing novel single-/multistimulus-responsive 2D COFs with controllable responsive behaviors for advanced photoelectronic applications.
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http://dx.doi.org/10.1002/adma.202101175DOI Listing
July 2021

Hydrogen Bonding in Self-Healing Elastomers.

ACS Omega 2021 Apr 29;6(14):9319-9333. Epub 2021 Mar 29.

Department of Materials Science and Engineering City University of Hong Kong Kowloon, Hong Kong SAR 99880, China.

In the past decade, the self-healing elastomers based on multiple hydrogen bonding have attracted ample attention due to their rich chemical structures, adjustable mechanical properties, fast healing speed, and high healing efficiency. Through prolonging the service life and fast recovery of the mechanical properties, self-healing elastomers can be potentially applied in the field of wearable electronics, electronic skins, motion tracking, and health monitoring. In this perspective, we will introduce the concept and classification of self-healing materials first, then the hydrogen bonds, and the corresponding position of hydrogen-bonding units in the polymer structures. We will also conclude the potential application of hydrogen bonding-based elastomers. Finally, a summary and outlook will be provided.
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http://dx.doi.org/10.1021/acsomega.1c00462DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8047772PMC
April 2021

Toward Highly Robust Nonvolatile Multilevel Memory by Fine Tuning of the Nanostructural Crystalline Solid-State Order.

Small 2021 May 31;17(19):e2100102. Epub 2021 Mar 31.

Department of Materials Science and Engineering, City University of Hong Kong, Kowloon, Hong Kong SAR, 999077, China.

Organic resistive memory (ORM) offers great promise for next-generation high-density multilevel-cell (MLC) data storage. However, the fine tuning of crystalline order among its active layer still remains challenging, which largely restricts ORM behavior. Here, an exceptional solid-state transition from disordered orientations to highly-uniform orientation within the ORM layer is facilely triggered via molecular strategic tailoring. Two diketopyrrolopyrrole-based small molecular analogues (NI TDPP and NI TDPP) are demonstrated to display different symmetry. The asymmetric NI TDPP shows an irregular solid-state texture, while the centro-symmetric NI TDPP conforms to an ordered out-of-plane single-crystalline pattern that aligns with the foremost charge transportation along the substrate normal, and exhibits excellent MLC memory characteristics. Moreover, this highly oriented pattern guarantees the large-area film uniformity, leading to the twofold increase in the yield of as-fabricated ORM devices. This study reveals that the solid-state crystalline nanostructural order of organic materials can be controlled by reasonable molecular design to actuate high-performance organic electronic circuits.
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http://dx.doi.org/10.1002/smll.202100102DOI Listing
May 2021

Anthrathiadiazole Derivatives: Synthesis, Physical Properties and Two-photon Absorption.

Chemistry 2021 Jul 21;27(42):10898-10902. Epub 2021 Jun 21.

Department of Materials Science and Engineering, City University of Hongkong.

Anthrathiadiazole is a key synthon for the construction of large azaacenes, however, the attachment of different substituents onto the skeleton of anthrathiadiazole is difficult but highly desirable because it could be easy to enrich the structures of azaacenes. Here, it is demonstrated that anthrathiadiazole derivatives with -Br, -CN, and -OCH groups could be easily constructed through a simple [4+2] cycloaddition reaction between a,a,a',a'-tetrabromo-o-xylenes derivatives and benzo[c][1,2,5]thiadiazole-4,7-dione. The structures of the as-prepared compounds with different substituents were carefully characterized. Moreover, the basic physical properties of the as-prepared anthrathiadiazole derivatives were fully investigated, where the cyano-substituted derivative (BTH-CN) has the highest stability and the methoxy-substituted derivative (BTH-OCH ) is easy to be oxidized. Moreover, the two-photon absorption (TPA) characteristics of different anthrathiadiazoles are also studied by using the femtosecond Z-scan technique. The results show that the fused anthrathiadiazole skeletons possess large TPA cross-section values δ in the range of 3000-5000 GM, where the nature, position and strength of the substituted groups have strong effect on these values.
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http://dx.doi.org/10.1002/chem.202100307DOI Listing
July 2021

Fe-Based Coordination Polymers as Battery-Type Electrodes in Semi-Solid-State Battery-Supercapacitor Hybrid Devices.

ACS Appl Mater Interfaces 2021 Apr 24;13(13):15315-15323. Epub 2021 Mar 24.

Department of Materials Science and Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong SAR 999077, P. R. China.

One two-dimensional Fe-based metal-organic framework (FeSC1) and one one-dimensional coordination polymer (FeSC2) have been solvothermally prepared through the reaction among FeSO·7HO, the tripodal ligand 4,4',4″--triazine-2,4,6-triyl-tribenzoate (HTATB), and flexible secondary building blocks p/m-bis((1H-imidazole-1-yl)methyl)benzene (bib). Given that their abundant interlayer spaces and different coordination modes, two compounds have been employed as battery-type electrodes to understand how void space and different coordination modes affect their performances in three-electrode electrochemical systems. Both materials exhibit outstanding but different electrochemical performances (including distinct capacities and charge-transfer abilities) under three-electrode configurations, where the charge storage for each electrode material is mainly dominated by the diffusion-controlled section ( ∝ ) through power-law equations. Additionally, the partial phase transformations to more stable FeOOH are also detected in the long-term cycling loops. After coupling with the capacitive carbon-based electrode to assemble into the semi-solid-state battery-supercapacitor-hybrid (sss-BSH) devices, the sss-FeSC1//AC BSH device delivers excellent capacitance, superior energy and power density, and longstanding endurance as well as the potential practical property.
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http://dx.doi.org/10.1021/acsami.1c01339DOI Listing
April 2021

The gut microbiota during the progression of atherosclerosis in the perimenopausal period shows specific compositional changes and significant correlations with circulating lipid metabolites.

Gut Microbes 2021 Jan-Dec;13(1):1-27

School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, China.

Atherosclerosis (AS) is exacerbated in the perimenopausal period, which significantly increases the incidence rate of cardiovascular disease. The disruption of the gut microbiota has been associated with AS or menopause, but the specific changes of AS-associated gut microbiota in the perimenopausal period remain largely unknown. As lipid abnormalities are mainly responsible for AS, the relationship between lipid metabolism abnormalities and gut microbiota disruptions during menopause is rarely reported hitherto. In the present study, ApoE mice fed with a high-fat diet (HFD) were subjected to ovariectomy and supplemented with estrogen. The ovariectomized HFD-fed ApoE mice underwent significant AS damage, hepatic lipid damage, hyperlipidemia, and changes of lipid metabolism- and transport-related enzymes. There was significantly higher abundance of some lipid metabolites in the plasma of ovariectomized HFD-fed ApoE mice than in non-ovariectomized ones, including cholesterol esters, triglycerides, phospholipids, and other types of lipids (free fatty acids, acylcarnitine, sphingomyelins, and ceramides). The administration of estrogen significantly reduced the contents of most lipid metabolites. The diversity and composition of gut microbiota evidently changed in ovariectomized HFD-fed ApoE mice, compared to HFD-fed ApoE mice without ovariectomy. In contrast, with estrogen supplementation, the diversity and composition of gut microbiota were restored to approach that of non-ovariectomized HFD-fed ApoE mice, and the relative abundances of some bacteria were even like those of C57BL/6 mice fed with a normal diet. On the other hand, the transplantation of feces from C57BL/6 mice fed with normal diet to ovariectomized HFD-fed ApoE mice was sufficient to correct the hyperlipidemia and AS damage, and to reverse the characteristics changing of lipid metabolomics in ovariectomized HFD-fed ApoE mice. These phenomena were also been observed after transplantation of feces from estrogen-treated ovariectomized HFD-fed ApoE mice to ovariectomized HFD-fed ApoE mice. Moreover, the gut microbiota and lipid metabolites were significantly correlated, demonstrating that the changes of serum lipids may be associated with the gut microbiota disruptions in the perimenopausal period. In conclusion, the gut microbiota during the progression of AS in the perimenopausal period showed specific compositional changes and significant correlations with circulating lipid metabolites. Estrogen supplementation may exert beneficial effects on gut bacteria and lipid metabolism.
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http://dx.doi.org/10.1080/19490976.2021.1880220DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7954427PMC
March 2021

Cd bioavailability and nitrogen cycling microbes interaction affected by mixed amendments under paddy-pak choi continued planting.

Environ Pollut 2021 Apr 6;275:116542. Epub 2021 Feb 6.

Department of Soil, Water, & Climate, Univ. of Minnesota, 1991 Upper Buford Cir, Falcon Heights, MN, 55108, USA.

Cadmium (Cd) is the most concerning soil pollutant, and a threat to human health, especially in China. The in-situ immobilization of Cadmium by amendments is one of the most widely adopted methods to remedy soil contamination. The study was designed to evaluate the effect of organo-chemical amendments on soil Cd bioavailability and nitrogen cycling microbes under continuous planting of rice (Oryza sativa) and pak choi (Brassica chinensis L.). The experiment was carried out using four amendments, Lime, Zeolite, Superphosphate, and Biochar, at two different ratios; M1: at the ratio of 47:47:5:1, and M2 at the ratio of 71:23:5:1, respectively. Moreover, both M1 and M2 were enriched at four levels (T1: 0.5%; T2: 1%; T3: 2%; T4: 4%). Results showed that compared with CK (Cd enriched soils), the yield of rice under treatments of M1T1 and M2T1 increased by 8.93% and 8.36%, respectively. While the biomass (fresh weight) of pak choi under M1 and M2 amendments increased by 2.52-2.98 times and 0.76-2.89 times respectively, under enrichment treatments T1, T2, and T3. The total Cd concentrations in rice grains treated with M1T3 and M2T3 decreased by 89.25% and 93.16%, respectively, compared with CK. On the other hand, the total Cd concentrations in pak choi under M1T3 and M2T2 decreased by 92.86% and 90.23%, respectively. The results showed that soil pH was the main factor affecting Cd bioavailability in rice and pak choi. The Variance partitioning analysis (VPA) of rice and pak choi showed that soil pH was the most significant contributing factor. In the rice season, the contribution of soil pH (P) on Cd bioavailability was 10.14% (P = 0.102), and in the pak choi season, the contribution of soil pH was 8.38% (P = 0.133). Furthermore, the abundance of ammonia oxidation and denitrifying microorganisms had significantly correlation with soil pH and exchange Cd. In rice season, when the enrichment level of amendments increased from 0.5% (T1) to 2% (T3), the gene abundance of AOA, AOB, nirK, nirS and nosZ (І) tended to decrease. While in pak choi season, when the enrichment level increased at the level of 0.5% (T1), 1% (T2), and 2% (T3), the gene abundance of AOB, nirS, and nosZ (І) increased. Additionally, the gene abundance of AOA and nirK showed a reduction in the pak choi season contrasting to rice. And the mixed amendment M2 performed better at reducing Cd uptake than M1, which may have correlation with the ratio of lime and zeolite in them. Finally, we conclude that between these two amendments, when applied at a moderate level M2 type performed better than M1 in reducing Cd uptake, and also showed positive effects on both gene abundance and increase soil pH.
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http://dx.doi.org/10.1016/j.envpol.2021.116542DOI Listing
April 2021

synthesis of hierarchical [email protected](OH) heterostructures for enhanced pseudocapacitor and oxygen evolution reaction performances.

Dalton Trans 2021 Mar;50(8):3060-3066

College of Materials and Chemical Engineering, Key Laboratory of Inorganic Nonmetallic Crystalline and Energy Conversion Materials, China Three Gorges University, Yichang, 443002, P. R. China.

Integrating the merits of different components to construct heterostructures for energy storage and conversion has attracted intensive attention. Herein, taking advantage of bimetallic MOFs and transition bimetal hydroxide, we have successfully used nanoflower-like Ni1-xCox(OH)2 as both the precursor and template to in situ construct three dimensional (3D) [email protected](OH)2 (denoted as [email protected]) hierarchical heterostructures. Benefiting from the optimized composition with hierarchical heterostructures assembled by ultrathin nanosheets, [email protected] possesses rich effective active sites and high electrochemical reactivity, delivering superior pseudocapacitor performance with a specific capacitance of 1855.3 F g-1 at 2 A g-1 and good rate performance. Besides, [email protected] also exhibits excellent OER activity with small overpotentials of 193 mV and 310 mV at 10 and 100 mA cm-2, respectively.
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http://dx.doi.org/10.1039/d0dt03872eDOI Listing
March 2021

Non-Metal Ion Co-Insertion Chemistry in Aqueous Zn/MnO Batteries.

Angew Chem Int Ed Engl 2021 Mar 24;60(13):7056-7060. Epub 2021 Feb 24.

Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Renewable Energy Conversion and Storage Center, College of Chemistry, Nankai University, Tianjin, 300071, P. R. China.

The co-insertion of dual ions can often offer enhanced electrochemical performance for the aqueous zinc batteries. Although the insertion of non-metallic ions has been achieved in aqueous zinc batteries, the co-insertion chemistry of non-metallic cations is still a challenge. Here, a reversible H /NH co-insertion/extraction mechanism was developed in an aqueous Zn/MnO battery system. The synergistic effect between the dual cations endows the aqueous batteries with the fast kinetics of ion diffusion and the reversible structure evolution of MnO . As a result, the Zn/MnO battery displays excellent rate capability and cycling performance. This work will pave the way toward the design of aqueous rechargeable batteries with non-metallic ions.
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http://dx.doi.org/10.1002/anie.202017098DOI Listing
March 2021

Organic Materials as Electrodes in Potassium-Ion Batteries.

Chemistry 2021 Apr 8;27(20):6131-6144. Epub 2021 Feb 8.

Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong, 999077, P. R. China.

The integrated advantages of organic electrode materials and potassium metal make the organic potassium-ion batteries (OPIBs) promising secondary batteries. This review summarizes the latest research progress on OPIBs according to the different types of electrode materials (namely, organic small molecules compounds, polymers, and frameworks (metal-organic frameworks (MOFs), covalent organic frameworks (COFs)). Additionally, the research prospects and outlook for OPIBs are also provided.
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http://dx.doi.org/10.1002/chem.202005259DOI Listing
April 2021

Estrogen prevent atherosclerosis by attenuating endothelial cell pyroptosis via activation of estrogen receptor α-mediated autophagy.

J Adv Res 2021 Feb 24;28:149-164. Epub 2020 Aug 24.

School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China.

Excessive inflammation and the pyroptosis of vascular endothelial cells caused by estrogen deficiency is one cause of atherosclerosis in post-menopausal women. Because autophagy is highly regulated by estrogen, we hypothesized that estrogen can reduce vascular endothelial cell pyroptosis through estrogen receptor alpha (ERα)-mediated activation of autophagy to improve atherosclerosis in post-menopausal stage. Aortic samples from pro-menopausal and post-menopausal women with ascending aortic arteriosclerosis were analyzed, and bilateral ovariectomized (OVX) female ApoE-/- mice and homocysteine (Hcy)-treated HUVECs were used to analyze the effect of estrogen supplementation therapy. The aortic endothelium showed a decrease in ERα expression and autophagy, but presented an increase in inflammation and pyroptosis in female post-menopausal patients. Estrogen treatment accelerated autophagy and ameliorated cell pyroptosis in the cardiac aortas of OVX ApoE-/- mice and Hcy-treated HUVECs. Estrogen had therapeutic effect on atherosclerosis and improved the symptoms associated with lipid metabolism disorders in OVX ApoE-/- mice. Inhibition and silencing of ERα led to a reduction in the autophagy promoting ability of estrogen and aggravated pyroptosis. Moreover, the inhibition of autophagy promoted pyroptosis and abolished the protective effect of estrogen, but had no influence on ERα expression. Thus, the results of the present study demonstrated that post-menopausal women present decreased autophagy and ERα expression and excessive damage to the ascending aorta. In addition, and assay results demonstrated that estrogen prevents atherosclerosis by upregulating ERα expression and subsequently induces autophagy to reduce inflammation and pyroptosis.
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http://dx.doi.org/10.1016/j.jare.2020.08.010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7753237PMC
February 2021

Recent Progress in Polycyclic Aromatic Hydrocarbon-Based Organic Co-Crystals.

Chem Rec 2021 Jan 10;21(1):116-132. Epub 2020 Nov 10.

Department of Materials Science and Engineering, City University of Hong Kong, Kowloon, Hong Kong postCode/>999077, China.

Recently, the development of polycyclic aromatic hydrocarbon (PAH)-based organic co-crystals has attracted increasing interest due to their unique packing modes, optic-electronic properties and various potential applications in electronic, optic-electronic and magnetic devices. In this account, we mainly discuss the definition, classification, packing patterns, preparation methods, and applications of PAH-based co-crystals. Specifically, the main categories of PAH-based organic co-crystals, the frequent methods to prepare them, three main packing patterns, their optical and electrical properties, and their potential applications will be presented. Finally, an outlook of this field is provided.
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http://dx.doi.org/10.1002/tcr.202000098DOI Listing
January 2021

Electrochromic two-dimensional covalent organic framework with a reversible dark-to-transparent switch.

Nat Commun 2020 Nov 2;11(1):5534. Epub 2020 Nov 2.

School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore.

Electrochromic (EC) materials with a dark-to-transmissive switch have great applications in optical communications, infrared wavelength detectors for spacecraft, and infrared camouflage coatings. However, such electroactive materials with high stability and cyclability are rare. Considering the advantages of the donor-acceptor approach (wide-range tuneable band position) and porous two-dimensional (2D) covalent organic framework (COF, well-ordered crystalline framework with stable structure and high surface area), in this work we constructed an extended delocalised π-electron layered dark purple EC-COF-1 by reacting the donor N,N,N',N'-tetrakis(p-aminophenyl)-p-benzenediamine (TPBD) with the acceptor 2,1,3-benzothiadiazole-4,7-dicarboxaldehyde (BTDD). A sandwiched device made of EC-COF-1 exhibits the two-band bleaching (370 nm and 574 nm) in the visible region and becomes transparent under the applied potential with an induced absorption centring at 1400 nm. This discovery of a stable dark-to-transmissive switch in COF might open another door for their application in many EC devices for various purposes.
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http://dx.doi.org/10.1038/s41467-020-19315-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7608553PMC
November 2020

Green Grinding-Coassembly Engineering toward Intrinsically Luminescent Tetracene in Cocrystals.

ACS Nano 2020 11 28;14(11):15962-15972. Epub 2020 Oct 28.

School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore.

Developing an effective and green method toward organic functional cocrystals based on the solubility-mismatched coformers is highly desirable and very important. Herein, we applied a green two-step liquid-assisted-grinding coassembly (LAGC) in fabricating tetracene-octafluoronaphthalene (TC-OFN) cocrystals from solubility-mismatched pairs of tetracene (TC, poorly soluble, 0.2 mg mL) and octafluoronaphthalene (OFN, highly soluble, 0.2 × 10 mg mL). Such cocrystals are extremely difficult to prepare through the common solution-processing strategies. More importantly, this two-step LAGC process could allow us to efficiently prepare TC-OFN cocrystals in gram scale. The as-prepared cocrystals displayed the intrinsic green emission of TC with much higher photoluminescence quantum yield (13.75%) comparing with the pure solid TC with the almost-quenched emission (0.41%, aggregation-caused quenching (ACQ)). The ultrafast spectra study on these cocrystals verifies the successful barrier function of OFN molecules in interrupting the well-known singlet fission (SF) in TC solids. Furthermore, this method can allow us to easily fabricate fluorescent TC-OFN water inks, which can be employed to prepare luminescent paintings or highly emissive ultratransparent/flexible films.
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http://dx.doi.org/10.1021/acsnano.0c07416DOI Listing
November 2020

Bis(thieno[3,2-]thieno)cyclopentafluorene-Based Acceptor with Efficient and Comparable Photovoltaic Performance under Various Processing Conditions.

ACS Appl Mater Interfaces 2020 Nov 22;12(44):49876-49885. Epub 2020 Oct 22.

School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.

The morphology of a bulk heterojunction (BHJ) blend within a polymer solar cell (PSC) device plays a crucial role in its performance. The ideal morphology is generally achieved through molecular engineering and optimization under film processing conditions. Under different processing conditions, the deviation of the resulted morphology characteristics from the ideal one leads to the dispersion of device performance. For a specific donor/acceptor BHJ blend, it is of great challenge to maintain an efficient and comparable photovoltaic performance under various processing conditions. The solution to this challenge would be of great value in offering more choices for a suitable processing technology in practical applications. Based on the acceptor BTTFIC with the core of bis(thieno[3,2-]thieno)cyclopentafluorene (BTTF) in our previous work, we chemically modified BTTFIC by fluorination of the end groups of 1,1-dicyanomethylene-3-indanones (IC) and the switching part of octyls in BTTF with 4-hexylphenyls to offer a novel acceptor (BTTFIC4F-Ar). The inverted PBDB-T-2Cl:BTTFIC4F-Ar blend device provided an average power conversion efficiency (PCE) of 10.61, 11.08, and 11.55% when processed under solvent annealing (SA), thermal annealing (TA), and additive treatment with 1,8-diodooctane (DIO), respectively. Different from the reported discrete performance under various processing conditions for a specific donor/acceptor BHJ blend, a low mean absolute performance deviation of 3% was attained. This slight enhancement trend was unexceptionally reflected on charge generation, transportation, and recombination within the blend films from SA, TA, and DIO conditions. A slightly improved ordering of BTTFIC4F-Ar within the DIO blend was observed. Meanwhile, very similar molecular packings as well as a close amorphous domain size of the mixture of PBDB-T-2Cl and BTTFIC4F-Ar within the three blends were observed. These morphological characteristics are in good agreement with the photoelectrical conversion performance of the blends under the three processing conditions. Furthermore, similar attenuation behaviors in performance were also observed. This investigation may provide new guidance on the molecular engineering of nonfullerene acceptors to achieve an efficient BHJ blend with more options for a suitable and cost-effective processing method in practical applications.
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http://dx.doi.org/10.1021/acsami.0c13109DOI Listing
November 2020

Enhancing the Performance of a Battery-Supercapacitor Hybrid Energy Device Through Narrowing the Capacitance Difference Between Two Electrodes via the Utilization of 2D MOF-Nanosheet-Derived [email protected] Core-Shell Rings as Both Negative and Positive Electrodes.

ACS Appl Mater Interfaces 2020 Oct 7;12(42):47482-47489. Epub 2020 Oct 7.

School of Materials Science & Engineering, Nanyang Technological University, Singapore 639678, Singapore.

Narrowing the capacitance gap between the positive and negative electrodes for the enhancement of the energy densities of battery-supercapacitor hybrid (BSH) devices is urgent and very important. Herein, a new strategy to synchronously improve the positive-negative system and reduce the capacitance discrepancies between two electrodes through the utilization of the same MOF-based precursors ([Ni(ATA)(HO)](HO)) has been proposed. Nickel/nitrogen codoped carbon ([email protected]) materials, serving as positive electrodes, deliver battery-type behavior with the enhancement of capacities, which are even superior to those of pristine carbon-based materials with large surface areas. Meanwhile, HCl-treated [email protected] materials (named [email protected]) are employed as negative electrodes within the potential window of -1 to 0 V and exhibit higher capacitances than that of the commercial activated carbon. With [email protected] and [email protected] as positive and negative electrodes in BSH devices, the as-fabricated cells display higher capacities and energy densities, more excellent cycling stability, and far superior capacity retention in comparison with those of [email protected]//AC cells. These results clearly confirm that our strategy is successful and effective.
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http://dx.doi.org/10.1021/acsami.0c12830DOI Listing
October 2020

Performance and mechanisms for remediation of Cd(II) and As(III) co-contamination by magnetic biochar-microbe biochemical composite: Competition and synergy effects.

Sci Total Environ 2021 Jan 13;750:141672. Epub 2020 Aug 13.

College of Environmental Natural Resource Sciences, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Hangzhou 310058, China. Electronic address:

Contaminations by heavy metals in the environment always exist as a mixture of both metal and metalloid. Thus, it is a challenge to simultaneously remove both components due to their adverse chemical behaviors. Herein, effective cadmium (Cd) and arsenic (As) removal in aqueous solution was achieved by use of a novel composite, which was synthesized by Bacillus sp. K1 loaded onto FeO biochar (MBB). The combination with Bacillus sp. K1 provided new biosorption sites such as amine and hydroxyl groups in the composite surface, which significantly increasing the removal capability of Cd(II) by 230% when compared with the raw magnetic biochar. Both competition and synergy effects were found in binary system. Adsorption of As(III) extended active sites for capturing Cd(II), which appeared on the surface of the MBB as type B ternary surface complexes. The maximum adsorption capacity of Cd(II) and As(III) reached 25.04 and 4.58 mg g in a binary system, respectively. In summary, this environmentally friendly composite is promising for simultaneous Cd(II) and As(III) remediation.
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http://dx.doi.org/10.1016/j.scitotenv.2020.141672DOI Listing
January 2021

Highly Conductive Two-Dimensional Metal-Organic Frameworks for Resilient Lithium Storage with Superb Rate Capability.

ACS Nano 2020 Sep 1;14(9):12016-12026. Epub 2020 Sep 1.

Centre for Clean Environment and Energy, School of Environment and Science, Gold Coast Campus, Griffith University, Brisbane, Queensland 4222, Australia.

Redox-active organic cathode materials have drawn growing attention because of the broad availability of raw materials, eco-friendliness, scalable production, and diverse structural flexibility. However, organic materials commonly suffer from fragile stability in organic solvents, poor electrochemical stability in charge/discharge processes, and insufficient electrical conductivity. To address these issues, using Cu(II) salt and benzenehexathiolate (BHT) as the precursors, we synthesized a robust and redox-active 2D metal-organic framework (MOF), [Cu(CS)], namely, Cu-BHT. The Cu-BHT MOFs have a highly conjugated structure, affording a high electronic conductivity of 231 S cm, which could further be increased upon lithiation in lithium-ion battery (LIB) applications. A reversible four-electron reaction reveals the Li storage mechanism of the Cu-BHT for a theoretical capacity of 236 mAh g. The as-prepared Cu-BHT cathode delivers an excellent reversible capacity of 175 mAh g with ultralow capacity deterioration (0.048% per cycle) upon 500 cycles at a high current density of 300 mA g. Therefore, we believe this work would provide a practical strategy for the development of high-power energy storage materials.
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http://dx.doi.org/10.1021/acsnano.0c05200DOI Listing
September 2020

Immobilization of exchangeable Cd in soil using mixed amendment and its effect on soil microbial communities under paddy upland rotation system.

Chemosphere 2021 Jan 31;262:127828. Epub 2020 Jul 31.

Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, Zhejiang University, Hangzhou, 310058, PR China.

Cadmium (Cd) pollution is a widespread environmental problem that decreases crop production, destroys the microbial ecology of soil, and poses a severe risk to human health. Organo-chemical amendment is a cost-effective, eco-friendly, and community-acceptable widely applied an in situ technique for metal-contaminated farmland. In this study, we mixed lime, zeolite, calcium magnesium phosphate fertilizer, and biochar in a mixture ratio of 71:23:5:1 to form a mixed amendment. Field and laboratory experiments were conducted to study the effects of the mixed amendment on soil exchangeable Cd content, plant Cd accumulation, and soil microbial community. It was found that the application of 0.5% mixed amendment decreased exchangeable soil Cd by more than 85% and 64% in wheat and rice season, respectively, compared with control (CK), without increasing pH. Moreover, the application of 0.5% mixed amendment decreased Cd accumulation in grains by 22.9% and 41.2% in wheat and rice season, respectively, compared to CK. The result of phospholipid fatty acids (PLFAs) shows that the level of soil microbial diversity and species richness under mixed amendment treatments were higher than in lime treatment, indicating more copiotrophic conditions and faster rate of nutrient turnover in mixed amendment than pure lime treatment. Hence, it concluded that the mixed amendment has a strong effect on fixing exchangeable soil Cd and reducing the accumulation of Cd in crops. Finally, it was observed that the mixed amendment improved the soil microbial community structure and accelerate the rate of nutrient turnover by microbes under this favorable condition comparative to individual treatments.
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http://dx.doi.org/10.1016/j.chemosphere.2020.127828DOI Listing
January 2021

β-estradiol adjusts intestinal function via ERβ and GPR30 mediated PI3K/AKT signaling activation to alleviate postmenopausal dyslipidemia.

Biochem Pharmacol 2020 10 3;180:114134. Epub 2020 Jul 3.

School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China; Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China. Electronic address:

Decreases in estrogen secretion and estrogen receptor function lead to an increase in the incidence of dyslipidemia and cardiovascular disease (CVD) in postmenopausal women. We previously reported that β-estradiol has a significant regulatory effect on lipids in ApoE mice with bilateral ovariectomy. In the present study, we investigated how β-estradiol regulates intestinal function via estrogen receptors to alleviate postmenopausal dyslipidemia. Ovariectomized ApoE mice were treated with β-estradiol for 90 days, and we found that β-estradiol reduced TC, TG, LDL-c, IL-1β and IL-18 levels in serum and decreased lipid accumulation in the liver. β-estradiol reduced injury and inflammation in the jejunum in ovariectomized mice, and promoted the expression of tight junction-related proteins. Moreover, β-estradiol increased ERα, ERβ, GPR30 and ABCG5 protein expression, and decreased the levels of NPC1L1 and SR-B1 in the jejunum of ovariectomized mice. In Caco-2 cells incubated with cholesterol, β-estradiol up-regulated PI3K/AKT signaling, reduced cholesterol accumulation, suppressed inflammatory signaling, and increased the expression of tight junction-related proteins. ERβ or GPR30 inhibition decreased the protective effect of β-estradiol on cholesterol accumulation, tight junctions, and inflammation in cholesterol incubated Caco-2 cells, while silencing both ERβ and GPR30 completely eliminated the protective effect of β-estradiol. PI3K/AKT inhibition abolished the protective effect of β-estradiol on cholesterol accumulation, tight junction-related protein expression, and inflammation, but had no influence on ERα, ERβ or GPR30 expression in cholesterol incubated Caco-2 cells. Our results provide evidence that β-estradiol regulates intestinal function via ERβ and GPR30 mediated PI3K/AKT signaling activation to alleviate postmenopausal dyslipidemia.
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http://dx.doi.org/10.1016/j.bcp.2020.114134DOI Listing
October 2020

Multifunctional Features of Organic Charge-Transfer Complexes: Advances and Perspectives.

Chemistry 2021 Jan 5;27(2):464-490. Epub 2020 Nov 5.

School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore.

The recent progress of charge-transfer complexes (CTCs) for application in many fields, such as charge transport, light emission, nonlinear optics, photoelectric conversion, and external stimuli response, makes them promising candidates for practical utility in pharmaceuticals, electronics, photonics, luminescence, sensors, molecular electronics and so on. Multicomponent CTCs have been gradually designed and prepared as novel organic active semiconductors with ideal performance and stability compared to single components. In this review, we mainly focus on the recently reported development of various charge-transfer complexes and their performance in field-effect transistors, light-emitting devices, lasers, sensors, and stimuli-responsive behaviors.
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http://dx.doi.org/10.1002/chem.202002640DOI Listing
January 2021

Rational Control of Charge Transfer Excitons Toward High-Contrast Reversible Mechanoresponsive Luminescent Switching.

Angew Chem Int Ed Engl 2020 Sep 11;59(40):17580-17586. Epub 2020 Aug 11.

School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore.

A practicable strategy to rationally obtain the reversible mechanochromic luminescent (MCL) material with high-contrast ratio (green versus red) has been established. By introducing a volatile third party (small-sized solvent molecules) into the lattice of charge transfer (CT) cocrystal of mixed-stacking 1:1 coronene (Cor.) and napthalenetetracarboxylic diimide (NDI), a noteworthy reconfigurable molecular assembly is ingeniously achieved owing to the loosely packing arrangement as well as weakened intermolecular interactions. Accordingly, the CT excited state, strongly corresponding to the molecular stacking modes, can be intentionally tailored through external stimulus (heating, grinding, or solvent), accompanying distinct changes in photophysical properties. Subsequently, a high-contrast reversible MCL with highly sensitive and good reproducibility is realized and the underlying mechanism is thoroughly revealed.
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http://dx.doi.org/10.1002/anie.202005933DOI Listing
September 2020

Ferrocene-Based Mixed-Valence Metal-Organic Framework as an Efficient and Stable Cathode for Lithium-Ion-Based Dual-Ion Battery.

ACS Appl Mater Interfaces 2020 Jul 10;12(29):32719-32725. Epub 2020 Jul 10.

School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore.

Organic anion-hosting cathodes are remarkably attractive platform candidates for lithium-ion-based dual-ion batteries (LDIBs) due to their various advantages such as variety, designable, and adjustable. Here, a new organic anion-hosting mixed-valence metal-organic framework cathode (CoCo(DFc)(OH)·HO, abbreviated as Co(DFc)x) is first employed in LDIBs. With the redox reactions happening in the couples of Fe/Fe and Co/Co, PF anions can be incorporated into the cathode and reversibly released into the LiPF-based electrolyte. Meanwhile, benefiting from its unique structure and insolubility, Co(DFc)x shows a high energy density of 632 Wh kg (vs lithium anode), a high operating potential of 3.63 V (vs Li/Li), a high reversible (discharge) capacity of 170 mAh g at 50 mA g (the third cycle), an excellent rate performance (up to 2000 mA g, 5 min for one cycle), and extraordinary cycling stability (an average capacity of 74.9 mAh g for 8000 cycles at 2000 mA g).
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http://dx.doi.org/10.1021/acsami.0c07729DOI Listing
July 2020

Recent Progress in High Linearly Fused Polycyclic Conjugated Hydrocarbons (PCHs, > 6) with Well-Defined Structures.

Adv Sci (Weinh) 2020 Jun 22;7(12):1903766. Epub 2020 Apr 22.

School of Materials Science and Engineering Nanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore.

Although polycyclic conjugated hydrocarbons (PCHs) and their analogues have gained great progress in the fields of organic photoelectronic materials, the in-depth study on present PCHs is still limited to hexacene or below because longer PCHs are insoluble, unstable, and tediously synthesized. Very recently, various strategies including on-surface synthesis are developed to address these issues and many higher novel PCHs are constructed. Therefore, it is necessary to review these advances. Here, the recent synthetic approach, basic physicochemical properties, single-crystal packing behaviors, and potential applications of the linearly fused PCHs (higher than hexacene), including acenes or π-extended acenes with fused six-membered benzenoid rings and other four-membered, five-membered or even seven-membered and eight-membered fused compounds, are summarized.
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http://dx.doi.org/10.1002/advs.201903766DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7312318PMC
June 2020

2D Metal-Organic Frameworks (MOFs) for High-Performance BatCap Hybrid Devices.

Small 2020 Jul 25;16(30):e2001987. Epub 2020 Jun 25.

School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639678, Singapore.

Two identical layered metal-organic frameworks (MOFs) (CoFRS and NiFRS) are constructed by using flexible 1,10-bis(1,2,4-triazol-1-yl)decane as pillars and 1,4-benzenedicarboxylic acid as rigid linkers. The single-crystal structure analysis indicates that the as-synthesized MOFs possess fluctuant 2D networks with large interlayer lattices. Serving as active electrode elements in supercapacitors, both MOFs deliver excellent rate capabilities, high capacities, and longstanding endurances. Moreover, the new intermediates in two electrodes before and after long-lifespan cycling are also examined, which cannot be identified as metal hydroxides in the peer reports. After assembled into battery-supercapacitor (BatCap) hybrid devices, the NiFRS//activated carbon (AC) device displays better electrochemical results in terms of gravimetric capacitance and cycling performance than CoFRS//AC devices, and a higher energy-density value of 28.7 Wh kg compared to other peer references with MOFs-based electrodes. Furthermore, the possible factors to support the distinct performances are discussed and analyzed.
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http://dx.doi.org/10.1002/smll.202001987DOI Listing
July 2020

Improved stability and efficiency of polymer-based selenium solar cells through the usage of tin(iv) oxide in the electron transport layers and the analysis of aging dynamics.

Phys Chem Chem Phys 2020 Jul;22(26):14838-14845

School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore. and Department of Materials Science and Engineering, City University of Hong Kong, Kowloon, Hong Kong SAR, China.

Recently, in the arena of finding substitutes for lead-containing perovskite solar cells, the oldest selenium solar cells (SSCs) have been reconsidered by many scientists due to their suitable energy level structure and less-toxic nature. A lot of research efforts have been made to improve the efficiency of SSCs through seeking suitable substrates and modifying the process of Se crystallization. However, little attention has been paid to investigating the stability of SSCs. In addition, one crucial point that is neglected by researchers could be the potential applications of low-cost SSCs in complicated and tough environments, owing to the intrinsic physicochemical resistance of the Se material. To address these issues, in this research, SSCs with an elaborately designed architecture have been presented, and the highest efficiency (3.7%) among SSCs with organic hole transport layers was achieved. Additionally, a dozen of P3HT-based SSCs were demonstrated to maintain 92% efficiency after more than 1500 hours. The favorable long-term stability of the SSCs allowed us to carefully analyze the changes in each dynamic parameter during aging and helped explore the factors that affect the device behaviors. These results would pave the way for the application of the ultra-stable SSCs in harsh conditions.
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http://dx.doi.org/10.1039/d0cp02367aDOI Listing
July 2020

Butterfly-like Tetraazaacenequinodimethane Derivatives: Synthesis, Structure and Halochromic Properties.

Chem Asian J 2020 Jul 17;15(14):2198-2202. Epub 2020 Jun 17.

School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore.

Two novel molecules TAP and TAH with pronounced reversible halochromic properties have been synthesized and fully characterized. Their butterfly-like structures have been confirmed through single-crystal X-ray diffraction. Their UV-Vis absorption after protonation dramatically red-shifted with naked-eye-visible color change in a very dilute concentration of 10 M. Note that the original color of the solution can be recovered after the neutralization with a base.
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http://dx.doi.org/10.1002/asia.202000587DOI Listing
July 2020
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