Publications by authors named "Xi Fan"

25 Publications

  • Page 1 of 1

Solution-Processed Transparent Conducting Electrodes for Flexible Organic Solar Cells with 16.61% Efficiency.

Nanomicro Lett 2021 Jan 4;13(1):44. Epub 2021 Jan 4.

Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institution of Chemistry, Chinese Academy of Sciences, Beijing, 100190, People's Republic of China.

Nonfullerene organic solar cells (OSCs) have achieved breakthrough with pushing the efficiency exceeding 17%. While this shed light on OSC commercialization, high-performance flexible OSCs should be pursued through solution manufacturing. Herein, we report a solution-processed flexible OSC based on a transparent conducting PEDOT:PSS anode doped with trifluoromethanesulfonic acid (CFSOH). Through a low-concentration and low-temperature CFSOH doping, the conducting polymer anodes exhibited a main sheet resistance of 35 Ω sq (minimum value: 32 Ω sq), a raised work function (≈ 5.0 eV), a superior wettability, and a high electrical stability. The high work function minimized the energy level mismatch among the anodes, hole-transporting layers and electron-donors of the active layers, thereby leading to an enhanced carrier extraction. The solution-processed flexible OSCs yielded a record-high efficiency of 16.41% (maximum value: 16.61%). Besides, the flexible OSCs afforded the 1000 cyclic bending tests at the radius of 1.5 mm and the long-time thermal treatments at 85 °C, demonstrating a high flexibility and a good thermal stability.
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http://dx.doi.org/10.1007/s40820-020-00566-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8187532PMC
January 2021

Hierarchically Microstructure-Bioinspired Flexible Piezoresistive Bioelectronics.

ACS Nano 2021 Jun 15. Epub 2021 Jun 15.

Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, P. R. China.

The naturally microstructure-bioinspired piezoresistive sensor for human-machine interaction and human health monitoring represents an attractive opportunity for wearable bioelectronics. However, due to the trade-off between sensitivity and linear detection range, obtaining piezoresistive sensors with both a wide pressure monitoring range and a high sensitivity is still a great challenge. Herein, we design a hierarchically microstructure-bioinspired flexible piezoresistive sensor consisting of a hierarchical polyaniline/polyvinylidene fluoride nanofiber (HPPNF) film sandwiched between two interlocking electrodes with microdome structure. Ascribed to the substantially enlarged 3D deformation rates, these bioelectronics exhibit an ultrahigh sensitivity of 53 kPa, a pressure detection range from 58.4 to 960 Pa, a fast response time of 38 ms, and excellent cycle stability over 50 000 cycles. Furthermore, this conformally skin-adhered sensor successfully demonstrates the monitoring of human physiological signals and movement states, such as wrist pulse, throat activity, spinal posture, and gait recognition. Evidently, this hierarchically microstructure-bioinspired and amplified sensitivity piezoresistive sensor provides a promising strategy for the rapid development of next-generation wearable bioelectronics.
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http://dx.doi.org/10.1021/acsnano.1c01606DOI Listing
June 2021

Reading development at the text level: an investigation of surprisal and embeddingbased text similarity effects on eyemovements in Chinese early readers.

Authors:
Xi Fan Ronan Reilly

J Eye Mov Res 2020 Sep 9;13(6). Epub 2020 Sep 9.

This paper describes the use of semantic similarity measures based on distributed representations of words, sentences, and paragraphs (so-called "embeddings") to assess the impact of supra-lexical factors on eye-movement data from early readers of Chinese. In addition, we used a corpus-based measure of surprisal to assess the impact of local word predictability. Eye movement data from 56 Chinese students were collected (a) in the students' 4th grade and (b) one year later while they were in 5th grade. Results indicated that surprisal and some text similarity measures have a significant impact on the momentto- moment processing of words in reading. The paper presents an easy-to-use set of tools for linking the low-level aspects of fixation durations to a hierarchy of sentence-level and paragraph-level features that can be computed automatically. The study is the first attempt, as far as we are aware, to track the developmental trajectory of these influences in developing readers across a range of reading abilities. The similarity-based measures described here can be used (a) to provide a measure of reader sensitivity to sentence and paragraph cohesion and (b) to assess specific texts for their suitability for readers of different reading ability levels.
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http://dx.doi.org/10.16910/jemr.13.6.2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8012104PMC
September 2020

The Diversity of the Intestinal Flora Disturbed After Feeding Intolerance Recovery in Preterm Twins.

Front Pediatr 2021 10;9:648979. Epub 2021 Mar 10.

Department of Neonatology, The First Affiliated Hospital of Jinan University, Guangzhou, China.

Feeding intolerance (FI) is a common condition in premature infants that results in growth retardation and even necrotizing enterocolitis. The gut microbiome is linked to FI occurrence; however, the outcome after FI recovery is unclear. Fecal samples were collected from 11 pairs of premature twins/triplets for 16S rRNA gene sequencing. Initial fecal samples were collected shortly after admission, and then every other week until 7 weeks or discharge. After FI recovery, there was no significant difference in the β-diversity of the intestinal flora between the FI group and the feeding tolerance (FT) group. By contrast, there was a significant difference in the β-diversity. Proteobacteria was the predominant phylum in the microbiome of the FI group, whereas Firmicutes was the predominant phylum in the microbiome of the FT group. The predominant bacteria with LDA >4 between the two groups at 13-15 days after birth, 19-28 days after birth, and at discharge were different, with the proportions of Bacillus, Clostridium butyricum, and Clostridium being highest in the FT group and Firmicutes, unidentified_Clostridiales, and Proteobacteria being highest in the FI group. Similarly, there were significant differences in the relative abundances of KEGG pathways, such as fatty acid metabolism, DNA repair and recombination proteins, energy metabolism, and amino acid metabolism, between the two groups ( < 0.01). There was a significant difference in diversity of the intestinal flora after feeding intolerance recovery. Feeding intolerance may disturb the succession of the intestinal bacterial community.
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http://dx.doi.org/10.3389/fped.2021.648979DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8006277PMC
March 2021

Threefold Collaborative Stabilization of Ag -Nanorods by Hydrophobic Ti -Oxo Clusters and Alkynes: Designable Assembly and Solid-State Optical-Limiting Application.

Angew Chem Int Ed Engl 2021 Jun 28;60(23):12949-12954. Epub 2021 Apr 28.

State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, 350002, Fuzhou, P. R. China.

Ag nanoclusters have received increasing attention due to their atomically precise and diverse structures and intriguing optical properties. Nevertheless, the inherent instability of Ag nanoclusters has seriously hindered their practical application. In this work, for the first time, Ag clusters are collaboratively protected by hydrophobic Ti-oxo clusters and alkyne ligands. Initially, a pyramidal Ag cluster terminated with BuC≡C and CH CN was inserted into the cavity of a Ti -oxo nanoring to form Ag @Ti . To overcome the instability of acetonitrile-terminated silver site, such two Ag @Ti clusters could sandwich an Ag unit to form Ag [email protected] -oxo-nanoring (Ag @Ti ), which is peripherally protected by fluorophenyl groups and alkyne caps. This threefold protected (hydrophobic fluorinated organic layer, Ti-O shell, and terminal alkyne ligands) Ag @Ti exhibits superhydrophobicity and excellent ambient stability, endowing it with solid-state optical limiting characteristics.
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http://dx.doi.org/10.1002/anie.202101664DOI Listing
June 2021

[Progress of researches on electrical characteristics of meridians and acupoints in recent 10 years].

Zhen Ci Yan Jiu 2020 Jan;45(1):77-82

College of Acupuncture and Moxibustion, Hebei University of Chinese Medicine, Shijiazhuang 050200, China.

The electrical characteristics of meridians and acupoints have been being one of the hot topics discussed by scholars, because of many influencing factors and inconsistent research results. In the present article, we collected papers published in Chinese or English in recent 10 years from PubMed, CNKI, and VIP databases by using key words of"acupuncture""meridian""resistance""capacitance""electrodermal"and"impedance". Then, we make an analysis about its development from three aspects, 1) manifestations of electrical properties of acupoints (low dermal resistance under pathological state, imbalance between left and right sides of the synonym acupoints), 2) clinical application of acupoint electrical characteristics for diagnosis of clinical disorders and evaluation of therapeutic effect, and 3) current situations of development of meridian detection instruments based on electrical characteristics (improving stability of instruments,expansion of the detected regions and measuring time, realization of visualization, and operational automation). In the process of coming studies, we highly recommend that more attention should be paid to the acupoints' "dynamic changes", and forming a standardized research plan, strengthening domestic and international academic exchanges and cooperation are definitely necessary in order to validate the objectivity and specificity of electrical characteristics of meridians and acupoints, further expanding its clinical application.
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http://dx.doi.org/10.13702/j.1000-0607.1808286DOI Listing
January 2020

cRGD-Conjugated [email protected] Multifunctional Nanocomposites for MRI and Antitumor Chemo-Photothermal Therapy.

Int J Nanomedicine 2019 5;14:9631-9645. Epub 2019 Dec 5.

Interventional Cancer Institute of Chinese Integrative Medicine, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, People's Republic of China.

Background: Photothermal therapy (PTT) has great potential in the clinical treatment of tumors. However, most photothermal materials are difficult to apply due to their insufficient photothermal conversion efficiencies (PCEs), poor photostabilities and short circulation times. Furthermore, tumor recurrence is likely to occur using PTT only. In the present study, we prepared cyclo (Arg-Gly-Asp-d-Phe-Cys) [c(RGD)] conjugated doxorubicin (DOX)-loaded [email protected] (PDA) nanoparticles to develop a multifunctional-targeted nanocomplex for integrated tumor diagnosis and treatment.

Materials And Methods: Cytotoxicity of [email protected] against HCT-116 cells was determined by cck-8 assay. Cellular uptake was measured by confocal laser scanning microscope (CLSM). Pharmacokinetic performance of DOX was evaluated to compare the differences between free DOX and DOX in nanocarrier. Performance in magnetic resonance imaging (MRI) and antitumor activity of complex nanoparticles were evaluated in tumor-bearing nude mice.

Results: [email protected] has a particle size of 200-300 nm and a zeta potential of 22.7 mV. Further studies in vitro and in vivo demonstrated their excellent capacity to target tumor cells and promote drug internalization, and significantly higher cytotoxicity with respect to that seen in a control group was shown for the nanoparticles. In addition, they have good thermal stability, photothermal conversion efficiencies (PCEs) and pH responsiveness, releasing more DOX in a mildly acidic environment, which is very conducive to their chemotherapeutic effectiveness in the tumor microenvironment. [email protected] NPs were used in a subcutaneous xenograft tumor model of nude mouse HCT-116 cells showed clear signal contrast in T2-weighted images and effective anti-tumor chemo-photothermal therapy under NIR irradiation.

Conclusion: According to our results, [email protected] had a satisfactory antitumor effect on colon cancer in nude mice and could be further developed as a potential integrated platform for the diagnosis and treatment of cancer to improve its antitumor activity against colon cancer.
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http://dx.doi.org/10.2147/IJN.S222797DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6901060PMC
February 2020

PEDOT:PSS for Flexible and Stretchable Electronics: Modifications, Strategies, and Applications.

Adv Sci (Weinh) 2019 Oct 30;6(19):1900813. Epub 2019 Jul 30.

Ningbo Institute of Materials Technology and Engineering Chinese Academy of Sciences Ningbo 315201 China.

Substantial effort has been devoted to both scientific and technological developments of wearable, flexible, semitransparent, and sensing electronics (e.g., organic/perovskite photovoltaics, organic thin-film transistors, and medical sensors) in the past decade. The key to realizing those functionalities is essentially the fabrication of conductive electrodes with desirable mechanical properties. Conductive polymers (CPs) of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) have emerged to be the most promising flexible electrode materials over rigid metallic oxides and play a critical role in these unprecedented devices as transparent electrodes, hole transport layers, interconnectors, electroactive layers, or motion-sensing conductors. Here, the current status of research on PEDOT:PSS is summarized including various approaches to boosting the electrical conductivity and mechanical compliance and stability, directly linked to the underlying mechanism of the performance enhancements. Along with the basic principles, the most cutting edge-progresses in devices with PEDOT:PSS are highlighted. Meanwhile, the advantages and plausible problems of the CPs and as-fabricated devices are pointed out. Finally, new perspectives are given for CP modifications and device fabrications. This work stresses the importance of developing CP films and reveals their critical role in the evolution of these next-generation devices featuring wearable, deformable, printable, ultrathin, and see-through characteristics.
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http://dx.doi.org/10.1002/advs.201900813DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6774040PMC
October 2019

One-Pot and Postsynthetic Phenol-Thermal Synthesis toward Highly Stable Titanium-Oxo Clusters.

Inorg Chem 2019 Oct 19;58(19):13353-13359. Epub 2019 Sep 19.

State Key Laboratory of Structural Chemistry , Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou , Fujian 350002 , People's Republic of China.

The synthetic approach plays a crucial role for the exploration and optimization of functional materials. As the molecular models of titanium dioxide, polyoxo-titanium clusters have undergone rapid development over past decade. Unfortunately, many of them are unstable, especially in aqueous environments, greatly limiting their applications in catalysis and environmental fields. In this work, we report a novel phenol-thermal approach toward the construction of highly stable polyoxo-titanium clusters. In addition to the traditional one-pot procedure, the phenol-thermal synthesis can also be used as a postsynthetic pathway to modify the alcohol terminated titanium-oxo clusters. During the modification in phenol, Ti-O core structures consisting entirely of 6-coordinated Ti centers can be retained. Nevertheless, isopropanol terminated 5-coordinated Ti centers are not stable and reconstructed to 6-coordinated Ti centers during the phenol-thermal modification to form new Ti-O clusters. Physical attribute studies confirm that the obtained phenolic clusters generally display much better stability and stronger visible light absorption than isopropanol stabilized clusters with identical or similar cores. Therefore, phenol can not only offer a suitable solution environment for the construction of new cluster structures but also provide robust protection for the cluster cores and also an efficient method to enhance their visible light responses.
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http://dx.doi.org/10.1021/acs.inorgchem.9b02238DOI Listing
October 2019

Pyrazole-thermal synthesis: a new approach towards N-rich titanium-oxo clusters with photochromic behaviors.

Dalton Trans 2019 Jun 22;48(23):8049-8052. Epub 2019 May 22.

State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China.

A novel pyrazole-thermal approach has been successfully developed to synthesize titanium-oxo clusters doped with abundant nitrogen. The coordinated ligands of the obtained clusters have significant effects on their photochromic behaviors.
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http://dx.doi.org/10.1039/c9dt01628gDOI Listing
June 2019

Isomerism in Titanium-Oxo Clusters: Molecular Anatase Model with Atomic Structure and Improved Photocatalytic Activity.

Angew Chem Int Ed Engl 2019 Jan 20;58(5):1320-1323. Epub 2018 Dec 20.

State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, 350002, Fuzhou, P. R. China.

Phase isomerism is a common and important phenomenon in inorganic materials, but the molecular isomerism of their nanocluster models is still rare. In this work, we report the first pair of isomeric titanium-oxo clusters. Through combining pentagonal {Ti(Ti )} building units in corner-sharing or edge-sharing forms, the two obtained Ti -oxo clusters take vertical and horizontal core configurations, respectively, which are both functionalized by the same organic ligands. More interestingly, the vertical type Ti -oxo core contains an identical {Ti O } moiety as anatase, making it the first molecular model of anatase TiO . As a result, the vertical type cluster exhibits better photocatalytic H evolution activity, higher photocurrent response and faster charge transfer to external acceptors than its horizontal isomer. Thus, this work provides a cluster isomer method to understand the structure-property relationship of import titanium oxide materials.
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http://dx.doi.org/10.1002/anie.201809961DOI Listing
January 2019

All-Solution-Processed Metal-Oxide-Free Flexible Organic Solar Cells with Over 10% Efficiency.

Adv Mater 2018 Jun 16;30(26):e1800075. Epub 2018 May 16.

Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China.

All-solution-processing at low temperatures is important and desirable for making printed photovoltaic devices and also offers the possibility of a safe and cost-effective fabrication environment for the devices. Herein, an all-solution-processed flexible organic solar cell (OSC) using poly(3,4-ethylenedioxythiophene):poly-(styrenesulfonate) electrodes is reported. The all-solution-processed flexible devices yield the highest power conversion efficiency of 10.12% with high fill factor of over 70%, which is the highest value for metal-oxide-free flexible OSCs reported so far. The enhanced performance is attributed to the newly developed gentle acid treatment at room temperature that enables a high-performance PEDOT:PSS/plastic underlying substrate with a matched work function (≈4.91 eV), and the interface engineering that endows the devices with better interface contacts and improved hole mobility. Furthermore, the flexible devices exhibit an excellent mechanical flexibility, as indicated by a high retention (≈94%) of the initial efficiency after 1000 bending cycles. This work provides a simple route to fabricate high-performance all-solution-processed flexible OSCs, which is important for the development of printing, blading, and roll-to-roll technologies.
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http://dx.doi.org/10.1002/adma.201800075DOI Listing
June 2018

Dicarboxylate Ligands Oriented Assembly of {Ti(μ-O)} Units: From Dimer to Coordination Triangles and Rectangles.

Inorg Chem 2018 May 17;57(9):5642-5647. Epub 2018 Apr 17.

State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter , Chinese Academy of Sciences , Fuzhou , Fujian 350002 , P. R. China.

A series of dicarboxylates bridged titanium-oxo clusters with {Ti(μ-O)} building units have been synthesized through facile one-step solvothermal reactions. It is interesting to find that the geometric characteristics of the obtained supramolecular structures highly depend on the configuration of the applied dicarboxylate ligands. A linear dimeric [TiO]L complex can be constructed using flexible cyclohexanedicarboxylic acid, while the introduction of rigid 2-nitro-1,4-benzenedicarboxylic acid gives rise to a triangular [TiO]L structure. Moreover, unusual [TiO]L rectangles have been achieved with more symmetric 5-nitro-1,3-benzenedicarboxylic acid or terephthalic acid. Furthermore, a photochromic effect is observed on the obtained complexes upon UV-vis light irradiation in the presence of alcohol.
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http://dx.doi.org/10.1021/acs.inorgchem.8b00586DOI Listing
May 2018

A Methodological Study on Tuning the Thermally Activated Delayed Fluorescent Performance by Molecular Constitution in Acridine-Benzophenone Derivatives.

Chem Asian J 2018 May 30;13(9):1187-1191. Epub 2018 Mar 30.

Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, P.R. China.

Thermally activated delayed fluorescent (TADF) emitters are usually designed as donor-acceptor structures with large dihedral angles, which tend to incur low fluorescent efficiency, and therefore, through molecular design various strategies have been proposed to increase the efficiency of emitters; however, few studies have compared these strategies in one TADF system. In this study, a novel TADF molecule, [4-(9,9-diphenylacridin-10-yl)phenyl](phenyl)methanone (BP-DPAC), was designed as a prototype, and two derivatives, BP-Ph-DPAC and DPAC-BP-DPAC, were also prepared to represent two common approaches to enhance TADF performance. Compared with the maximum external quantum efficiency (EQE) of 6.82 % for BP-DPAC, organic light-emitting diodes (OLED) devices based on DPAC-BP-DPAC exhibited enhanced TADF properties with the highest maximum EQE of 18.67 %, owing to an additional diphenylacridine donor, whereas BP-Ph-DPAC showed non-TADF properties and exhibited the lowest EQE of 4.25 %, owing to the insertion of a phenyl ring between donor and acceptor.
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http://dx.doi.org/10.1002/asia.201800173DOI Listing
May 2018

Ligand dependent assembly of trinuclear titanium-oxo units into coordination tetrahedra and capsules.

Dalton Trans 2018 Jan;47(3):663-665

State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China.

In the presence of phosphorous acid and by selecting different bridging ligands, trinuclear Ti(μ-O) units have been assembled into coordination cages with topologies such as {Ti} clusters, {TiCu} tetrahedrons and {Ti} capsules.
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http://dx.doi.org/10.1039/c7dt04204cDOI Listing
January 2018

Angle resolved vibrational properties of anisotropic transition metal trichalcogenide nanosheets.

Nanoscale 2017 Mar;9(12):4175-4182

School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287, USA.

Layered transition metal trichalcogenides (TMTCs) are a new class of anisotropic two-dimensional materials that exhibit quasi-1D behavior. This property stems from their unique highly anisotropic crystal structure where vastly different material properties can be attained from different crystal directions. Here, we employ density functional theory predictions, atomic force microscopy, and angle-resolved Raman spectroscopy to investigate their fundamental vibrational properties which differ significantly from other 2D systems and to establish a method in identifying anisotropy direction of different types of TMTCs. We find that the intensity of certain Raman peaks of TiS, ZrS, and HfS have strong polarization dependence in such a way that intensity is at its maximum when the polarization direction is parallel to the anisotropic b-axis. This allows us to readily identify the Raman peaks that are representative of the vibrations along the b-axis direction. Interestingly, similar angle resolved studies on the novel TiNbS TMTC alloy reveal that determination of anisotropy/crystalline direction is rather difficult possibly due to loss of anisotropy by randomization distribution of quasi-1D MX chains by the presence of defects which are commonly found in 2D alloys and also due to the complex Raman tensor of TMTC alloys. Overall, the experimental and theoretical results establish non-destructive methods used to identify the direction of anisotropy in TMTCs and reveal their vibrational characteristics which are necessary to gain insight into potential applications that utilize direction dependent thermal response, optical polarization, and linear dichroism.
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http://dx.doi.org/10.1039/c7nr00711fDOI Listing
March 2017

Assembling Polyoxo-Titanium Clusters and CdS Nanoparticles to a Porous Matrix for Efficient and Tunable H -Evolution Activities with Visible Light.

Adv Mater 2017 Feb 29;29(5). Epub 2016 Nov 29.

State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, 350002, Fuzhou, China.

Polyoxo-titanium clusters (PTCs) are applied to construct highly efficient ternary PTC/CdS/MIL-101 visible-light-range H -evolution photocatalysts. The application of PTCs not only increases the photocatalytic activities but also provides a molecular tool to tune them.
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http://dx.doi.org/10.1002/adma.201603369DOI Listing
February 2017

Strong dichroic emission in the pseudo one dimensional material ZrS.

Nanoscale 2016 Sep;8(36):16259-16265

School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287, USA.

Zirconium trisulphide (ZrS), a member of the layered transition metal trichalcogenides (TMTCs) family, has been studied by angle-resolved photoluminescence spectroscopy (ARPLS). The synthesized ZrS layers possess a pseudo one-dimensional nature where each layer consists of ZrS chains extending along the b-lattice direction. Our results show that the optical properties of few-layered ZrS are highly anisotropic as evidenced by large PL intensity variation with the polarization direction. Light is efficiently absorbed when the E-field is polarized along the chain (b-axis), but the field is greatly attenuated and absorption is reduced when it is polarized vertical to the 1D-like chains as the wavelength of the exciting light is much longer than the width of each 1D chain. The observed PL variation with polarization is similar to that of conventional 1D materials, i.e., nanowires, and nanotubes, except for the fact that here the 1D chains interact with each other giving rise to a unique linear dichroism response that falls between the 2D (planar) and 1D (chain) limit. These results not only mark the very first demonstration of PL polarization anisotropy in 2D systems, but also provide novel insight into how the interaction between adjacent 1D-like chains and the 2D nature of each layer influences the overall optical anisotropy of pseudo-1D materials. Results are anticipated to have an impact on optical technologies such as polarized detectors, near-field imaging, communication systems, and bio-applications relying on the generation and detection of polarized light.
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http://dx.doi.org/10.1039/c6nr05238jDOI Listing
September 2016

Unusual lattice vibration characteristics in whiskers of the pseudo-one-dimensional titanium trisulfide TiS.

Nat Commun 2016 Sep 22;7:12952. Epub 2016 Sep 22.

School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287, USA.

Transition metal trichalcogenides form a class of layered materials with strong in-plane anisotropy. For example, titanium trisulfide (TiS) whiskers are made out of weakly interacting TiS layers, where each layer is made of weakly interacting quasi-one-dimensional chains extending along the b axis. Here we establish the unusual vibrational properties of TiS both experimentally and theoretically. Unlike other two-dimensional systems, the Raman active peaks of TiS have only out-of-plane vibrational modes, and interestingly some of these vibrations involve unique rigid-chain vibrations and S-S molecular oscillations. High-pressure Raman studies further reveal that the A S-S molecular mode has an unconventional negative pressure dependence, whereas other peaks stiffen as anticipated. Various vibrational modes are doubly degenerate at ambient pressure, but the degeneracy is lifted at high pressures. These results establish the unusual vibrational properties of TiS with strong in-plane anisotropy, and may have relevance to understanding of vibrational properties in other anisotropic two-dimensional material systems.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5036143PMC
http://dx.doi.org/10.1038/ncomms12952DOI Listing
September 2016

Transfer-Printed PEDOT:PSS Electrodes Using Mild Acids for High Conductivity and Improved Stability with Application to Flexible Organic Solar Cells.

ACS Appl Mater Interfaces 2016 Jun 27;8(22):14029-36. Epub 2016 May 27.

Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Faculty of Physics and Electronic Science, Department of Material Science and Engineering, Hubei University , Wuhan 430062, China.

Unlabelled: Highly conductive, flexible, and transparent electrodes (FTEs) of

Pedot: PSS films on plastic substrates have been achieved using strong acid treatments. However, it is rare to realize a performance attenuation of

Pedot: PSS FTEs on plastic substrates and flexible optoelectronic devices because of strong acid residues in the

Pedot: PSS matrix. Herein, we develop a feasible transfer-printing technique using mild acids. Because of a mild and weak property of these acids and less acid residues in

Pedot: PSS matrix, the transferred

Pedot: PSS FTEs exhibited a significant enhancement in stability, conductivity (3500 S cm(-1)), transparency, and mechanical flexibility on plastic substrates. Flexible organic solar cells with the FTEs also showed a remarkable enhancement in power conversion efficiency and stability in the ambient atmosphere. It is expected that the novel transfer-printing technique for making

Pedot: PSS FTEs is also useful in many other types of flexible optoelectronic devices.
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http://dx.doi.org/10.1021/acsami.6b01389DOI Listing
June 2016

Decreasing the Viscosity in CO2 Capture by Amino-Functionalized Ionic Liquids through the Formation of Intramolecular Hydrogen Bond.

J Phys Chem B 2016 Mar 8;120(10):2807-13. Epub 2016 Mar 8.

Department of Chemistry, ZJU-NHU United R&D Center, and ‡Key Laboratory of Biomass Chemical Engineering of Ministry of Education, Zhejiang University , Hangzhou 310027, China.

A strategy for decreasing the viscosity variation in the process of CO2 capture by amino-functionalized ionic liquids (ILs) through the formation of intramolecular hydrogen bond was reported. Different with the dramatic increase in viscosity during CO2 uptake by traditional amino-functionalized ILs, slight increase or even decrease in viscosity was achieved through introducing a N or O atom as hydrogen acceptor into amino-functionalized anion, which could stabilize the active hydrogen of produced carbamic acid. Quantum chemical calculations and spectroscopic investigations demonstrated that the formation of intramolecular hydrogen bond between introduced hydrogen acceptor and carbamic acid was the key to avoid the dramatic increase in viscosity during the capture of CO2 by these amino-functionalized ILs.
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http://dx.doi.org/10.1021/acs.jpcb.5b10553DOI Listing
March 2016

Bendable ITO-free Organic Solar Cells with Highly Conductive and Flexible PEDOT:PSS Electrodes on Plastic Substrates.

ACS Appl Mater Interfaces 2015 Aug 23;7(30):16287-95. Epub 2015 Jul 23.

†Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Faculty of Physics and Electronic Science, Hubei University, Wuhan 430062, People's Republic of China.

Unlabelled: Flexible and transparent electrodes have great potential for photon transmission and charge-carrier collection for next generation electronics compared to rigid electronics with indium tin oxide (ITO)-coated glass substrates. This study describes a comprehensive study of the electrical, morphological, optical, structural, and mechanical properties of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (

Pedot: PSS) films treated by methanol and methanesulfonic acid (MSA), which are coated on hydrophobic flexible plastic substrates. Such a film coated on hydrophobic plastic substrates exhibits a high conductivity up to 3560 S cm(-1) and a good mechanical flexibility. Moreover, the use of the films to fabricate bendable ITO-free organic solar cells (OSCs) integrated on plastic substrates was presented. The bendable devices based on P3HT:PCBM not only exhibit a high power conversion efficiency (PCE) up to 3.92%, which is comparable to 4.30% of the rigid devices with ITO-coated glass substrates, but also keep about 80% in PCE of the initial value after 100 time bending with a bending radius of 14 mm in the ambient atmosphere. This work provides a novel route to dramatically improve the conductivity of

Pedot: PSS electrodes, as well as the mechanical flexibility of highly efficient organic electronics with the flexible electrodes.
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http://dx.doi.org/10.1021/acsami.5b02830DOI Listing
August 2015

Enhanced efficiency of inverted polymer solar cells by using solution-processed TiOx/CsOx cathode buffer layer.

Nanoscale Res Lett 2015 31;10:29. Epub 2015 Jan 31.

School of Physics and Electromechnical Engineering, Zhoukou Normal University, Zhoukou, 466001 People's Republic of China.

In this work, a double-buffer film of TiOx coated with CsOx (TiOx/CsOx) was solution prepared to be applied in poly(3-hexylthiophene):indene-C60 bisadduct (P3HT:ICBA) and P3HT:[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) inverted polymer solar cells (PSCs). Compared with TiOx films and CsOx films, the TiOx/CsOx double-buffer film exhibited a favorable energy-level alignment among TiOx, CsOx, and the electron acceptor of PCBM or ICBA a better surface morphology; and an enhanced wetting and adhesion property with a contact angle of 21.0°, leading to a higher electron mobility of 5.52 × 10(-3) cm(2) V(-1)·s(-1). Moreover, the P3HT:ICBA and P3HT:PCBM photovoltaic devices with the double-buffer film showed the best power conversion efficiency up to 5.65% and 3.76%, respectively. Our results not only present that the double-buffer film is superior than the single film of TiOx and CsOx, but also imply that the solution-processed film has a potential to be generally used in roll-to-roll processed organic photovoltaic devices.
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http://dx.doi.org/10.1186/s11671-015-0754-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4385094PMC
April 2015

Controllable synthesis of flake-like Al-doped ZnO nanostructures and its application in inverted organic solar cells.

Nanoscale Res Lett 2011 Oct 4;6:546. Epub 2011 Oct 4.

Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Department of Electronic Science and Technology, School of Physics and Technology, Wuhan University, Wuhan, 430072, People's Republic of China.

Flake-like Al-doped ZnO (AZO) nanostructures including dense AZO nanorods were obtained via a low-temperature (100°C) hydrothermal process. By doping and varying Al concentrations, the electrical conductivity (σ) and morphology of the AZO nanostructures can be readily controlled. The effect of σ and morphology of the AZO nanostructures on the performance of the inverted organic solar cells (IOSCs) was studied. It presents that the optimized power conversion efficiency of the AZO-based IOSCs is improved by approximately 58.7% compared with that of un-doped ZnO-based IOSCs. This is attributed to that the flake-like AZO nanostructures of high σ and tunable morphology not only provide a high-conduction pathway to facilitate electron transport but also lead to a large interfacial area for exciton dissociation and charge collection by electrodes.
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http://dx.doi.org/10.1186/1556-276X-6-546DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3212084PMC
October 2011

A D-A copolymer of dithienosilole and a new acceptor unit of naphtho[2,3-c]thiophene-4,9-dione for efficient polymer solar cells.

Chem Commun (Camb) 2011 Oct 14;47(40):11345-7. Epub 2011 Sep 14.

Beijing National Laboratory for Molecular Sciences, Institution of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.

A strong electron-withdrawing unit, naphtho[2,3-c]thiophene-4,9-dione, was copolymerized with dithienosilole to get a D-A copolymer, PDTSNTDO, with a narrow bandgap and lower-lying HOMO level. The PCE of the PDTSNTDO-based device reached 5.21%, with a high open circuit voltage of 0.88 V.
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http://dx.doi.org/10.1039/c1cc14132eDOI Listing
October 2011
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