| 1. |
- Dong, Suzi, et al.
(författare)
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An effective surface-enhanced Raman scattering template based on a Ag nanocluster–ZnO nanowire array
- 2009
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Ingår i: Nanotechnology. - : Institute of Physics Publishing (IOPP). - 0957-4484 .- 1361-6528. ; 20:17, s. 175705-
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Tidskriftsartikel (refereegranskat)abstract
- An effective surface-enhanced Raman scattering (SERS) template based on a 3D hybrid Ag nanocluster (NC)-decorated ZnO nanowire array was fabricated through a simple process of depositing Ag NCs on ZnO nanowire arrays. The effects of particle size and excitation energy on the Raman scattering in these hybrid systems have been investigated using rhodamine 6G as a standard analyte. The results indicate that the hybrid nanosystem with 150 nm Ag NCs produces a larger SERS enhancement factor of 3.2 × 108, which is much higher than that of 10 nm Ag NCs (6.0 × 106) under 532 nm excitation energy. The hybrid nanowire arrays were further applied to obtain SERS spectra of the two-photon absorption (TPA) chromophore T7. Finite-difference time-domain simulations reveal the presence of an enhanced field associated with inter-wire plasmon coupling of the 150 nm Ag NCs on adjacent ZnO nanowires; such a field was absent in the case of the 10 nm Ag NC-coated ZnO nanowire. Such hybrid nanosystems could be used as SERS substrates more effectively than assembled Ag NC film due to the enhanced light-scattering local field and the inter-wire plasmon-enhanced electromagnetic field.
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| 2. |
- Xie, Zhibin, et al.
(författare)
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Highly efficient dye-sensitized solar cells using phenothiazine derivative organic dyes
- 2010
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Ingår i: Progress in Photovoltaics. - : John Wiley & Sons. - 1062-7995 .- 1099-159X. ; 18:8, s. 573-581
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Tidskriftsartikel (refereegranskat)abstract
- Two novel organic dyes have been synthesized using electron rich phenothiazine as electron donors and oligothiophene vinylene as conjugation spacers. The two dyes (2E)-2-cyano-3-(5-(5-((E)-2-(10-(2-ethylhexyl)-10H-phenothiazin-7-yl)vinyl)thiophen-2-yl)thiophen-2-yl)acrylic acid (PTZ-1) and (2E)-3-(5-(5-(4,5-bis((E)-2-(10-(2-ethylhexyl)-10H-phenothiazin-3-yl)vinyl)thiophen-2-yl)thiophen-2-yl)thiophen-2-yl)-2-cyanoacrylic acid (PTZ-2) were fully characterized and employed in dye-sensitized solar cells (DSCs) to explore the effect of disubstituted donors on photovoltaic (PV) performance. The solar cells sensitized by the PTZ1 dye have a high IPCE plateau of 80% and achieve a short-circuit photocurrent density of 12.98 mA/cm2, an open-circuit voltage of 0.713 V, and a fill factor (ff) of 66.6%, corresponding to a conversion efficiency of 6.17% under AM 1.5 100 mW/cm2 illumination. The different performance of the solar cells based on the two dyes can be understood from the studies of the electron kinetics by electrochemical impedance spectroscopy (EIS). These investigations reveal that disubstituted donors in the organic sensitizers of three or more conjugation units deteriorate the PV performance due to enhanced recombination.
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| 3. |
- Xu, Hai-Sen, et al.
(författare)
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Divergent Chemistry Paths for 3D and 1D Metallo-Covalent Organic Frameworks (COFs)
- 2020
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Ingår i: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 59:28, s. 11527-11532
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Tidskriftsartikel (refereegranskat)abstract
- The marriage of dynamic covalent chemistry (DCC) and coordination chemistry is a powerful tool for assembling complex architectures from simple building units. Recently, the synthesis of woven covalent organic frameworks (COFs) with topologically fascinating structures has been achieved using this approach. However, the scope is highly limited and there is a need to discover new pathways that can assemble covalently linked organic threads into crystalline frameworks. Herein, we have identified branching pathways leading to the assembly of three-dimensional (3D) woven COFs or one-dimensional (1D) metallo-COFs (mCOFs), where the mechanism is underpinned by the absence or presence of ligand exchange.
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| 4. |
- Xu, Hai-Sen, et al.
(författare)
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Single crystal of a one-dimensional metallo-covalent organic framework
- 2020
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Although polymers have been studied for well over a century, there are few examples of covalently linked polymer crystals synthesised directly from solution. One-dimensional (1D) covalent polymers that are packed into a framework structure can be viewed as a 1D covalent organic framework (COF), but making a single crystal of this has been elusive. Herein, by combining labile metal coordination and dynamic covalent chemistry, we discover a strategy to synthesise single-crystal metallo-COFs under solvothermal conditions. The single-crystal structure is rigorously solved using single-crystal electron diffraction technique. The non-centrosymmetric metallo-COF allows second harmonic generation. Due to the presence of syntactic pendant amine groups along the polymer chains, the metallopolymer crystal can be further cross-linked into a crystalline woven network. Although polymers have been studied for well over a century, there are few examples of covalently linked polymer crystals synthesized directly from solution. Here, the authors demonstrate a strategy to synthesize single crystalline 1D metallo-covalent organic frameworks by combining dynamic covalent chemistry and metal-ligand coordination.
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| 5. |
- Zhang, Xuanjun, et al.
(författare)
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Aggregation dependent S1 and S2 dual emissions of thiophene-acrylonitrile-carbazole oligomer
- 2008
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Ingår i: Crystal Growth & Design. - : American Chemical Society (ACS). - 1528-7483 .- 1528-7505. ; 8:7, s. 2543-2546
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Tidskriftsartikel (refereegranskat)abstract
- Dual emissions from S1 (blue region) and S2 (UV region) states of a chromophore with donor−acceptor structure were observed at room temperature. The photophysical properties of the chromophore depend critically on the packing of the molecules. The molecule exhibits weak S1 emission and strong S2 emission; however, when it undergoes solid aggregation, the S1 emission is enhanced while the S2 emission is quenched. The H-packing (face-to-face packing) of the molecules is revealed as the key factor for this interesting aggregation-dependent dual emission.
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| 6. |
- Zhang, Xuanjun, et al.
(författare)
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Coordination-Assisted Assembly of 1-D Nanostructured Light-Harvesting Anntea
- 2009
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 131:21, s. 7210-7211
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Tidskriftsartikel (refereegranskat)abstract
- An efficient light-harvesting antenna was achieved via self-assembly of two distinct chromophores into nanoscale supramolecular coordination polymers (NSCPs). Efficient fluorescence resonance energy transfer is favorable in the self-assembled 1-D nanostructure as a result of fast and efficient exciton migration in the ordered architecture.
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| 7. |
- Zhang, Xuanjun, et al.
(författare)
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One- and Two-photon Fluorescent Probe for Cysteine and Homocysteine with Large Emission Shift
- 2009
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Ingår i: Organic Letters. - : American Chemical Society (ACS). - 1523-7060 .- 1523-7052. ; 11:6, s. 1257-1260
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Tidskriftsartikel (refereegranskat)abstract
- A novel dendritic chromophore with efficient intramolecular charge transfer (ICT) and strong two-photon absorption (TPA) was designed as a turn-on fluorescent probe for cysteine (Cys) and homocysteine (Hcy). The probe exhibited greatly enhanced fluorescence intensity as well as a very large emission peak shift (165 nm) upon addition of Cys/Hcy due to ICT switch off. The sensing process was also monitored by two-photon excited fluorescence (TPEF).
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