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Fabrication of peanut-like TiO2 microarchitecture with enhanced surface light trapping and high specific surface area for high-efficiency dye sensitized solar cells
摘要： The quality of TiO2 photoelectrode is critical to fabricate high-performance dye-sensitized solar cells (DSSCs), but constructing TiO2 microstructure with high exposure reactive facets and high specific surface area is still a challenge. Herein, we present a facile route for creating a novel peanut-like (PN) anatase TiO2 microstructure with high exposed (001) facet, enhanced light trapping and large specific surface area using a one-pot hydrothermal method without fluorion assistance. With the introduction of diethylenetriamine as shape controlling agent and two-phase interface by etherification reaction of isopropyl alcohol, anatase PN TiO2 microarchitecture consisted with ultrathin nanosheets can be successfully fabricated. The obtained PN TiO2 combines the advantages of high exposed reactive (001) facets and large specific surface area (180.8 m2/g). The PN TiO2 based DSSC exhibits an outstanding photovoltaic conversion efficiency up to 9.14%, which can attribute to larger dye loading, superior light scattering capability, higher electron collection efficiency, narrower bandgap as well as efficient electron injection, together with improved electron transport and reduced charge recombination due to the unique peanut-like microstructure. Our work demonstrates the potential of PN TiO2 for improving the performance of energy storage devices.
关键词： Dye sensitized solar cell,(001) facet,Titanium dioxide,Improved electron transport,Peanut-like structure
更新于2025-11-14 17:04:02
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A molecular-based design of RGO/TiO2-PAM composite flocculant with photocatalytic self-degrading characteristics and the application of the oil sand tailings flocculant
摘要： Polymer flocculation technology has a very broad application in the flocculation industry of oil sand tailings at present. Nevertheless, the most commonly used commercial polyacrylamide flocculant has problems of low flocculation efficiency and secondary pollution. In this paper, we proposed an organic-inorganic composite flocculant with self-degrading properties for the flocculation treatment of oil sand tailings, which was prepared by photocatalytic surface initiation technique. Further, the functional groups of the materials before and after polymerization composites were characterized by infrared spectrum to explore the polymerization mechanism, the structure was observed by transmission electron microscope, and the molecular weight of polyacrylamide was measured by gel permeation chromatography. Then, the flocculation performance was characterized by the flocculation experiment (tested with simulated oil sand tailings). Subsequently, the flocculation mechanism was explored by testing the zeta potential of the organic-inorganic composites and analyzing images of sediment observed by transmission electron microscope and atomic force microscope. Finally, the test of self-degradation performance was carried out under illumination. Based on the above experiments, the following conclusions were obtained. First, the structural characterization results indicate the polymerization mechanism is that under the condition of light, the surface of the inorganic photocatalyst generates free radicals to initiate the radical polymerization of the monomers, so that the monomers successfully grow on the surface of the inorganic particles into comb structure. And then, the flocculation experiment shows that reduced graphene oxide/titanium dioxide-polyacrylamide(2:40) has the best flocculation effect, of which the supernatant transmittance is 21.4 higher and the sedimentation ratio is 8.9% higher than those of the commercial polyacrylamide. The reason for its excellent flocculation performance is that the zeta potential of the organic-inorganic composite increases, reducing repulsion of particles and flocculant molecules, simultaneously, the formed comb structure is beneficial to the expansion of the polymer chain and increases the contact area, thereby improving the flocculation effect. Ultimately, the degradation results indicates that the new organic-inorganic composite had good degradation effect, with the degradation rate up to 75.9% within 4 hours. Therefore, this work has made great contributions to solving the oil sand tailings pollution field.
关键词： Flocculant,Oil sand tailings,Photocatalytic Self-degrading,Organic-inorganic composite,Comb structure
更新于2025-11-14 17:03:37
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Photoluminescent behaviour of Ce3+ ions in mixed fluoride structures
摘要： Investigations were done to modify the photoluminescence (PL) spectra of a cerium (Ce3+) doped strontium fluoride (SrF2:Ce3+) phosphor for better sensitization for solar cell application. For optimum sensitization it is needed that Ce3+ emission overlaps with Lanthanide (Ln3+) ions’ excitation energy ranges. SrF2:Ce3+ emission, however, does not overlap well with different 4f-4f Ln3+ ions’ excitation ranges. The PL behavior of Ce3+ in Sr1-xMxF2:Ce3+ (where M = Ca, Ba, Mg, La) was therefore investigated. Noticeable changes were observed in the shape of the excitation and emission spectra of Ce3+. The Sr0.49Ba0.50Ce0.01F2 phosphor produced a significant red shift with a broad emission band. The excitation spectrum of this sample was blue shifted if compared to the singly doped sample.
关键词： fluoride structure,XPS,luminescence,Ce3+
更新于2025-11-14 15:28:36
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Syntheses, crystal structures, and photocatalytic properties of two zinc(II) coordination polymers based on dicarboxylates and flexible bis(benzimidazole) ligands
摘要： Two new ternary zinc(II) coordination polymers (CPs), catena-(μ2-phthalato)-(μ2-1,1'-hexane-1,6-diylbis(2-methyl-1H-benzimidazole))-zinc (CP 1) and catena-(μ2-phenylene-1,4-diacetato)-(μ2-1,1'-hexane-1,6-diylbis(1H-benzimidazole))-zinc (CP 2) were synthesized via hydrothermal process. CP 1 and CP 2 are named as [Zn(L1)(PA)]n and [Zn(L2)(PDA)]n (L1 = 1,1'-hexane-1,6-diylbis(2-methyl-1H-benzimidazole), L2 = 1,1'-hexane-1,6-diylbis(1H-benzimidazole), H2PA = phthalic acid, H2PDA = 1,4-phenylenediacetic acid)), respectively. Both CPs were characterized by elemental analysis, infrared spectroscopy, single crystal X-ray diffraction analysis. CP 1 possesses a 4-connected 66-dia network, CP 2 displays a 2D hcb layer with point symbol {63}. Luminescence, UV-vis diffuse reflection spectra, and photocatalytic properties of two CPs for the degradation of the methylene blue (MB) dye were investigated. The mechanism of photocatalytic degradation of MB was also suggested.
关键词： Zinc(II),Crystal structure,Bis(benzimidazole),Photocatalytic property,Coordination polymer
更新于2025-11-14 15:28:36
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The effect of second phase La0.67TiO2.87 on the phase structure and impedance spectroscopy of La2Ti2(1 + x)O7 piezoelectric ceramics
摘要： The Ti excess La2Ti2 (1 + x) O7 (x = 0, 0.005, 0.01, 0.02, 0.05, 0.1) piezoelectric ceramics have been prepared by sol-gel technology and solid state synthesis method. Through refinement analysis, the phase structure of the ceramics varies with Ti content. Most monoclinic phase (~ 93 %) and a handful of orthogonal phase (~ 7 %) coexist in La2Ti2 (1 + 0) O7 ceramics. Pure monoclinic phase La2Ti2O7 with space group P21 appears in La2Ti2 (1 + 0.005) O7 and La2Ti2 (1 + 0.01) O7 ceramics. Monoclinic phase La2Ti2 O7 and a certain proportion of tetragonal phase La0.67TiO2.87 coexist in La2Ti2 (1 + 0.02) O7, La2Ti2 (1 + 0.05) O7 and Ti2 (1 + 0.1) O7 ceramics. With the excess of Ti content, the monoclinic phase ratio and distortion angles in a-b projection plane of the ceramics increase first and then decrease, which is consistent with the variation tendency of piezoelectric constant d33. The excellent piezoelectric constant for Ti2 (1 + 0.01) O7 ceramics is 2.8 pC/N. Impedance analysis shows that the conductive mechanisms of all samples include both grain and grain boundary conductivity at temperature range T ≥ 500 ℃. The formation of tetragonal phase La0.67TiO2.87 derives from Ti excess in pure monoclinic phase La2Ti2O7. The existence of tetragonal phase La0.67TiO2.87 can obviously increase the capacitance of ceramics at x ≥ 0.05. All prepared piezoelectric La2Ti2 (1 + x) O7 ceramics have highly frequency stability and are candidates for ultrahigh temperature piezoelectric application.
关键词： La2Ti2(1 + x)O7 ceramics,phase structure,impedance spectroscopy
更新于2025-11-14 15:27:09
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High Efficiency Non‐Doped White Organic Light Emitting Diodes Based on a Bilayer Interface‐Exciplex Structure
摘要： High efficiency non-doped blue and white organic light emitting diodes (OLEDs) are realized by using a bilayer interface-exciplex (i-Exc) structure. Since the neutral exciplex are formed at the interface, the interface charge accumulation is reduced, thereby suppressing exciton quenching in the device. With the i-Exc structure, a maximum external quantum efficiency (EQE) of 23.1% is achieved in the non-doped blue phosphorescent OLED. Moreover, the white emission can be obtained by inserting an ultrathin orange-red phosphorescent emitter into the blue devices. The charge trapping in the orange-red emitter can be suppressed by adjusting the position of the ultrathin orange-red emitting layer in the device, contributing to superior spectral stability. The WOLED achieves an EQE of 20.0% and exhibits a stable warm white emission. The Commission Internationale de l’Eclairage (CIE) coordinates of WOLED are (0.41, 0.40) at 5 V and slightly change to (0.40, 0.41) at 9 V.
关键词： interface-exciplex,PHOLED,WOLED,bilayer structure,ultrathin non-doped emitting layers
更新于2025-11-14 15:26:12
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A new disordered langbeinite-type compound, K <sub/>2</sub> Tb <sub/>1.5</sub> Ta <sub/>0.5</sub> P <sub/>3</sub> O <sub/>12</sub> , and Eu <sup>3+</sup> -doped multicolour light-emitting properties
摘要： For the first time, a new langbeinite-type phosphate, namely potassium terbium tantalum tris(phosphate), K2Tb1.5Ta0.5(PO4)3, has been prepared successfully using a high-temperature flux method and has been structurally characterized by single-crystal X-ray diffraction. The results show that its structure can be described as a three-dimensional open framework of [Tb1.5Ta0.5(PO4)3] interconnected by K+ ions. The TbIII and TaV cations in the structure are disordered and occupy the same crystallographic sites. The IR spectrum, the UV–Vis spectrum, the morphology and the Eu3+-activated photoluminescence spectroscopic properties were studied. A series of Eu3+-doped phosphors, i.e. K2Tb1.5–xTa0.5(PO4)3:xEu3+ (x = 0.01, 0.03, 0.05, 0.07, 0.10), were prepared via a solid-state reaction and the photoluminescence properties were studied. The results show that under near-UV excitation, the luminescence colour can be tuned from green through yellow to red by simply adjusting the Eu3+ concentration from 0 to 0.1, because of the efficient Tb3+→Eu3+ energy-transfer mechanism.
关键词： photoluminescence,Langbeinite-type phosphate,crystal structure,energy-transfer mechanism,multicolour light
更新于2025-11-14 15:23:50
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Determination of the Thin-Film Structure of Zwitterion-Doped Poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate): A Neutron Reflectivity Study
摘要： Doping poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is known to improve its conductivity, however little is known about the thin film structure of PEDOT:PSS when doped with an asymmetrically charged dopant. In this study, PEDOT:PSS was doped with different concentrations of the zwitterion 3-(N,N Dimethylmyristylammonio)propanesulfonate (DYMAP), and its effect on the bulk structure of the films characterized by neutron reflectivity. The results show that at low doping concentration, the film separates into a quasi bi-layer structure with lower roughness (10%), increased thickness (18%), and lower electrical conductivity compared to the un-doped sample. However when the doping concentration increases the film forms into a homogeneous layer and experiences an enhanced conductivity by more than an order of magnitude, a 20% smoother surface, and a 60% thickness increase relative to the pristine sample. Atomic force microscopy and profilometry measurements confirmed these findings, and AFM height and phase images showed the gradually increasing presence of DYMAP on the film surface as a function of the concentration. Neutron reflectivity also showed that the quasi bi-layer structure of the lowest concentration doped PEDOT:PSS is separated by a graded rather than a well defined interface. Our findings provide an understanding of the layer structure modification for doped PEDOT:PSS films that should be prove important for device applications.
关键词： neutron reflectivity,hole transporting layer,conductivity,film structure,zwitterion,PEDOT:PSS
更新于2025-11-14 15:19:41
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How to unravel the chemical structure and component localization of individual drug-loaded polymeric nanoparticles by using tapping AFM-IR
摘要： AFM-IR is a photothermal technique that combines AFM and infrared (IR) spectroscopy to unambiguously identify the chemical composition of a sample with tens of nanometer spatial resolution. So far, it has been successfully used in contact mode in a variety of applications. However, the contact mode is unsuitable for soft or loosely adhesive samples such as polymeric nanoparticles (NPs) of less than 200 nm of wide interest for biomedical applications. We describe here the theoretical basis of the innovative tapping AFM-IR mode that can address novel challenges in imaging and chemical mapping. The new method enables gaining information not only on NP morphology and composition, but also reveals drug location and core–shell structures. Whereas up to now the locations of NP components could only be hypothesized, tapping AFM-IR allows accurately visualizing both the location of the NPs’ shells and that of the incorporated drug, pipemidic acid. The preferential accumulation of the drug in the NPs’ top layers was proved, despite its low concentration (<1 wt%). These studies pave the way towards the use of tapping AFM-IR as a powerful tool to control the quality of NP formulations based on individual NP detection and component quantification.
关键词： tapping mode,chemical mapping,core–shell structure,drug localization,polymeric nanoparticles,AFM-IR
更新于2025-11-14 15:18:02
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Structural and spectroscopic studies of bromofullerene
摘要： Structural and spectroscopic studies on fullerene and bromofullerene molecules were investigated. The reaction with liquid bromine was used to prepare bromofullerene and it was characterized by using X-ray diffraction, ultravioletevisible, Fourier transform infrared, Fourier transform Raman, electron paramagnetic resonance, scanning electron microscopy, high resolution transmission electron and energy dispersive X-ray techniques. The XRD pattern of bromofullerene con?rms the attachment of bromine to fullerene. FT-IR and FT-Raman characterization reveal the C-Br vibrations in the brominated fullerene which con?rms the bromination. UVeVis spectral analysis endorses shifting of absorption peak. EPR line width, with g-factor values, indicates the magnetic ion sites in the samples. Scanning electron microscope and high resolution transmission electron microscope signify the changes in surface and particle size of the molecule. The particle size was calculated from Debey-Sherrer's formula and corroborated by TEM images. Energy dispersive X-ray elemental micro analysis con?rms the presence of bromine element in the molecule. The enhanced reactivity by substitution of bromine paves the way for designing the bioactive molecules which will be useful in the ?eld of carbon nano-medicine and targeted drug delivery applications.
关键词： Bromination,HRTEM,Structure properties,Fullerene
更新于2025-11-14 15:16:37