用于非对称超级电容器的S掺杂NiTe电极材料的制备及性能研究

用简单的一步水热法制备了S掺杂的NiTe(NiTe∶S)纳米片。利用X射线衍射(XRD)、能谱仪(EDS)以及场发射扫描电镜(FESEM)等分析技术对材料物相和形貌进行表征。并将制得的NiTe∶S作为超级电容器的电极材料,电化学性能测试结果表明,S∶Te掺杂的比例对材料的电化学性能有较大的影响,当x(S)∶x(Te)=3∶50时,电极材料在5 A/g的电流密度下的比电容达到887.3 F/g,与未掺杂时相比提高了214%。此外,利用所制备NiTe∶S电极(正极)与活性炭电极(AC)(负极)组装成非对称超级电容器。该非对称超级电容器展现出了优异的电化学性能,其能量密度和功率密度能达32.8 Wh/kg和800.5 W/kg。

Application of upconversion luminescence in dye-sensitized solar cells

An upconversion luminescence powder TiO2:(Er3+,Yb3+) is prepared by a hydrothermal method and used to fabricate dye-sensitized solar cell (DSSC).The TiO2:(Er3+,Yb3+) powder undergoes upconversion luminescence,converting infrared light which the dye can not absorb into visible light with wavelengths of 510-700 nm which the dye can absorb,increasing the photocurrent of the DSSC.TiO2:(Er3+,Yb3+) also acts as a p-type dopant,heightening the Fermi level of the oxide film,which increases the photovoltage of the DSSC.The best performance of the DSSC is found when the ratio of TiO2/luminescence powder is 1/3 in the luminescence layer.Under simulated solar irradiation of 100 mW cm-2 (AM 1.5),the DSSC containing TiO2:(Er3+,Yb3+) doping achieves a light-to-electricity energy conversion efficiency of 7.28% compared with 6.41% for the undoped DSSC.

Controllable hydrothermal synthesis of nanocrystal TiO_2 particles and their use in dye-sensitized solar cells

A simple method for the controllable hydrothermal synthesis of nanocrystalline anatase TiO2(nc-TiO2) particles involving the selection of suitable organic alkali peptizing agents is reported.A dye-sensitized solar cell(DSSC) with square-like nc-TiO2 particles with side lengths about 8-13 nm-prepared using tetraethylammonium hydroxide(TEAOH)-in the photoelectrode showed higher photovoltaic performance than two other DSSCs with square-like nc-TiO2 particles with side lengths about 7-10 nm-prepared using tetrabutylammonium hydroxide-or elongated nc-TiO2 particles with lengths about 18-35 nm and width about 10 18 nm-prepared using tetramethylammonium hydroxide(TMAOH)-in the photoelectrodes.When a scattering layer prepared from sub-micron size spheres or cone-like nc-TiO2 particles-synthesized using a higher concentration of TMAOH-was added on top of the photoelectrode fabricated from nc-TiO2 synthesized with TEAOH,the energy conversion efficiency of the DSSC was markedly increased from 6.77% to 8.18%.

Efficiency improvement of flexible dye-sensitized solar cells by introducing mesoporous TiO_2 microsphere

Mesoporous TiO2microsphere(MTM)was synthesized via a simple solution route and then mixed with commercial TiO2(P25)to form highly homogeneous and stable TiO2colloid by simple hydrothermal treatment.The TiO2colloid was coated onto the plastic conductive substrate to prepare mesoporous TiO2film for flexible dye-sensitized solar cells(DSSCs)by low-temperature heat treatment.The influence of MTM content on the physicochemical properties of the flexible TiO2film was characterized by scanning electron microscope,transmission electron microscopy,X-ray diffraction,energy-dispersive X-ray spectrometer,N2adsorption-desorption isotherms,UV–vis absorption and diffuse reflectance spectra.It is revealed that with increasing the MTM content,the dye-loading capability of TiO2film and light-harvesting efficiency of flexible DSSCs are improved due to MTM having high surface area and acting as a light scattering center,respectively,resulting in the enhancement of photocurrent of flexible DSSCs.However,more and larger cracks having negative effect on the performances of flexible DSSCs are formed simultaneously.Under the optimal condition with MTM content of 20%,a flexible DSSC with overall light-to-electric energy conversion efficiency of 2.74%is achieved under a simulated solar light irradiation of 100 mW cm 2(AM 1.5),with 26%improvement in comparison with DSSCs based on P25 alone.

Application of a novel redox-active electrolyte in MnO_2-based supercapacitors

This paper reports a novel strategy for preparing redox-active electrolyte through introducing a redox-mediator(p-phenylenediamine,PPD) into KOH electrolyte for the application of ball-milled MnO 2-based supercapacitors.The morphology and compositions of ball-milled MnO 2 were characterized using scanning electron microscopy(SEM) and X-ray diffraction(XRD).The electrochemical properties of the supercapacitor were evaluated by cyclic voltammetry(CV),galvanostatic charge-discharge(GCD),and electrochemical impedance spectroscopy(EIS) techniques.The introduction of p-phenylenediamine significantly improves the performance of the supercapacitor.The electrode specific capacitance of the supercapacitor is 325.24 F g-1,increased by 6.25 folds compared with that of the unmodified system(44.87 F g-1) at the same current density,and the energy density has nearly a 10-fold increase,reaching 10.12 Wh Kg-1.In addition,the supercapacitor exhibits good cycle-life stability.

Gelation of a liquid electrolyte with aniline for use in a quasi-solid-state dye-sensitized solar cell

A new kind of gel electrolyte containing only organic solvents and an iodide salt-namely 3-methoxypropionitrile(MPN),aniline and AlI 3 -has been prepared.Gel formation results from the Lewis acid-base interaction between the Lewis acid ionic conductor AlI 3 and the Lewis base organic solvent aniline and no additional gelling agent is required.The AlI 3-aniline complex acts both as an ionic conductor and as a gelling agent.The differences between the peaks characteristic of the-NH 2 group and aromatic ring in the FTIR spectra of free aniline and the AlI 3-aniline hybrid confirm the formation of the AlI 3-aniline complex.The photovoltaic performance and long-term stability of dye-sensitized solar cells can be greatly enhanced by the addition of aniline to the AlI 3-MPN liquid electrolyte.

A dye-sensitized solar cell based on PEDOT:PSS counter electrode

A counter electrode for dye-sensitized solar cell (DSSC) was prepared by coating poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) with high transparency and adhesion on a conducting FTO glass at low temperature. The surface morphology, conductivity, sheet resistance, redox properties and photoelectric properties of the PEDOT:PSS/carbon electrodes were observed using scanning electron microscopy, a four-probe tester and a CHI660D electrochemical measurement system. The experimental results showed that DSSCs had the best photoelectric properties for PEDOT:PSS/carbon counter electrodes annealed at 80°C under vacuum conditions. The overall energy conversion efficiency of the DSSC with PEDOT:PSS/carbon counter electrode and barrier layer reached 7.61% under irradiation from a simulated solar light with intensity of 100 mW/cm2 (AM 1.5). The excellent photoelectric properties, simple preparation procedure and low cost allow the PEDOT:PSS/carbon electrode to be a credible alternative electrode for use in DSSCs.

TiCl_4 assisted formation of nano-TiO_2 secondary structure in photoactive electrodes for high efficiency dye-sensitized solar cells

A new kind of photoactive electrodes with nanocrystalline TiO2(nano-TiO2)secondary structure is successfully prepared via a simple method of adding a small amount of TiCl4 2-propanol solution in conventional nano-TiO2 paste to form micro-sized nano-TiO2 aggregates.The benefits of this special structure include improved optical absorption,increased light scattering ability,and enhanced electron transport and collection efficiency.Dye-sensitized solar cells(DSCs)based on these photoactive electrodes show improved performance.The power conversion efficiency of the cells can be increased from 5.03%to 7.30%by substituting 6μm conventional nano-TiO2 thin film with the same thickness of as-prepared nano-TiO2 aggregates film in the photoactive electrodes.A higher power conversion efficiency of the cells can be obtained by further increasing the thickness of the nano-TiO2 aggregates film.

Quantum dot-sensitized solar cells employing Pt/C_(60) counter electrode provide an efficiency exceeding 2%

A microporous platinum/fullerenes (Pt/C 60) counter electrode was prepared by using a facile rapid thermal decomposition method,and the quantum-dot sensitized solar cell (QDSSC) of Pt/C 60-TiO 2-CdS-ZnS and Pt/C 60-TiO 2-CdTe-ZnS was fabrication.The technique forms a good contact between QDs and TiO 2 films.The photovoltaic performances of the as-prepared cells were investigated.The QDSSCs with Pt/C 60 counter electrode show high power conversion efficiency of 1.90% and 2.06%,respectively (under irradiation of a simulated solar light with an intensity of 100 mW cm 2),which is comparable to the one fabricated using conventional Pt electrode.