染料敏化太阳能电池二氧化锡光阳极表面原子层沉积氧化铝研究

染料敏化薄膜太阳能电池作为一种新型的太阳能电池吸引了世界范围内的研究。采用二氧化锡代替传统的二氧化钛作为染料敏化太阳能电池的光阳极,使用含有I-/I-3氧化还原电解对的液态电解质。同时,通过原子层沉积(ALD)法,在150℃下使用三甲基铝(TMA)和水作为前驱体和氧化剂沉积氧化铝。并研究了ALD超薄氧化铝包覆二氧化锡颗粒对染料敏化太阳能电池光电转换效率的影响。椭圆偏振仪(SE)分析结果表明ALD每周期沉积速率约为1.2。X射线衍射(XRD)和场发射扫描电镜(FESEM)的结果表明,超薄氧化铝包覆没有影响多孔二氧化锡纳米晶薄膜的晶体结构和表面形貌。紫外-可见光谱(UV-Vis)研究发现随着氧化铝的沉积周期数增加,染料敏化电池光阳极吸附染料的能力增加。最后,对ALD氧化铝对染料敏化太阳能电池性能的影响机理进行了探讨。     

Field-induced formation and manipulation of a microscale liquid ball on an outside wall of the pulled pipette

We report a phenomenological observation of electric-field-induced formation and manipulation of liquid ball on an outer wall of the pulled pipette by using the quartz tuning fork-based atomic force microscope (QTF-AFM). The dye molecule solution with excitation wavelength of 488 nm and detection efficiency of 95% is used to investigate the movement characteristics of liquid droplets when the electric field is applied. The ejected liquid solution forms a microscale liquid droplet at the apex of the pipette by the application of electric field, containing dye molecules, which climbs up along the negatively charged outer surface of the pipette due to the electro-osmosis effect. With positive or negative bias voltages, we manipulate a liquid ball to slide upward or downward, respectively. This field-induced transport of a liquid droplet may be useful to nano-biotechnology or droplet-based microfluidic technology, for example, noncontact delivery and manipulation of liquid solution in the form of separated droplets.     

Photovoltaic and impedance properties of dye-sensitized solar cell based on nature dye from beetroot

The present study involves fabrication and photovoltaic characterization including impedance properties of dye-sensitized solar cells based on natural dye from beetroot. The electrode of the cell was prepared with commercial Fluorine-doped Tin Oxide glass with 100 μm layer of nanostructured TiO₂ whereas, the counter electrode consisted of platinum-coated glass. Fresh juice was extracted from beetroot to use as dye. The dye exhibited high absorption in visible range. Photovoltaic measurements of the solar cell gave a short circuit current density (Jsc) of 130 μA/cm² and an open-circuit voltage (VOC) of 0.38 V under AM 1.5 illumination intensity. The VOC and Jsc showed linear behavior at higher values of illumination intensities. The conductance-voltage, the capacitance-voltage and the series resistance voltage characteristics of the dye solar cell was measured at frequency range from 5 kHz to 5 MHz to study performance of the dye-sensitized solar cells with natural dyes.     

Electroconvection characterization of guest-host nematic liquid crystals for dynamic scattering mode applications

ABSTRACT

The threshold voltage for electro-hydrodynamic convection (EHC) in nematic liquid crystals in the low-frequency convective regime is examined. The addition of dopant species is known to strongly effect the frequency response of this regime. In this work, we investigate the effect of adding optically anisotropic species on the low-frequency threshold, and, demonstrate that certain dichroic dyes have a marked effect. We have measured electrical transport properties of suitably doped liquid crystal mixtures in order to make a comparison with theoretical predictions based upon linear stability considerations. Our results show satisfactory agreement with these predictions. Our findings indicate future directions for new applications of dynamic scattering mode technologies with more accessible operating parameters previously known.     

Geometry,Electronic Structure,and Related Properties of Dye Sensitizer： 3,4-bis[1- （carboxymethyl）-3-indolyl]- 1 H-pyrrole-2,5-dione

The geometry, electronic structure, polarizability and hyperpolarizability of dye sensitizer 3,4-bis[1-（carboxymethyl）-3-indolyl]-1H-pyrrole-2,5-dione （BIMCOOH） were studied using density functional theory （DFT） with hybrid functional B3LYP, and the electronic absorption spectra were investigated using semi-empirical quantum chemical method ZINDO-1 and time-dependent DFT （TDDFT）. The results of natural bond orbital suggest that the natural charges of the dione, indole, and acetic groups are about 0.15e, -0.29e, and 0.44e, respectively. The calculated isotropic polarizability, polarizability anisotropy invariant and hyperpolarizability are 305.4, 188.3, and 1155.4 a.u., respectively. The electronic absorption spectral features in visible and near-UV region were assigned to the π→π^＊ transition due to the qualitative agreement between the experiment and the TDDFT calculations, and the transitions of the excited states 9-11 related to photoinduced intramolecular charge transfer processes. The analysis of electronic structure and UV-Vis absorption indicates that the indole groups primarily contributed sensitization of photo-to-currency conversion processes, and the interracial electron transfer between semiconductor TiO2 electrode and dye sensitizer BIMCOOH are electron injection processes from excited states of the dyes to the semiconductor conduction band.     

Hydrophobic effect for anionic dye - cationic surfactant interaction in aqueous and mixed solvent

Abstract

The interaction between anionic dyes [Reactive Orange 122 (R.O 122), Reactive Blue 19 (R.B 19), Reactive Violet 5 (R.V 5) and Acid Green 20 (A.G 20)] with cationic surfactant cetyltrimethylammoniun bromide (CTAB) has been investigated by spectrophotometry and conductance technique. The used dyes are characterized by tautomeric behavior which affects the mechanism of the interaction. Various parameters such as dye structure, surfactant composition, solvent composition, temperature and pH of the medium were studied. The spectral data were applied for calculating the binding constant between dye and surfactant (K_b), fraction of micellization (?_mic), and standard free energy change of binding (ΔG°_b) in 0,10,20 and 30 v/v % acetonitile (AN). Conductance technique was constructed to estimate the ion pairing constant (K_a) at different temperatures and v/v % AN. Thermodynamic parameters (ΔG°, ΔH° and ΔS°) for ion pair formation were evaluated. The role of hydrophobic and electrostatic effect on dye-surfactant interaction was discussed.     

A scalable synthesis of 1-amino-5-cyanonaphthalene,a precursor for a nitric oxide probe(NO550) designed via the dye assembly principle

A convenient and scalable synthesis of l-amino-5-cyanonaphthalene was described.     

A novel and simple pathway to synthesis of porous polyurea absorbent and its tests on dye adsorption and desorption

A novel one-step protocol for the preparation of porous polyurea material (PPU) through precipitation polymerization of toluene diisocynate (TDI) is presented. The process is based on step polymerization of one singlemonomer, TDI, with water in water-acetonemixed solvent. PPU is obtained without need for any porogen or additives, and no any chemical modification on the outcome polymer is necessary. The morphology, pore size and size distribution of PPU are characterized by scanning electron microscope and BET nitrogen adsorption. Taking acid fuchsine (AF) and Congo Red as dye examples in wastewaters, their adsorption on, desorption from PPU and the reusability of PPU were tested. Experimental conditions for AF adsorption were optimized with regard to pH, adsorption time, AF concentration and amount of PPU. Results demonstrate that the as-prepared PPU is of high performance in dyes adsorption and recycled use. This work presents therefore a novel and attractive candidate for removal of anionic dyes from wastewaters.     

DYE SENSITIZED TITANIA PHOTOVOLTAIC CELLS ON FLEXIBLE SUBSTRATES—CONCEPT TO COMMERCIALIZATION

ABSTRACT

Methods have been found for sintering titania nanoparticles at low temperature, e.g., <150°C, and for rapid sensitization of the sintered particles. This discovery means that dye-sensitized, titania solar cells can be made on flexible substrates, such as poly(ethylene terephthalate), in a continuous roll-to-roll manufacturing process. The ability to produce solar cells in a continuous fashion should substantially lower the cost of the cells compared to batch processed, on-glass cells. The combined attributes of spectral sensitivity, flexibility, light weight, impact resistance and low cost should find utility a variety of handheld appliances in both indoor and outdoor situations. In its most advanced state of development, this technology would find application in off-grid power generation and thus provide the opportunity of bringing solar generated electricity to rural areas of the world.     

3DOM InVO4-supported chromia with good performance for the visible-light-driven photodegradation of rhodamine B

Three-dimensionally ordered macroporous (3DOM) monoclinic InVO₄ and its supported chromia (yCrO_x/3DOM InVO₄, y denotes as the weight percentage of Cr₂O₃, y = 5, 10, 15, and 20 wt%) photocatalysts were fabricated using the ascorbic acid-assisted polymethyl methacrylate-templating and incipient wetness impregnation methods, respectively. Physicochemical properties of the materials were characterized by means of a number of analytical techniques. Photocatalytic activities of the samples were evaluated for the degradation of rhodamine B (RhB) in the presence of H₂O₂ under visible-light illumination. Compared to 3DOM InVO₄ and 15CrO_x/bulk InVO₄, yCrO_x/3DOM InVO₄ showed much better visible-light-driven photocatalytic performance for RhB degradation, with the 15CrO_x/3DOM InVO₄ sample performing the best. It is concluded that the CrO_x loading, higher surface area and surface oxygen vacancy density and lower bandgap energy as well as the better quality of 3DOM structure were responsible for the good photocatalytic performance of 15CrO_x/3DOM InVO₄ for the degradation of RhB.