Quantum dot-sensitized solar cells employing Pt/C60 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.     

Chlorophyll a photoelectrochemical cells with different metal electrodes

A photosensitive electrode was prepared by electrodepositing a membrane of chlorophyll a (Chla) on a SnO2 optical transparent electrode,with which and a metal counter electrode a Chla photoelectrochemical cell was formed.Photoinduced current (Ii) and photoinduced voltage (Vi) of the cell were measured.The dependence of Ii on the properties of metal electrodes was obvious,which was illustrated with mechanism of Chla photoelectrical effects Ii in this work was as high as 2×10-5 A·cm-2.     

掺杂纳米金粒子的火焰氧化TiO2膜的光电化学性质的研究

A nano-Au modified TiO2 electrode was prepared via the oxidation of Ti sheet in flame and subsequent modification with gold nanoparticles. The results of SEM and TEM measurements show that the Au nanoparticles are well dispersed on TiO2 surface. A near 2-fold enhancement in photocurrent was achieved upon the modification with Au nanoparticles. From the results of photocurrent and electrochemical impedance experiments it was found that the flatband potential of nano-Au/TiO2 electrode negatively shifted about 100 mV in 0.5 mol/L Na2SO4 solutions compared with that of bare TiO2 electrode. The improvement of photoelectrochemical performance was explained by the inhibition for charge recombination of photo-induced electrons and holes, and the promotion for interracial charge-transfer kinetics at nano-Au/TiO2 composite film. Such nanometal-semiconductor composite films have the potential application in improving the performance of photoelectrochemical solar cells.     

Novel Quasi-solid-state Dye-sensitized Solar Cell Based on Monolayer Capped TiO2 Nanoparticles Framework Materials

Dodecylbenzenesulfonate (DBS)-capped TiO2 nanoparticles have been synthesized and employed in dye-sensitized solar cells to form a quasi-solid state electrolyte. Owing to the long alkyl-chain capping around the TiO2 nanoparticles interacting with the liquid solvent, the dye sensitized solar cell based on such DBS-capped TiO2 nanoparticle framework material gel electrolyte shows higher stability compared with the non-capped one in the long-term application and gives a comparable overall efficiency of 6.3% at AM 1.5 illumination.     

Influence of Modification of Counter Electrode on Photoelectric Properties of Dye-sensitized TiO2 Solar Cells

A dye-sensitized nanocrystalline TiO2 solar cell(DYSC) was assembled, of which counter electrode was modified already by platinum, nickel and carbon. It was found that the DYSC had better photoelectric performance when the electrode was modified by platinum than by nickel and carbon. The influence of the incidence light wavelength on the incidence monochromatic photoelectric conversion effieieney(IPCE) was investigated.The result shows that the IPCE mainly depends on the short-circuit current density(Isc) of a DYSC, and the IPCE reaches 48.32% under the irradiation with the wavelength of 560 nm when the counter electrode of a DYSC was modified by platinum. The influence of incident light intensity on the photoelectric properties of a DYSC was also investigated. It was found that the Isc and open-circuit voltage(Voc) increased and the fill factor(ff) of the DYSC decreased with the increase of the incident light intensity.     

Efficiency improvement of flexible dye-sensitized solar cells by introducing mesoporous TiO2 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.     

Dye-sensitized solid-state solar cells fabricated by screen-printed TiO_2 thin film with addition of polystyrene balls

The screen-printed nanoporous TiO2 thin film was employed to fabricate dye-sensitized solid-state solar cells using CuI as hole-transport materials. The solar cell based on nanoporous TiO2 thin film with large pores formed by the addition of polystyrene balls with diameter of 200 nm to the TiO2 paste exhibits photovoltaic performance enhancement, which is attributed to the good contact of CuI with surface of dye-sensitized thin film due to easy penetration of CuI in the film with large pores.     

A Novel Composite Electrode of Photocatalyst—TiO2／C Loading on the Surface of the Air （Oxygen） Electrode

The methods for preparing the H2O2 generating air (oxygen) electrode and the composite electrode of photocatalyst-TiO2/C loading on the surface of the air (oxygen) electrode were introduced.In the case of the composite electrode,the current efficiency of electro-generated H2O2 is higher than 80%(J≤15mA/cm^2).The degradation of aniline was used as an example to measure the influence of the composite electrode and compared with the system in which the air (oxygen) electrode and the photocatalyst-TiO2 were sqparated.The results confirmed that the composite electrode played an active role on accelerating the degradation rate of aniline.According to the measurement of the polarization curves of composite electrode and TiO2 photo anode,and of the adsorbing amount of aniline on the surface of the composite electrode,the principle of descending the recombination reta of photo-generated electron and hole and of enhancing the oxidation rate of organic molecule was described.The mechanism about the degradation of aniline was also discussed.     

High dispersion Pt nanoparticles using mesoporous carbon support for enhancing conversion efficiency of dye-sensitized solar cells

<正>Mesoporous carbon(MC) with surface area of 380 m~2/g was prepared and employed as the carbon support of Pt catalyst for counter electrode of dye-sensitized solar cells.Pt/MC samples containing 1 wt%Pt were prepared by reducing chloroplatinic acid on MC using wet impregnation.It was found that Pt nanoparticles were uniform in size and highly dispersed on MC supports.The average size of Pt nanoparticles is about 3.4 nm.Pt/MC electrodes were fabricated by coating Pt/MC samples on fluorine-doped tin oxide glass.The overall conversion efficiency of dye-sensitized solar cells with Pt/MC counter electrode is 6.62%,which is higher than that of the cells with conventional Pt counter electrode in the same conditions.     

Low Sheet Resistance Counter Electrode in Dye-sensitized Solar Cell

In order to search for the high efficiency and low sheet resistance counter electrode indye-sensitized solar cell, we used Ti plate as the conducting substrate to prepare the counterelectrode by thermal decomposition of H2PtC16. Ti plate counter electrode shows low sheetresistance, good reflecting performance and matching kinetics. The dye-sensitized solar cell with theTi plate counter electrode shows better photovoltaic performance than that of the cell with thefluorine-doped tin oxide-coated glass counter electrode.     

TiO2/SnO2复合空心球在染料敏化太阳能电池中的应用

采用模板辅助法制备了SnO2/TiO2复合空心球,样品直径为1.5~4.0μm,比表面积达到了92.9 m^2·g^-1,复合空心球表现出优越的光散射性能.以这种复合空心球作为染料敏化太阳能电池的光阳极,电池的光电转换效率可达到7.72%,高于SnO2微米球(2.70%)和TiO2微米球(6.26%).此外,以锐钛矿型TiO2纳米晶作为底层,SnO2/TiO2复合空心球作为光散射层制备的双层结构光阳极,电池光电转换效率进一步提升至8.43%.     

纳米SnO2@TiO2包覆催化剂的制备及表征

采用活性层包覆法在自制细SnO2胶体粒子表面包覆TiO2,制备出SnO2@TiO2包覆型复合催化剂,以其对有机磷农药DDVP的降解效果作为评价光催化活性的标准,对制备条件进行了优化,并用XRD、TEM和BET等手段对样品进行了表征,结果表明,SnO2胶体乙醇溶液含水量20％,钛酸丁酯质量分数为34.5％。灼烧温度680℃时制得TiO2含量56.45％的包覆样品SnO2@TiO2为纳米级粒子,且其光催化活性最佳。     

TiO2/SnO2复合光催化剂的耦合效应

采用改进的sol gel技术制备TiO2/SnO2耦合型半导体光催化剂,利用XRD、气相色谱 仪、粒度仪和表面光电压装置等研究了耦合型半导体光催化机理和光催化效率的影响因素, 并通过降解甲醛探讨其在空气污染治理中的作用.实验结果表明,添加20 ％(mol) SnO2的复 合半导体光催化剂,其光催化效率比纯TiO2高一倍以上.据实验结果和粒子紧密堆积原理,提 出强耦合效应和弱耦合效应的光催化反应模型,并用此模型较好地解释了TiO2/SnO2复合型半 导体光催化剂的光催化效率随SnO2含量变化规律.     

Porphyrin-sensitized nanoparticulate TiO2 as the photoanode of a hybrid photoelectrochemical biofuel cell

Porphyrin-sensitized nanoparticulate TiO(2) on conducting glass has been investigated as a photoanode material for a new cell that converts light energy into electricity. The cell is a hybrid of a dye-sensitized nanoparticulate semiconductor photoelectrochemical solar cell, and a biofuel cell that oxidizes glucose. Porphyrin molecules excited by light inject electrons into the photoanode, from where they enter the external circuit. The resulting porphyrin radical cations are reduced by NADH in aqueous buffer, ultimately regenerating the photoanode and producing NAD(+). Glucose dehydrogenase oxidizes glucose, and in the process recycles NAD(+) back to NADH. The photoanode is coupled with a suitable cathode to make a functioning cell (Hg/Hg(2)SO(4) was employed for evaluation purposes). The cell produces 1.1 V at open circuit and has a fill factor of 0.61. These values are both significantly higher than those for a previously reported cell of a similar type based on an SnO(2) electrode.     

TiO2／SnO2复合光催化剂的耦合效应

采用改进的 sol-gel技术制备ＴiO2/SnO2耦合型半导体光催化剂,利用ＸＲＤ、气相色谱仪、粒度仪和表面光电压装置等研究了耦合型半导体光催化机理和光催化效率的影响因素,并通过降解甲醛探讨其在空气污染治理中的作用。实验结果表明,添加20％（mol)SnO2的复合半导体光催化剂,其光催化效率比纯TiO2高一倍以上。据实验结果和粒子紧密堆积原理,提出强耦合效应和弱耦合效应的光催化反应模型,并用此模型较好地解释了TiO2/SnO2复合型半导体光催化剂的光催化效率随SnO2 含量变化规律。     

Preparation of nanoporous MgO-coated TiO2 nanoparticles and their application to the electrode of dye-sensitized solar cells

Sol-gel-derived Mg(OH)(2) gel was coated onto TiO(2) nanoparticles, and the subsequent thermal topotactic decomposition of the gel formed a highly nanoporous MgO crystalline coating. The specific surface area of the electrode that was prepared from the core-shell-structured TiO(2) nanoparticles significantly increased compared with that of the uncoated TiO(2) electrode. The increase in the specific surface area of the MgO-coated TiO(2) electrode was attributed to the highly nanoporous MgO coating layer that resulted from the topotactic reaction. Dye adsorption behavior and solar cell performance were significantly enhanced by employing the MgO-coated TiO(2) electrode. Optimized coating of a MgO layer on TiO(2) nanoparticles enhanced the energy conversion efficiency as much as 45% compared to that of the uncoated TiO(2) electrode. This indicates that controlling the extrinsic parameters such as the specific surface area is very important to improve the energy conversion efficiency of TiO(2)-based solar cells.     

Photoinduced electron injection from Ru(dcbpy)2(NCS)2 to SnO2 and TiO2 nanocrystalline films

Photoinduced electron injection from the sensitizer Ru(dcbpy)2(NCS)2 (RuN3) into SnO2 and TiO2 nanocrystalline films occurs by two distinct channels on the femto- and picosecond time scales. The faster electron injection into the conduction band of the different semiconductors originates from the initially excited singlet state of RuN3, and occurs in competition with intersystem crossing. The rate of singlet electron injection is faster to TiO2 (1/55 fs-1) than to SnO2 (1/145 fs-1), in agreement with higher density of conduction band acceptor states in the former semiconductor. As a result of competition between the ultrafast processes, for TiO2 singlet, whereas for SnO2 triplet electron injection is dominant. Electron injection from the triplet state is nonexponential and can be fitted with time constants ranging from approximately 1 ps (2.5 ps for SnO2) to approximately 50 ps for both semiconductors. The major part of triplet injection is independent of the semiconductor and is most likely controlled by intramolecular dynamics in RuN3. The overall time scale and the yield of electron injection to the two semiconductors are very similar, suggesting that processes other than electron injection are responsible for the difference in efficiencies of solar cells made of these materials.     

Morphology evolution effects on electrochemical activity of hierarchically stacking SnO2-Sb/TiO2-NTs electrode prepared by the hydrothermal method

Journal of Solid State Electrochemistry - Distinct three-dimensional hierarchically stacking SnO2-Sb/TiO2-NTs electrode with a good-adhesion TiO2-NTs@SnO2-Sb interlayer, a compact plate SnO2-Sb...     

Morphological and photoelectrochemical characterization of core-shell nanoparticle films for dye-sensitized solar cells: Zn-O type shell on SnO2 and TiO2 cores

Core-shell type nanoparticles with SnO2 and TiO2 cores and zinc oxide shells were prepared and characterized by surface sensitive techniques. The influence of the structure of the ZnO shell and the morphology ofnanoparticle films on the performance was evaluated. X-ray absorption near-edge structure and extended X-ray absorption fine structure studies show the presence of thin ZnO-like shells around the nanoparticles at low Zn levels. In the case of SnO2 cores, ZnO nanocrystals are formed at high Zn/Sn ratios (ca. 0.5). Scanning electron microscopy studies show that Zn modification of SnO2 nanoparticles changes the film morphology from a compact mesoporous structure to a less dense macroporous structure. In contrast, Zn modification of TiO2 nanoparticles has no apparent influence on film morphology. For SnO2 cores, adding ZnO improves the solar cell efficiency by increasing light scattering and dye uptake and decreasing recombination. In contrast, adding a ZnO shell to the TiO2 core decreases the cell efficiency, largely owing to a loss of photocurrent resulting from slow electron transport associated with the buildup of the ZnO surface layer.     

SnO2TiO2 复合半导体纳米薄膜的研究进展*

本文概述了SnO₂TiO₂ 复合半导体纳米薄膜的发展历史和研究现状,对比分析了“混合”、“核壳”和“叠层”3 种复合薄膜的结构和性能特点,着重论述了叠层结构的SnO₂ /TiO₂复合薄膜的光电化学和光催化特性。结合作者的研究工作,探讨了SnO₂ /TiO₂双层复合薄膜上下层厚度对其光催化活性的影响,指出复合薄膜光催化活性的提高可归因于电子从TiO₂ 向SnO₂ 的迁移。最后对SnO₂ /TiO₂复合薄膜的局限性和发展潜势做一简要分析,强调了该复合薄膜本身的应用特点。