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.     

Highly Efficient Photosensitization of Mesoporous TiO_2 Electrode with a Cyanine Dye

Dye-sensitized mesoporous TiO2 photoelectrochemical cell has attracted much interest for photoelectric conversion1,2. The most efficient charge transfer dye studied so far is Ru(dcbpy)2(NCS)2 (dcbpy=4, 4'-dicarboxy-2, 2'-bipyridine), with which IPCE of about unity has been achieved3. Considering the low cost, low toxicity, easy handling, non-metal complex dyes should also be right candidates. Here we report the highly efficient photosensitization of mesoporous TiO2 electrode with a nov…     

Visible‐Light‐Responsive Photoanodes for Highly Active,Stable Water Oxidation

Solar energy is a natural and effectively permanent resource and so the conversion of solar radiation into chemical or electrical energy is an attractive, although challenging, prospect. Photo‐electrochemical (PEC) water splitting is a key aspect of producing hydrogen from solar power. However, practical water oxidation over photoanodes (in combination with water reduction at a photocathode) in PEC cells is currently difficult to achieve because of the large overpotentials in the reaction kinetics and the inefficient photoactivity of the semiconductors. The development of semiconductors that allow high solar‐to‐hydrogen conversion efficiencies and the utilization of these materials in photoanodes will be a necessary aspect of achieving efficient, stable water oxidation. This Review discusses advances in water oxidation activity over photoanodes of n‐type visible‐light‐responsive (oxy)nitrides and oxides.     

CdTe/CdS共敏化TiO2电极材料的制备与光电性能

将电沉积法和化学浴沉积法结合,分别将CdTe和CdS量子点纳米晶材料引入到TiO_2纳米管阵列上制备CdTe/CdS量子点共敏化TiO_2光电极。利用扫描电镜、X射线衍射和X射线能量色散光谱等测试手段对所得样品的形貌、晶型和组分进行表征。在模拟太阳光照射条件下,通过电化学工作站测试其光电化学性能。研究结果表明,相对于单一量子点敏化CdS/TiO_2和CdTe/TiO_2光电极而言,共敏化CdTe/CdS/TiO_2光电极表现出更好的光电转化性能,短路电流密度和光电转换效率分别可以达到3.1 m A·cm~(-2)和1.85%。此外,采用电化学阻抗测试技术对材料性能提升的原因进行深入的探究。     

n型Cu2O薄膜的简易水热法制备及其光电化学性能

采用一种简单的水热法,通过控制反应时间,使用铜片在只含有Cl~-的非含铜前驱物的NaCl溶液中生长出了n型Cu_2O薄膜。对制备的样品进行了X射线衍射(XRD)、拉曼光谱(Raman)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)和光电化学等表征或测试。本水热法相对其他的水热法工艺更简单,成本更低且能进行快速大规模化的生产。且得到的n型Cu_2O薄膜晶化程度高,经过Cl~-掺杂后,载流子浓度高达9.75×10~(17) cm~(-3),在可见光照射下表现出较好的光电转换性能。光电化学和电化学阻抗谱表明在中等浓度(0.1 mol·L~(-1))NaCl溶液中90℃的条件下水热反应50 h制备的Cu_2O薄膜具有最好的光电性能。     

电解液成分、厚度及表面改性对旋涂法制备的BiVO4膜层光电化学性能的影响

采用旋涂法在FTO（SnO₂∶F）导电玻璃衬底上沉积得到BiVO₄多孔薄膜用以光解水,改变前驱体的浓度和旋涂次数以调控薄膜的厚度。研究了电解液成分、膜层厚度及表面改性等因素对刚经历过退火处理的BiVO₄薄膜光电化学（PEC）性能的影响。结果表明：通过在电解液中添加适量的空穴吞噬剂Na₂SO₃,或对表面进行Co-Pi改性均能有效改善BiVO₄薄膜的PEC活性。这些措施均能有效抑制固液界面处的载流子复合反应。经Co-Pi改性的BiVO₄薄膜在0.6 V（vs SCE）偏压下,0.1 mol·L^-1 Na₂SO₄+0.1 mol·L^-1 Na₂SO₃的电解液中展现出最高的光电流密度（4.3 mA·cm^-2）。此外,选用一个代表性BiVO₄薄膜作为光阳极制备了一个PEC生物传感器,在检测谷胱甘肽（GSH）上表现出比较高的灵敏度。本研究证实了BiVO₄薄膜的PEC性能严重依赖着光俘获效率和载流子输运过程。     

Photovoltaic performance of injection solar cells and other applications of nanocrystalline oxide layers

The direct conversion of sunlight to electricity via photoelectrochemical solar cells is an attractive option that has been pursued for nearly two decades in several laboratories. In this paper, we review the principles and performance features of very efficient solar cells that are being developed in our laboratories. These are based on the concept of dye-sensitization of wide bandgap semiconductors used in the form of mesoporous nanocrystalline membrane-type films. The key feature is charge injection from the excited state of an anchored dye to the conduction band of an oxide semiconductor such as TiO₂. In the use of the semiconductor in the form of high surface area, highly porous film offers several unique advantages: monomeric distribution of a large quantity of the dye in a compact (few micron thick) film, efficient charge collection and drastic inhibition of charge recombination (‘capture of charge carriers by oxidized dye’). Near quantitative efficiency for charge collection for monochromatic light excitation gives rise to sunlight conversion efficiency in the range of 8–10% This has led to fruitful collaboration with several industrial partners. Possible applications and commercialization of these solar cells and also other practical applications of nanosized films are briefly outlined.     

A Sol-Gel Type of Electrolyte for a Dye-Sensitized Solar Cell: Attenuated Total Reflectance (ATR) Vibrational Spectra Studies

Gel electrolytes based on triethoxy silane with a covalently linked mid-poly (propylene glycol) chain (ICS-PPG) and an incorporated KI + I₂ redox couple were prepared for use in a dye-sensitized photoelectrochemical cell (DSPEC). Infrared ATR spectra measurements of ICS-PPG and ICS-PPG/KI + I₂ catalyzed with HCl or AcOH were performed and the changes to the vibrational bands of the solvent (EtOH), the urea groups and the SiOEt groups were used to correlate the hydrolyzing effect of HCl and AcOH, strengthening the interactions between urea groups during gelation and the evaporation of EtOH. The measurements of the I/U characteristics of the DSPEC with ICS-PPG/KI + I₂/HCl and ICS-PPG/KI + I₂/AcOH showed that the cell with the latter type of electrolyte exhibited a higher efficiency, which was related to the influence of indirect hydrolysis in the case of the AcOH catalyst. ATR spectra analysis confirmed the hydrolyzing effect of AcOH on ICS-PPG, which involved the anionic substitution of the acetyl radical.