International Research Fellowship Program: Design, Synthesis and Characterization of Novel Conduction Polymers for Dye-sensitized Solar Cells

0601913白色国际研究奖学金计划使美国科学家和工程师能够在国外进行9至24个月的研究。该计划的奖项提供了联合研究的机会，以及使用独特或互补的设施，专业知识和国外的实验条件。白色与巴西坎皮纳斯大学的马尔科-奥雷利奥·德保利博士一起工作。该项目得到了国际科学与工程办公室（OISE）美洲项目的支持。随着对可再生能源需求的增长，染料敏化太阳能电池（DSSC）正在成为60多年前开发和商业化的传统硅电池的可行替代品。最著名的DSSC是Gratzel电池，其总效率可达~ 10%。在该电池的生产中取得的一个主要进步是并入高表面积的中孔金属氧化物材料。这增加了给定区域内与表面接触的染料分子的量。虽然这些类型的电池已经在商业上证明了这些类型的电池的潜在活力，但是由于所需的反应性电解质以及昂贵的染料分子前体，它们的制造被证明是困难和昂贵的。在De保利博士的实验室和其他实验室中，共轭聚合物材料已被用作光敏染料和电解质。这些聚合物在成本和耐久性方面比小分子具有明确的优势，同时显示出与Gratzel细胞染料分子相似的吸收特性。迄今为止，含有聚合物染料的DSSC具有相对低的转化效率。本计画的目标是开发具有更有效电荷传输特性的高分子染料材料，并制造更有效的DSSC。通过将共轭聚合物膜共价连接到无机基底，实现了更好的轨道重叠，并且增加了电子注入电路的速率。可以改变染料单体和连接体的特性以优化注射过程。为了定量研究电子注入特性，合成了不同无机纳米颗粒-连接剂-染料组合的模型化合物。这通过用羧酸或膦酸基团修饰共轭单体分子如噻吩来实现，所述羧酸或膦酸基团可以锚在金属氧化物纳米颗粒表面上。这些化合物的电子转移速率可以通过时间分辨的激光闪光光解吸收和荧光技术直接研究。为了将聚合物染料附着到无机层，共轭染料单体通过锚定基团附着到无机表面并通过化学和电化学手段聚合。光电响应和这些新型DSSC的效率进行了分析的电化学仪器在德保利博士的实验室。

0601913WhiteThe International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support a twenty-two-month research fellowship by Dr. Ryan C. White to work with Dr. Marco-Aurelio De Paoli at the University of Campinas in Brazil. Support for this project comes from the Office of International Science and Engineering's (OISE) Americas Program.As the need for renewable energy resources grows, dye-sensitized solar cells (DSSCs) are emerging as a viable alternative to the traditional silicon cells developed and commercialized over 60 years ago. The most well known DSSC is the Gratzel cell which can reach an overall efficiency of ~10%. One major advance made in the production of this cell is the incorporation of high surface area mesoporous metal oxide materials. This increases the amount of dye molecules in contact the surface in for a given area. While these types of cells have proved the potential viability of these types of cells commercially, their fabrication proves difficult and expensive due to the reactive electrolyte needed, as well as expensive dye molecule precursors. In the Dr. De Paoli's laboratory, and others, conjugated polymeric materials have been used as the both photoactive dyes and electrolytes. These polymers have definite advantages over small molecules in cost and durability, while showing similar absorption characteristics of Gratzel cell dye molecules. To date the DSSC's containing polymeric dyes have had relatively low conversion efficiencies. The goal of this project is to develop polymeric dye materials with more efficient charge transport properties and to fabricate more efficient DSSCs. By covalently attaching the conjugated polymer film to the inorganic substrate, better orbital overlap is achieved and the rate of electron injection into the electrical circuit is increased. The identity of both the dye monomer and linker can be changed to optimize the injection process. To quantitatively study the electron injection properties, model compounds are synthesized of different inorganic nanoparticle-linker-dye combinations. This is accomplished by modifying conjugated monomers molecules such as thiophene with carboxylic or phosphonic acid groups which can anchor onto the metal oxide nanoparticle surface. Electron transfer rates of these compounds can be studied directly by time resolved laser flash photolysis absorbance and fluorescence techniques. To attach the polymeric dye to the inorganic layer, the conjugated dye monomers are attached to inorganic surfaces via anchoring groups and polymerized by chemical and electrochemical means. The photovoltaic responses and efficiencies of these novel types of DSSC's are analyzed by electrochemical instrumentation in Dr. De Paoli's laboratory.