EAGER: Novel Interfaces for Nanostructured Solar Cells

染料敏化太阳能电池（DSSC）是一种有前途的低成本太阳能转换技术，其中吸附在半导体上的染料分子吸收光，将光注入的电子注入半导体（被氧化），并被溶解的碘化物还原（再生），得到中性染料和三碘化物。电子从半导体收集，通过外部电路，并返回到反电极，在那里它将三碘还原为碘，完成电路。碘化物还原氧化染料需要很大的过电位（至少0.5V），这在DSSC中构成了显著的能量损失。可以用小得多的过电位还原氧化染料的替代氧化还原对倾向于以高速率从半导体去除电子，用另一个损失过程代替一个损失过程。克服后一个问题（复合）需要增加半导体中电子传输的速度，以便在电子因复合而丢失之前提取电子。这个探索性的项目将产生初步的数据，以证明新的复合半导体纳米结构的潜力，以解决这个问题。智力MeritThe设计范式，管理这项工作是配对的两个半导体材料：一个活性层上的染料分子吸附和注入电子，和一个传输层，从活性层提取电荷，并迅速将其传输到导电基板收集。活性层必须具有高的表面积，以允许每个几何面积的大染料负载，用于入射太阳光的强吸收。在这项工作中将产生两个范例。一种是由包覆在氧化锌纳米棒上的二氧化钛纳米颗粒组成;纳米棒提供快速传输，而纳米颗粒大大增加了总表面积。另一种是在掺氟氧化锡（FTO）气凝胶上的二氧化钛保形层。气凝胶固有地是高表面积结构，允许活性层的保形涂层。该项目的重点是关于阻挡层以阻止复合的初步数据，FTO气凝胶样品中氟掺杂剂水平的分析，以及用新型复合半导体薄膜制成的太阳能电池器件的光电测量。面对大量人口中急剧增加的能源使用以及即将发生的气候变化和化石燃料燃烧造成的其他环境影响，对能源的需求日益迫切。该项目将为参与的研究生提供教育和培训，包括撰写研究文章和前往国内和国际会议传播成果。PI积极吸引K-12学生和教师使用DSSC作为与能源，环境，化学和工程相关主题的教学工具。

The dye-sensitized solar cell (DSSC) is a promising technology for low-cost solar energy conversion in which a dye molecule adsorbed on a semiconductor absorbs light, injects a photoinjected electron into the semiconductor (becoming oxidized), and is reduced (regenerated) by dissolved iodide, giving the neutral dye and triiodide. The electron is collected from the semiconductor, travels through an external circuit, and is returned to a counterelectrode where it reduces triiodide to iodide, completing the circuit. The reduction of oxidized dyes by iodide requires a large overpotential (at least 0.5 V), constituting a significant energy loss in the DSSC. Alternative redox couples that can reduce oxidized dyes with much smaller overpotentials tend to remove electrons from the semiconductor at high rates, replacing one loss process with another. Surmounting this latter problem (recombination) requires increasing the speed of electron transport in the semiconductor, in order that the electron may be extracted before it is lost to recombination. This exploratory project will generate preliminary data to demonstrate the potential for new composite semiconductor nanostructures to solve this problem.Intellectual MeritThe design paradigm that governs this work is the paring of two semiconducting materials:an active layer on which dye molecules adsorb and inject electrons, and a transport layer that extracts charges from the active layer and rapidly transports them to the conducting substrate for collection. The active layer must have a high surface area to allow a large dye loading per geometric area for strong absorption of incident sunlight. Two instances of this paradigm will be produced in this work. One consists of titania nanoparticles coated over zinc oxide nanorods; the nanorods provide fast transport while the nanoparticles greatly increase the total surface area. The other is a conformal layer of titania over a fluorine-doped tin oxide (FTO) aerogel. The aerogel is inherently a high-surface area structure, allowing a conformal coating of the active layer. This project focuses on preliminary data regarding blocking layers to retard recombination, analysis of fluorine dopant levels in FTO aerogel samples, and optoelectronic measurements of solar cell devices made with the novel composite semiconductor films.Broader ImpactsThis research will significantly advance the technology of low-cost solar energy conversion, for which there is an increasingly urgent need in the face of sharply increasing energy usage among a large population together with impending climate change and other environmental impacts from fossil fuel combustion. The project will provide education and training to involved graduate students including the writing of research articles and travel to domestic and international conferences for dissemination of the results. The PI actively engages K-12 students and teachers using the DSSC as a teaching tool for topics related to energy, the environment, chemistry and engineering.