Revelation of Structure-Property Relationships of Polymers Using Molecular Simulation

与化石燃料的能源生产有关的环境问题和飙升的原油价格一直是推动可再生能源开发的主要因素。事实上，地球上一小时的阳光照射所产生的能量比人类全年消耗的能量还要多，找到一种合适的方式来捕捉这种形式的能量，绝对可以永远解决人类的能源问题。80年代早期有机半导体的出现使得用聚合物制造太阳能电池成为可能。这些所谓的塑料太阳能电池的优点包括重量轻，化学结构的通用性，机械灵活性和易于加工（便宜）。然而，仍有两个主要的障碍需要克服，它们是能量转换效率（约8.3%，最新报告值）和耐用性（约1年）。预计效率达到10%或更高，设备寿命约为10年，将使该技术具有商业可行性。最近，各种研究人员的初步结果表明，共轭二嵌段共聚物可能有助于克服第一个障碍，因为这种材料具有高功率转换效率所需的各种可控纳米级形态。为了解决功率转换效率和耐久性问题，我建议使用多个三嵌段共聚物。基本的想法是，除了三嵌段共聚物的两个嵌段具有所需的电子性能外，第三个嵌段将对电极和/或传输层具有很强的亲和力，并且能够降低氧和水的扩散率，这些化合物被认为会导致聚合物太阳能电池活性层的降解。使用多种三嵌段共聚物将使太阳能电池吸收入射阳光的最大部分。特别是，我将应用分子模拟技术来研究各种三嵌段共聚物的结构-性能关系。预计在提议的工作中产生的见解将使我们能够更好地设计聚合物太阳能电池。

Environmental issues related to energy production from fossil fuels and soaring crude oil prices have been the main stimulants for the development of renewable energy resources. In fact, energy from one hour of sunlight striking on Earth is more than all of the energy consumed by mankind in an entire year and finding a suitable way to capture this form of energy could definitely solve energy concerns of the human race forever. Advent of organic semiconductors in the early 80s made it possible to fabricate solar cells from polymers. The advantages of these so-called plastic solar cells include lightweight, versatility of chemical structure, mechanical flexibility and ease of processing (inexpensive). However, there are still two major hurdles that need to be overcome and they are the power conversion efficiency (~ 8.3%, latest reported value) and durability (~ 1 year). It is expected that efficiencies of 10% or higher and device lifetimes of around 10 years will make this technology commercially viable. Most recently, preliminary results of various researchers have shown that conjugated di-block copolymers may help overcome the first hurdle as such materials exhibit a variety of controllable nano-scale morphology needed for high power conversion efficiency. To address both the power conversion efficiency and durability issues, I propose to use multiple tri-block copolymers. The basic idea is that beside the two blocks of the tri-block copolymers having the desired electronic properties, the third block will have strong affinity for the electrodes and/or transport layer and the ability to reduce the diffusivity of oxygen and water, the compounds that are believed to cause degradation of the active layer in polymer solar cells. Use of multiple tri-block copolymers will make the solar cell to absorb maximum portion of incident sunlight. In particular, I will apply molecular simulation techniques to study structure-property relationship of various tri-block copolymers. It is expected that insights generated in the proposed work will allow us to better design polymer solar cells.