EAPSI: Fluid Flow-Assisted Assembly of Solar Cell Devices

有机光催化剂（OPV）作为一种太阳能转换技术具有很大的前景，它可以很容易地大规模生产，而且价格便宜，可以以与传统燃煤电厂相当的价格提供电力。此外，使用柔性基板的潜力为太阳能电池与建筑和城市基础设施的整合提供了新的机会。虽然OPV的优势很有吸引力，但该技术刚刚起步，尚未达到超过10%的功率转换效率。实现必要效率所固有的大多数关键物理特性发生在由有机聚合物半导体组成的器件的有源层中。该项目旨在通过研究在分子尺度上控制活性层的组装和组织的益处来提高器件效率。本研究将由国立台湾大学吴志毅教授指导，吴教授在OPV和类似半导体技术方面拥有丰富的经验，非常适合主持本研究。OPV有源层的关键过程包括通过光吸收产生电荷载流子，以及由于激子扩散、解离和传输到相对接触而收集电荷载流子。激子？兴奋，但仍然结合对积极和消极的电荷载体？在有机材料中，与典型的固态光伏半导体中的电荷传输相比，具有相对低的扩散长度和迁移率。因此，为了增加光子与材料的相互作用而增加有源层厚度的策略会由于载流子复合而导致效率损失，通常会否定该策略。的意图。一种这样的解决方案是通过将金属纳米颗粒整合到聚合物基质中来增加有效光学厚度，同时保持最小的物理厚度。然而，诸如此类的解决方案仍然经常通过旋涂来沉积，这提供了对活性层厚度的优异控制，但对中尺度结构几乎没有控制。伊利诺伊大学厄巴纳-香槟分校最近的工作表明，由于微流体的分子排列，有机半导体聚合物的光电性能得到了增强。本研究旨在通过微流控定向组装合成掺杂金属纳米颗粒来实现前所未有的效率。这个NSF EAPSI奖是与台湾科技部合作资助的。

Organic photovoltaics (OPVs) hold great promise as a solar energy conversion technology which can be easily mass produced and is cheap enough to offer electricity at a price comparable to power generated from traditional coal-fired power plants. Furthermore, the potential for use with flexible substrates opens new opportunities for integration of solar cells with architecture and urban infrastructure. While the advantages of OPVs are attractive, the technology is just emerging from its infancy and has yet to reach power conversion efficiencies exceeding 10%. Most of the critical physics intrinsic to achieving the necessary efficiencies occur in the active layer of a device which is composed of organic polymer semiconductors. This project aims to improve device efficiency by investigating the benefits of controlling the assembly and organization of the active layer at the molecular scale. The research will be conducted under the mentorship of Professor Chih-I Wu at National Taiwan University who has extensive experience with OPVs and similar semiconductor technology and is ideally suited to host this research.Critical processes in the OPV active layer include charge-carrier generation through light absorption and charge-carrier collection due to exciton diffusion, dissociation, and transport to opposite contacts. Excitons?excited, yet still bound pairs of positive and negative charge carriers?in organic materials have relatively low diffusion lengths and mobilities compared to charge transport in typical solid-state photovoltaic semiconductors. As such, the strategy of increasing active layer thickness in order to increase photon interaction with the material leads to lost efficiency due to carrier recombination, often negating the strategy?s intentions. One such solution is to increase effective optical thickness while retaining minimal physical thickness by integration of metallic nanoparticles into the polymer matrix. Solutions such as this, however, are still often deposited by spin-coating, which provides excellent control of active layer thickness, but little control with regard to mesoscale architecture. Recent work at the University of Illinois at Urbana-Champaign has demonstrated enhancement of optoelectronic properties in organic semiconducting polymers due to molecular alignment via microfluidics. This research aims to achieve unprecedented efficiencies through the synthesis of metallic nanoparticle doping with microfluidic directed assembly. This NSF EAPSI award is funded in collaboration with the Ministry of Science and Technology of Taiwan.