Direct Chiro-Optical Detectors Based on Organic Semiconductors

基于有机半导体的直接光电探测器探测光的偏振为生物学研究、量子光学、环境监测和导航提供关键信息。然而，目前检测圆偏振光(CPL)的方法需要庞大的滤光片或复杂的等离子体纳米结构，这阻碍了CPL探测器的小型化和可扩展制造。为了克服这些缺点，该项目旨在利用手性有机半导体创造新的器件，提供直接捕获CPL特征的转化能力。这项研究将阐明决定手性半导体偏振响应的基本机制，并利用新的见解实现紧凑、低成本的器件，从而极大地扩大偏振敏感探测器的实现。丰富的偏振信息将使新的分析在科学、医学、工业和国防应用中成为可能。该项目将包括外展活动，包括为暑期课程开发新的工作坊材料和为K-12学生开发科学工具包。该项目将研究新的设备架构，以确定放大有机半导体的光电响应的设计指南。尽管手性有机半导体已经表现出很强的手性光学响应，但与CPL的不对称相互作用的起源仍然不完全清楚，特别是关于介观设计的贡献。因此，这一提议的目的是解释介观有序性对手性光学响应的基本影响，并增加半导体对目标CPL利手的灵敏度和选择性。这里提出的方法是使用一个双层结，它将光生和电荷传输过程解耦，从而使手性吸收层和传输层可以独立优化。在第一个项目目标中，(1)有机手性吸收体和氧化物传输半导体之间的电子相互作用将被操纵，以促进电荷注入和触发光电倍增，从而显著提高传感器的探测率。接下来，(2)通过组装用于吸收层的手性介观结构，将提高传感器对CPL利手性的选择性。通过定制的电纺技术，可以精确地修改结构参数，以确定阻碍器件性能达到理论不对称极限的因素。对于第三个目标，(3)将线偏振和圆偏振器件集成到一个超像素中将提供互补信号，这些信号对于提取次表面特征和提高背向散射光测量的深度分辨率至关重要。预期的项目成果是获得基础知识，澄清手性有机半导体的结构-性质-加工关系，以便将此类材料设计成便携式、负担得起的CPL探测器，以利用偏振敏感应用中的丰富机会。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Direct Chiro-Optical Detectors Based on Organic SemiconductorsDetecting the polarization of light provides critical information for biological studies, quantum optics, environmental monitoring and navigation. However, current methods for sensing circularly polarized light (CPL) require bulky filters or complex plasmonic nanostructures that preclude miniaturization and scalable fabrication of CPL detectors. To overcome these shortcomings, this project aims to create novel devices using chiral organic semiconductors that provide the transformative capability to directly capture CPL characteristics. The research will clarify fundamental mechanisms that dictate polarization response in chiral semiconductors and use the new insights to realize compact, low-cost devices that can vastly expand implementations of polarization-sensitive detectors. The rich polarization information will empower new analyses in scientific, medical, industrial, and defense applications. This project will incorporate outreach activities, including the development of new workshop materials for summer programs and science kits for K-12 students.This project will study new device architectures to determine design guidelines for amplifying the chiro-optical response of organic semiconductors. While chiral organic semiconductors have shown strong chiro-optical response, the origins of the dissymmetric interactions with CPL are still not fully understood, particularly with respect to the contributions from mesoscopic designs. Thus the goal of this proposal is to explain the fundamental effects of mesoscopic ordering on chiro-optical response and increase the semiconductor sensitivity and selectivity to a target CPL handedness. Here the proposed approach is to use a bilayer junction which decouples the photogeneration and charge transport processes so that the chiral absorber and the transport layer can be independently optimized. In the first project objective, (1) the electronic interactions between the organic chiral absorber and the oxide transport semiconductors will be manipulated to facilitate charge injection and trigger photomultiplication to significantly raise sensor detectivity. Next, (2) the sensor selectivity to the CPL handedness will be enhanced by assembling chiral mesoscopic structures for the absorber layer. Through custom electrospinning techniques, the structural parameters can be modified precisely to identify factors that hinder the device performance from reaching the theoretical dissymmetry limit. For the third objective, (3) the integration of linearly and circularly polarized devices into a super-pixel will provide complementary signals that are crucial for extracting sub-surface features and improving depth resolution of back-scattered light measurements. The expected project outcome is to gain foundational knowledge clarifying the structure-property-processing relations for chiral organic semiconductors, so this class of materials can be engineered into portable, affordable CPL detectors to harness the rich opportunities in polarization-sensitive applications.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.