Understanding and Controlling Structure in Metal Ion-Linked Multilayer Upconversion Solar Cells

Florida State University, Tallahassee FL

Investigators

Abstract

Nontechnical description: Interfaces between organic and inorganic materials are important for many applications. For example, biosensors operate at the interface between living matter and electronics. Hybrid perovskites with organic and inorganic components have shown great promise for high efficiency and low-cost solar cells. Hybrid materials consisting of alternating layers of organic and inorganic species linked by metal ions have shown promise for device applications. By varying the species and their interactions, it may be possible to tune the electronic and optical properties for a given application. Despite the importance of interfaces in these materials, there are fundamental questions about how the spacing, bonding, and orientation of molecules affect the properties of these metal ion linked multilayers. The goal of this research is to determine the structure of the multilayer assemblies and how that structure dictates their performance. Investigators will elucidate the properties of these structures by studying how polarized light is absorbed and emitted, combined with vibrational spectroscopy that detect oscillations of bound atoms. These studies will enable the rational design of structured multilayers with targeted properties for improved performance in solar cells, catalysis, sensing, and more. Complementing these research efforts are multifaceted outreach/education activities. These include engaging the public through online videos and social media, quantifying the impact of active learning on general chemistry courses, and developing a shared use facility in the PI’s laboratory and increasing awareness of its utility. Technical description: Metal ion-linked molecular multilayers on metal oxide surfaces have emerged as a simple and modular means of gaining unprecedented control over the properties of organic-inorganic interfaces and their application in hybrid devices. While distinct in their outcomes/goals, most hybrid devices rely on interfacial electron and energy transfer which in turn are dependent on the molecular level structure of the interface (i.e., the distance, bonding, and orientation between molecules). Unfortunately, that structure is largely unknown. The goal of the research here is to 1) use a combination of polarized attenuated total reflectance (p-ATR), emission anisotropy, Raman, and x-ray photoelectron spectroscopy to determine the structure of multilayer assemblies, 2) understand how the metal ion and binding motif impact the multilayer structure and performance in photon upconversion solar cells, and 3) transfer knowledge of the technique and build a p-ATR instrument in the FSU Spectroscopy Lab user facility for use by the greater research community. In total, successful completion of this work will provide the tools to measure interfacial structure and the fundamental insights necessary for the creation of designer multilayer interfaces for improved performance in solar cells, catalysis, molecular rectifiers, electrochromism, and more. 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.