This Materials World Network award supports an international team of researchers at Cornell (US), Imperial College (UK) and Oxford University (UK) to investigate the synthesis and characterization of novel classes of metal-based nano-structured particles and composites with well-defined geometry and connectivity. The materials are obtained by a modular bottom-up approach of metal-containing nanoparticles (NPs) with core-shell architecture as well as nanocomposites from metal NPs and block copolymers (BCs) as structure-directed agents. The aim of the program is to understand the underlying fundamental chemical, thermodynamic and kinetic formation principles enabling general and relatively inexpensive wet-chemistry methodologies for the efficient creation of multiscale functional metal materials with novel optical property profiles that may revolutionize the field of nanophotonics/plasmonics/ metamaterials, enabled by nm-scale control over the underlying structure over large dimensions. The proposed research includes synthesis of all necessary organic/polymer and inorganic components, characterization of assembly structures using various scattering, optical and electron microscopy techniques, as well as thorough investigations of their optical properties including simulation and modeling efforts, and work towards major novel optics in the form of sub-wavelength imaging, highly sensitive hot-spot arrays over macroscopic dimensions for sensing, and sub-wavelength waveguiding. While the main focus of the work lies on non-magnetic materials and the assessment of linear optical properties of the fabricated compounds, a crucial point of the investigations is finding synthesis approaches that can be generalized over a wider class of materials systems. A final thrust of the program addresses a particularly topical exploitation area, integrating specific plasmonic structures into hybrid solar cells and characterizing and optimizing plasmon enhanced photogeneration of charges and subsequent solar cell efficiency.
Understanding the fundamental principles for successfully combining nanomaterials science with photonics/plasmonics in order to exert control over electromagnetic waves in deep sub-wavelength volumes will have profound impact in a broad range of areas. If successful, the project will provide advanced molecular design concepts for the next generation nanostructured materials in applications such as nanowaveguiding, single-molecule sensing and power generation (photovoltaics). Furthermore, discovering soft-matter, bottom-up approaches to co-assemble polymers and ceramics with metals could enable completely novel ways to organize matter into structures with functionalities not previously available. Team members are well-qualified bringing together unique expertise in the areas of hybrid materials synthesis and characterization, plasmonics and photovoltaics. The research project draws on a number of traditionally separated scientific disciplines, combining materials science with optics/nanophotonics and optoelectronics, thus providing a unique educational experience for students of all levels. The international collaboration will integrate research and education through a suite of proposed programs including international student exchanges, development of cyberinfrastructure, the participation of underrepresented groups, enhancement of infrastructure for research and education, and industrial outreach.
an international team of researchers at Cornell (US), Imperial Colloge (UK) and Oxford (UK) collaborated on the synthesis and characterization of, and structure-property correlation studies for, novel classes of metal-based nanostructured particles and metal-block polymer composites with emphasis on optical/plasmonic properties as well as on photovoltaic devices with light harvesting elements. The aim of the proposed program was to understand the underlying fundamental chemical, thermodynamic and kinetic formation principles enabling general and relatively inexpensive wet-chemistry methodologies for the efficient creation of multiscale functional metal materials with novel optical property profiles leading to significant advances in the fields of nanophotonics/plasmonics/metamaterials and photovoltaics. The team worked well together as documented by a number of co-authored publications and made significant advances in this interdisciplinary field that would have not been possible as individual PIs. The program made effective use of facilities like the Cornell Center for Materials Research (CCMR), the Cornell High Energy Synchrotron Source (CHESS) and the Cornell Nanofabrication Facility (CNF) as well as facilities at Imperial College, London, and Oxford University. Intellectual merit of the proposed activity. Understanding the fundamental principles for successfully combining nanomaterials science with photonics/plasmonics in order to control electromagnetic waves in nanometer sized sub-wavelength volumes has profound impact in a broad range of areas. Fore example, work in this project focused on the spontaneous assembly of polymeric structures into three-dimensionally continuous porous network structures on the nanoscale that could be backfilled with metals. In turn, this allowed, for the first time, elucidation of the propagation of light through such metallic nanostructures. As a comparison, without such nanostructures, propagation of electromagnetic waves (i.e. light) through metallic films does not take place. Results of the investigations in this project of the linear as well as the non-linear properties of such metallic nanostructures opened the door to the future generation of novel optical switches or enhanced sensors. Furthermore, studies in this program on photovoltaic cells incorporating metallic nanoparticles revealed fundamentally novel enhancement mechanisms leading to higher efficiency solar cells. The move to organic-inorganic hybrid perovskite solar cells in the last part of the project lead to particularly exciting results with cell efficiencies over 15%, thus making such materials viable for commercialization. Broader impacts resulting from the proposed activity. The research program drew from on a number of traditionally separated scientific disciplines, combining materials science with optics/nanophotonics and optoelectronics, thus providing a unique educational experience for all participating students. The international collaboration provided students with different perspectives on research from different institutions and different countries. In particular, the team worked with the excellent and proven platform provided by the NSF-funded Cornell Center for Materials Research (CCMR). The team worked on modules for, and workshops with, local high school teachers and students of the entire STEM pipeline in order to promote issues related to materials science and engineering. The proposed program synergistically built on an established collaboration on hybrid photonic materials between Cornell and Norfolk State University, VA, a Historically Black College/University (HBCU) with a large participation of underrepresented minorities, through the NSF PREM program.
