Inorganic-organic molecular junctions formed by trapping organic molecules between inorganic electrodes are expected to have novel transport properties that are unlike that of organic materials or inorganic materials. Using inorganic-organic hybrid materials made of such junctions, it may be possible to develop cost-efficient thermoelectric and photovoltaic devices. However, to create these revolutionary technologies, it is essential to first understand the dependence of heat and charge transport properties of molecular junctions on: 1) the molecular structure of the organic molecule trapped between the electrodes, and 2) the chemical composition and resulting crystal structure of the electrodes. This proposal aims to understand this structure-property relationship by experimentally studying heat and charge transport in molecular junctions.
Intellectual Merit: This program will provide new insights into the nature of heat and charge transport phenomena that occur in nanometer-sized molecular junctions due to the confinement of phonons and electrons in them. A novel technique that will enable the study of both heat and charge transport in molecular junctions will be developed in the proposed research program. Using this technique, experiments will be conducted on a variety of single molecule and multiple molecule junctions to elucidate, for the first time, the relationship between structure of the molecular junctions and its thermal conductance. Further, the effect of structure on the electrical conductance and thermopower of molecular junctions will be explored.
Broader Impacts: This program includes the exploration of thermal transport in nanometer-sized molecular junctions potentially leading to the creation a new research area. The proposed work may impact the field of energy conversion; once the dependence of transport properties on structure is understood, it may be possible to tune the heat and charge transport in molecular junctions to create inexpensive and efficient thermoelectric materials using metal-molecule heterostructures. The educational and outreach activities of the proposed program will target students from diverse backgrounds at various educational levels. Underrepresented students from the African-American and Latino communities in the Ypsilanti public school district will be encouraged to study science and engineering by using educational modules designed to illustrate the exciting possibilities of nanoscience. As part of this program, a new two-semester graduate sequence will be introduced to teach engineers advanced concepts from quantum mechanics, solid-state physics, and statistical mechanics. This will enable them to pursue research in a variety of multi-disciplinary areas to solve important problems like renewable energy generation and efficient energy conversion and storage. This course will also be made available to the national and international community by collaborating with the NSF supported Nanohub, an online repository of coursework materials.
