This award supports theoretical and computational research and education to model the interaction of light with particular materials. The research will focus on understanding electronic properties and charge-transfer mechanisms in disordered systems which has impact on efforts to develop improved photovoltaic and photocatalytic materials, and better light-sensing devices. Scientific goals are to determine: 1) The structure of ordered and disordered photoactive oxides including vanadium and titanium based oxides, 2) The atomistic origin of light induced effects in these oxide systems as well as in glasses, for example the Staebler-Wronski effect in hydrogenated amorphous silicon and analogous phenomena in chalcogenide glasses, 3) Fundamental understanding of charge and energy transfer processes in acceptor-donor biomolecules with a focus on chlorophyll-carotene systems for potential bio-inspired photovoltaics, 4) Fundamental understanding of charge transfer processes in photoactive metal organic framework materials. Practical new codes will be developed for non-adiabatic molecular-dynamics simulation. The research will be carried out in collaboration with experimental groups with an aim to guide experimental research. Collaborations with other theoretical groups will enable powerful computational techniques to be developed.
The PIs will leverage several student research programs already in place in the State of West Virginia; these programs extend to Drabold through Lewis and thus will impact Ohio University students as well. The PIs will recruit students from these programs and are committed to a mission of broadening participation in their computational materials research. Developing a strong program in nanoscale science and engineering, including developing cyberinfrastructure capabilities, is also a priority for the State of West Virginia. The PIs will further extend and develop a strong program of science outreach to K-12 students and teachers in Appalachia. The PI?s will start a pilot annual joint scientific conference entirely for, and to the maximum degree possible, administered by regional students. The efficacy of this work will be quantitatively gauged and reported.
NONTECHNICAL SUMMARY This award supports theoretical and computational research and education to use advanced computational methods to study how light interacts with several classes of technologically important materials, focusing on the motion of electronic charge induced by exposure to light. Technological applications of these materials include generation of energy from sunlight and catalyzing chemical reactions like the transformation of carbon dioxide into methanol induced by light. The research will focus on understanding key quantum mechanical states of electrons that are important when the material is exposed to light and how electronic charge moves from one group of atoms to another.
This is fundamental research that contributes to the intellectual foundations of solar energy generation and photochemistry. The research will be carried out in collaboration with experimental groups with an aim to guide experimental research. Collaborations with other theoretical groups will enable powerful computational techniques to be developed.
The PIs will leverage several student research programs already in place in the State of West Virginia; these programs extend to Drabold through Lewis and thus will impact Ohio University students as well. The PIs will recruit students from these programs and are committed to a mission of broadening participation in their computational materials research. Developing a strong program in nanoscale science and engineering, including developing cyberinfrastructure capabilities, is also a priority for the State of West Virginia. The PIs will further extend and develop a strong program of science outreach to K-12 students and teachers in Appalachia. The PI?s will start a pilot annual joint scientific conference entirely for, and to the maximum degree possible, administered by regional students. The efficacy of this work will be quantitatively gauged and reported.
This award highlighted the electronic structure of complex materials and the network structure of glasses and non-crystalline materials. The first models of the key photocatalyst amorphous TiO2 were created, and a specific exciting prediction was made for the light emitting diode material amorphous GaN, sugesting its utility as an important electronic material. We showed that phase change memory materials, now being widely adopted in cell phones, are substantially improved by the addition of silver and detail the reasons why. A patent application is under review. We developed a new theory of transport in complex systems more complete than conventional methods. We carried out some of the first calculations on amorphous graphene and were the first to prove that the sheet puckers (a flat sheet is unstable). We also explained, in atomistic detail, why the key photovoltaic material hydrogenated amorphous silicon is so difficult to dope (that is, add impurities to make the material electrically useful). I co-organized two international workshops in Cambridge, England on Disordered Materials and in Arizona on biomolecular systems and other complex materials. I was primary Editor for Proceedings for each meeting. I graduated three PhDs during the period of the award, and contributed significantly to outreach activities to the community with the Open House at OU. My graduating students from this period have done well. One is a professor in Pakistan, one a post doc, and one is medical resident in medical physics at Washington University in St Louis. The most recent graduate, Binay Prasai, is Drabold's 14th PhD. Prasai was an interesting case, as Drabold and Ohio experimentalust Gang Chen jointly supervised him. This unusual arrangement worked extremely well for Prasai. This was motivated in part by the NSF emphasis on close experimental-theoretical collaboration. Our work was disseminated in a large number of invited talks at meetings, colloquium invitations and publications. Our work was highlighted on the cover of Physica Status Solidi four times, and one paper was an Editors Choice with a special commentary in Physical Review Letters.
