The primary goals of this research supported by the Solid State and Materials Chemistry program are to develop the synthetic methodology for creating organic-passivated single atom thick sheets of silicon, evaluate their stability in air and water environments, and study their optical and electronic properties both in the bulk and as single isolated sheets. These organic-terminated silicon sheets will be synthesized by combining nonaqueous deintercalation of layered Zintl silicon phases with surface functionalization processes. A combination of X-ray diffraction, Raman, FTIR, XPS, AFM, SEM, and TEM measurements will be employed to characterize the structure and morphology as well as evaluate the long-term air and water stability of these materials. The optical and electronic properties of these layered silicon graphane analogues will be characterized using absorption, fluorescence, and electronic measurements on bulk pellets and single isolated sheets. These single atom thick silicon graphane analogues are expected to be air- and water-stable, and possess numerous advantages compared to bulk silicon and other two-dimensional layers, including having a direct and tunable band gap, as well as the capability for covalent functionalization with minimal disruption to conductivity, thus potentially making them a versatile building block for a multitude of applications.
The discovery of allotropes of carbon that are zero-dimensional (fullerene), one-dimensional (nanotubes), and two-dimensional (graphene), has opened up entire fields of research and ultimately culminated in two Nobel prizes. Still, silicon remains the most ubiquitous and technologically significant material of our time. This research program focuses on understanding how to synthesize single atom thick sheets of silicon that are protected with organic molecules for air- and water- stability, and evaluationg their optical and electronic properties. Considering the promise and application of silicon in computing, photovoltaics, thermoelectrics, battery electrodes, spintronics, and chemical/ biochemical sensing, the creation of new air- and water-stable allotropes of silicon with fundamentally unique properties can hold great potential in numerous technologies, including renewable energy technologies. This program will be integrated with educational and outreach activities at Ohio State which target high school students, undergraduates, and the general public. The PI is actively involved in mentoring underrepresented groups at both the undergraduate, and graduate levels, encouraging their development as the next generation of materials innovators. Finally, this program will support community outreach activities designed to foster interest in materials- and energy-related science, technology, and engineering at the K-12 level, via collaborative programs with the Center of Science and Industry (COSI) museum, and the state Science Olympiad program.
With support from We have successfully synthesized a new 2D, single atom thick Germanium analogue of graphene, the 2010 Nobel Prize winning material. These materials show significant advantages compared to Silicon and Germanium, including faster electron transport, and enhanced light absorption. In contrast to graphene, we have predicted that these optical and electronic properties can be tuned by changing the terminating substitutent. These materials show incredible promise for applications ranging from solar cells, LEDs, Lasers, thermoelectrics, and transistors. Broader Impacts Broadened Participation of Underrepresented Groups: This work went to directly support the training in my research group of Sheneve Butler, an African-American female graduate student, as well as Elisabeth Bianco, an undergraduate student, in my research group. As a result of this work, Elisabeth won 2nd place in the Spring 2012 Denman Undergraduate Research poster competition at The Ohio State University and won first prize in the Notre Dame Undergraduate Research in Nanoscience 2012 competition. Elisabeth is attending UC Berkeley for Graduate School in the Fall of 2013. Outreach Activities: I wrote the test and helped organize volunteers for the "Forensics" competition for the 2012 state Science Olympiad Tournament. Workshop Organization: I was the principal organizer of a workshop on "2D Materials beyond graphene" that was held August 7th-8th at the Ohio State University.
