Abstract: The ability to render semiconductors into inks and to print them with bespoke properties promises the herald of next-generation low-cost printed semiconductor electronics for terrestrial and space applications. While several semiconductor inks have emerged including metal oxides, colloidal quantum dots, perovskites, polymers, and 2D materials, ink printing lacks the pristine quality achievable by conventional time-consuming and unscalable single crystal growth platforms that enable defect-free forms of matter. As the ink building blocks come closer and pack during thin-film formation, interfacial and microstructural complexity increases. The challenge is to achieve controlled film fabrication, crystallization, and packing of matter at high speed. Developing diagnostics that can provide insights into printed film quality is a first step toward addressing this challenge. I will talk about my research efforts that have drawn attention to the interfacial and microstructural complexity in printed electronics and the need to understand it to drive the lab-to-fab transition. I will elaborate on the key highlight of my prior research: high-speed coating of colloidal quantum dot optoelectronics and metal-oxide thin-film transistors. Design of these high-quality printed electronic devices was informed by insights gleaned from surface-sensitive photoemission spectroscopy and synchrotron-based X-ray scattering tools. Understanding of the electronic band structure and defect physics, and control over crystallographic texture will be highlighted as key enablers of new device design rules. I will close with an introduction to my proposed research program at the Colorado School of Mines which will establish quality control in printed electronics by combining interfacial and microstructural diagnostics. These insights will be used to develop ultra-thin oxide electronics, radiation-hard electronics for space, and recycled perovskite photovoltaics for circular economy. A consensus article on radiation-testing of perovskite semiconductors based on my ongoing NREL research work will lay the foundation of space-relevant research direction in my program.
Figure. Research vision of the proposed Kirmani laboratory.
Biography: Ahmad Kirmani is a postdoctoral researcher in the group of Dr. Joseph Luther at the National Renewable Energy Laboratory (NREL), CO, where he is leading a DOD-funded research thrust to explore solution-processed perovskite solar cells for space applications. Ahmad has a Ph.D. degree (2017) in materials science from the King Abdullah University of Science & Technology (KAUST) under the supervision of Prof. Aram Amassian (now, North Carolina State University) where he explored surface structure-property correlations in colloidal quantum dot photovoltaics. Prior to joining NREL, he was a guest researcher at the National Institute of Standards and Technology (NIST) working with Dr. Lee Richter and Dr. Dean DeLongchamp. While at NIST, he researched scalable coating of metal-oxide inks and colloidal quantum dot self-assembly using synchrotron X-ray scattering. His research interests include roll-to-roll compatible coating and characterization of inorganic semiconductor inks, such as colloidal quantum dots, perovskites, and metal oxides. Ahmad has published over 40 journal articles including first-authored papers in high-impact journals such as Joule, Advanced Materials, and ACS Energy Letters. He is also a volunteer science writer for the Materials Research Society (MRS) and has contributed 10 news articles, opinions, and perspectives.
Personal Website: www.ahmadrkirmani.com, Twitter: @AhmadRKirmani
Lecture held in CoorsTek room 282