Timothy Gessert is the Principal and Managing Member of Gessert Consulting, LLC, and Adjunct Professor at University of Illinois at Chicago. Tim is also a retired Principal Scientist, formerly at the National Renewable Energy Laboratory (NREL) in Golden, Colorado. He received degrees in physics from University of Wisconsin-River Falls (B.Sc.), Colorado School of Mines (M.Sc.), and University of Wales - College of Cardiff (Ph.D). His 30+ years of research at NREL included leading the Device Development and Fabrication Team, and the Thin-Film Photovoltaic Devices Research Group. Research activities have included develop­ment of vacuum and photolithographic processes, transparent-conducting oxides, photovoltaic absorber layers, and related electrical contacts. His present research is directed at understanding how choices in processes and device design affect the ultimate performance, stability, and other application aspects of polycrystalline and crystalline photovoltaic devices. Tim has more than 240 publications, more than 10 issued US Patents, and has authored two books on vacuum technology. Tim is a Fel­low and former President of the American Vacuum Society, and serves as Editor-in- Chief for the journal Thin Solid Films. He is also co-author, along with John O’Hanlon, of “A Users Guide to Vacuum Technology”, 4th Edition, John Wiley and Sons, 2023.