Experienced Solar Executives

Leading the next generation of solar technology innovation.

Scott Graybeal CEO
Scott Graybeal


Scott Graybeal is a veteran executive who led the Energy Solutions Segment at Flex Ltd (NASDAQ: FLEX), a $2B division within the company serving the solar, energy storage, and LED lighting markets. Under his leadership, Flex Energy became the third largest producer of PV modules outside of mainland China, and patented several key solar manufacturing innovations. Scott’s career spans several industries from construction tech to solar to semiconductors. Before joining Caelux, Scott was COO of Veev Group & CEO of Veev Build and has held key leadership roles at Intevac, Amonix, Oerlikon Solar, Veeco Instruments, Applied Materials, and General Electric.

Scott has guest lectured on renewables and entrepreneurship at Carnegie Mellon and Georgetown. He served with distinction as a nuclear submarine officer and is a certified nuclear engineering officer by the Departments of the Navy and Energy. Scott earned his MBA from Thunderbird School of Global Management and his BS in Chemistry from UC San Diego.

John Iannelli President & Founder
John Iannelli

President & Founder

John Iannelli is an experienced technology executive who started Caelux in 2014 with the goal of improving the performance of crystalline silicon modules using nanomaterials. Prior to founding Caelux, he worked in venture capital at Khosla Ventures focusing on investments in renewable energy generation and storage, smart grid, and solid-state lighting. He has served as the Corporate Chief Technology Officer and Solar General Manager at Emcore Corporation, and began his career as a Research Scientist, and later Engineering Director at Ortel Corporation, Agere Systems, and Lucent Technologies.

John has served as a visiting faculty member at Caltech and has authored numerous scientific research papers, patents, and industry review articles on semiconductor device physics, laser and optical technologies, and solar energy. John received his PhD from the California Institute of Technology, his MBA from USC’s Marshall School of Business and his BS from Rensselaer Polytechnic Institute.

Charlie Hasselbrink CTO
Charlie Hasselbrink


Ernest “Charlie” Hasselbrink led Global Quality, Reliability R&D, and Performance R&D during his 9 years at Sunpower (now Maxeon Solar). His Reliability R&D team invented several methods to speed R&D cycles of learning, including a patented method to accelerate UV testing by a factor of 100,000. He and his team compiled the technical due diligence for the sale of the largest single permitted solar power plant site in the United States at the time, to Berkshire Hathaway Energy. A champion for reliability in the PV industry, he was a plenary speaker for Reliability at the IEEE 39th PV Specialists Conference (PVSC) and was Area Chair for Reliability for PVSC 42.

Charlie’s career includes roles as VP Reliability and Quality at Mainspring Energy, and VP of Front-End Technology Development at Sila Nanotechnologies. Charlie has been a tenure-track professor of mechanical engineering at the University of Michigan (Ann Arbor) and a post-doctoral researcher at Sandia National Labs. He earned his Ph.D. from Stanford University and his B.S. in Mechanical Engineering from the University of Houston. His 50 journal papers, conference papers and patents have been cited >4000 times.

Jeremy Ferrell CFO
Jeremy Ferrell


Jeremy Ferrell has more than 25 years of finance and operations leadership experience, with expertise in venture capital; mergers and acquisitions; due diligence; initial public offerings; strategic alliance negotiation; and financial planning and reporting. He was most recently CFO at Miku, Inc, a privately held consumer hardware and tele-health company, where he managed a successful seed financing round and led Miku’s transition from its parent to an independent company. Previously, he founded a Fractional CFO Services firm, where he served as CFO for various life sciences and technology companies, including Singular Genomics, Inc., Aspen Neuroscience, Inc., and Hyduro, Inc.

Mr. Ferrell received his Bachelor of Science degree in Accountancy from Liberty University and his Master of Business Administration degree in International Finance from the Thunderbird School of Global Management.