• MIT professor and solar innovation leader, Tonio Buonassisi, to take over as VP of Sustainable Energy at CSEM on January 1, 2026.
• Appointment strengthens CSEM’s mission to accelerate technology transfer and impact.
• Professor Christophe Ballif remains on board as Scientific Advisor after over a decade of groundbreaking leadership.

CSEM announces the appointment of Professor Tonio Buonassisi as its new Vice President of Sustainable Energy, with the official handover set for January 1, 2026. A renowned expert in photovoltaics and AI-driven energy innovation, Buonassisi will join CSEM later this year. He succeeds Professor Christophe Ballif, who will continue to contribute to CSEM as Scientific Advisor after leading its sustainable energy activities since 2013.

A global leader in energy innovation

Professor Tonio Buonassisi joins CSEM with a remarkable international track record in photovoltaic innovation, AI-driven materials discovery, and sustainable technology development. As a Professor of Mechanical Engineering at Massachusetts Institute of Technology (MIT), he is renowned for pioneering the application of artificial intelligence in the development of next-generation energy materials. His work has catalyzed innovation across academia and industry, earning him accolades including the Presidential Early Career Award for Scientists and Engineers (PECASE) and the NSF CAREER Award.

Tonio Buonassisi brings a deep commitment to both innovation and impact. His technoeconomic analyses have helped companies shape strategic R&D efforts, and his work integrating photovoltaics into emerging applications from off-grid desalination to IoT has global significance. Tonio Buonassisi recently served as founding director of ADDEPT, a U.S. Department of Energy initiative aimed at developing durable perovskite-silicon tandem modules.

“Tonio’s expertise in AI and photovoltaics will build on the exceptional foundation laid by Christophe Ballif whose visionary leadership has shaped CSEM’s global impact. This transition strengthens our commitment to driving sustainable innovation“ says Alexandre Pauchard, CEO at CSEM.

“I’m excited to join the exceptional team at CSEM to innovate with our partners toward a more sustainable future, building on the Swiss ecosystem’s strengths in automation, digital technologies, and resource-efficient manufacturing.” says Buonassisi.

A tribute to Christophe Ballif

This leadership transition also offers an opportunity to honor the exceptional contributions of Christophe Ballif, who has been at the helm of CSEM’s Sustainable Energy activities since 2013. He founded and established the PV division as a combined unit of EPFL’s PV Lab and CSEM’s activities. Under his direction, the group grew to over 90 researchers and played a central role in the industrialization of advanced photovoltaic technologies, energy storage systems, and digital energy solutions, in collaboration with over 40 industry partners.

From the launch of the pilot line for heterojunction solar cells, to record-breaking tandem perovskite-silicon efficiency, Christophe Ballif has driven technological breakthroughs that helped shape the solar energy landscape in Switzerland and beyond. His leadership enabled key innovations such as colored PV modules, ultra-light solar cells for stratospheric flights, solar-powered connected watches (Tissot), and historic-building-compatible PV tiles. His work earned him the Becquerel Prize in 2016, and he remains a key member of Switzerland’s scientific and energy policy landscape.

With this handover, CSEM continues to affirm its role as a bridge between cutting-edge research and industrial application, ensuring continuity, excellence, and global relevance in sustainable energy innovation.