In Memoriam Klaus Thiessen
Optoelectronics specialist and solar energy pioneer
Professor Klaus Thiessen passed away on 3 July 2025 at the age of nearly 98. The internationally recognised expert in optoelectronics remained a committed bridge-builder between science, industry, and society well into his later years. He dedicated himself with great passion to solar energy, earning the internationally acclaimed reputation of being the “solar pope of Adlershof”.
Born in 1927, the son of physical chemist Peter Adolf Thiessen, he went to the Soviet Union after 1945, where he studied physics and earned his doctorate. Upon returning in 1958, he worked at the Physikalisch-Technisches Institut of the Academy of Sciences (AdW) in Adlershof. He later conducted research in industry before returning to Adlershof in 1981.
After German reunification, Thiessen formally retired in 1992, but he never stepped away from his work. He had begun exploring photovoltaic technology as early as the 1960s. “Back then it was purely fundamental research,” he once said, noting that the challenge now “was to prove that photovoltaics is not a gimmick, but can contribute to reducing fossil fuel consumption.” Thanks to his initiative and with the support of WISTA Management GmbH, 34 photovoltaic systems were installed in Adlershof by 2012, with a combined capacity of nearly 1.9 kWp (kilowatt-peak).
Dr. Peter Strunk for Adlershof Journal