In the glorious years at the beginning of the century when the markets exploded, global photovoltaics (PV) conferences exploded as well. Many thousands of people attended with enthusiasm. The difference compared with PV is that the photoelectric effect does not involve the creation of a voltage, only the electric conductivity is altered by the incoming light as a function of its intensity. Yet the Swiss PV company Meyer Burger declared in early 2019 that perovskite is good, in particular its hetero-junctions on silicon crystal cells. The technology is to come from Oxford PV. America was catching up later and was in 2018 well ahead of Germany with respect to PV markets. The original pioneer for its development was the late Dieter Bonnet in Germany. For his achievement, he received a Becquerel award and a street was named after him in his hometown.