Aleksandr Stoletov

Aleksandr Grigoryevich Stoletov was a Russian physicist, born August 10, 1839 in Vladimir and died May 27, 1896 in Moscow, whose research on the photoelectric effect helped found solar cell technology. Educated at Moscow State University, he defended his doctoral dissertation in 1872 and became a professor there the following year, representing Russia at the first World Congress of Electricity in Paris in 1881. Following Heinrich Hertz's 1887 discovery of the photoelectric effect, Stoletov published six papers between 1888 and 1890 establishing what became known as Stoletov's law, the direct proportionality between the intensity of light striking a surface and the electric current it produces, and in the course of this work he built the first solar cell based on that outer photoelectric effect. He also discovered that such cells lose sensitivity over time, a phenomenon called solar cell fatigue, and separately did influential work on ferromagnetism, mapping the relationship between magnetic field strength and permeability in what is now called the Stoletov curve.