On August 10, 1839, the eminent Russian physicist Aleksandr Grigorievich Stoletov is born (August 10, 1839-May 27, 1896).  Stoletov built the first solar cell based on the outer photoelectric effect (discovered by Heinrich Hertz in 1887).

Born to the family of merchants in 1839, Alexander’s early life was one of study. He learned to read by the time he was four.  Between 1849 and 1860 Stoletov studied physics and mathematics at Moscow State University, where he would become a teacher in 1865.  As a professor worked to establish a physics laboratory for the school (which opened in 1872), so students would not have to go abroad to preform research. By his mid life, Stoletov was a world renown physicist, having developed a theory of “electro-techniques” and discovered important patterns in the magnetism of iron.

In 1888, he turned his attention to the photo effect, which was discovered by Hertz the year before.  He built the first solar cell based on Hertz’s theory and earlier solar technology developed by Charles Fritts in 1883.  Stoletov’s cell was more stable and reliable than the highly inefficient Fritts model.  But it was not until Russell Ohl patented the idea of the junction semiconductor solar cell in 1946, that the modern day solar panel was born.

Additional Stoletov contributions to solar energy also includes the fact that solar cells decrease in efficiency as they age and the direct proportional link between the intensity of electromagnetic radiation acting on a metallic surface and the photocurrent induced by this radiation.  This became known as Stoletov’s Law.