1.3: Some history of the photovoltaic effect*
The photovoltaic effect was discovered by a 19-year old in 1839: Edmund Becquerel experimented in his father's laboratory in Paris
with two silver-coated platinum electrodes immersed in a dilute acid to form a sort of battery. He kept one electrode shaded and put the other
one in sunlight and observed that these two electrodes altered their electric power , . Nowadays, a system of
this sort is called an electrochemical cell.
In 1876, the photovoltaic effect was reported for the first time in a solid: selenium. It was known for some time that selenium changes
its conductivity under illumination. However, it was William G. Adams (who succeeded the famous Maxwell as professor in London) and his
student Richard E. Day who showed for the first time  that electric power is directly produced under illumination.
Figure 1: The original selenium bars used by Adams and Day in the Institution of Engeneering and Technology,
London. Photo courtesy of John Perlin.
Figure 2: The abstract in Becquerel's original publication .
Figure 3: An excert from Adams and Day's publication .