As spring arrives in NH and the sun starts to melt all the snow away, we think back to the early tinkerers, artists and scientists who first started trying to harness the energy of the sun.
The names most commonly associated with the discovery of photovoltaics are Alexandre-Edmond Becquerel (pictured) and Albert Einstein, who were both born in the month of March.
Alexandre-Edmond Becquerel (March 24, 1820 - May 11, 1891) first published his observations of the photoelectric effect in 1839 at the age of 19. The simple explanation of the photoelectric effect is that light contains energy, and its energy can be absorbed by charged particles (electrons) in the atoms of solid materials. The energy of the light can cause electrons to be ejected from their atoms, so that they can travel as an electric current in a circuit.
In 1905, Albert Einstein (14 March 1879 – 18 April 1955) published his famous explanation of the photoelectric effect, for which he was awarded the Nobel Prize in 1921. The discovery and explanation of the photoelectric effect set the stage for the development of the photovoltaic industry that we know today. It took a long time before solar materials had a reasonable efficiency of 10% or more and could be considered as a significant source of power.
Between 1839 and 1905, many great minds were focused on questions about the nature of light and the structure of matter. To illustrate just how far we’ve come from then, our present state of understanding compared to our understanding in 1839 is like our present communications technology compared to the cutting edge communications technology of the time – the telegraph.
Although Becquerel is often credited with the “discovery” of the photoelectric effect, in reality many individuals contributed with their own experiments and observations, adding piece by piece to the pile of knowledge until Einstein was finally able to put it all together. We think it’s important to recognize the teamwork that got solar where it is today. Here’s a partial list of some of the most important players – we hope you enjoy!
1873 Willoughby Smith, (1828 —1891) discovered the photoconductivity of selenium while developing a method to test telegraph cable as it was being lain.
1877 William G. Adams (1836-1915) and Richard E. Day (? - ?) observe the photoelectric selenium produces electricity when exposed to light.
1883 American inventor Charles Fritts (1838 – 1905) describes the first solar cells made of selenium wafers.
1887 Heinrich Hertz (1857 – 1894) observes that ultraviolet light affects the voltage of a spark between two metal electrodes.
1888 Edward Weston (1850 – 1936) received the first patent for a device called a “solar cell.”
1899 J.J. Thomson, (1856 – 1940) is credited with discovering the electron, although he called it a "corpuscle".
1904 Wilhelm Hallwachs (1859 - 1922) observes the photoelectric effect in a combination of copper and cuprous oxide.
1902 Philipp von Lenard, (1862 – 1947) observes that the energy of emitted photoelectrons increases as the frequency of the light increases.
1905 Albert Einstein publishes his paper explaining the photoelectric effect.
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