Einstein: The Father of Photovoltaics — Part 2

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This seventh entry in our CleanTechnica miniseries, celebrating the UN’s 2015 Year of Light is focused on Einstein & photovoltaics discovered. Here, physicist John Perlin, author of Let It Shine: The 6000-Year Story of Solar Energy, articulates further why he feels Albert Einstein is the father of modern photovoltaics. Perlin’s expertise on solar energy is considerable.

Let It Shine is the only book that has thoroughly chronicled the development and application of solar throughout time, focusing on key themes, people, and events that have laid the foundation for an enduring Solar Age.


In the last episode, Mr. Perlin pointed out that after the Compton Experiment, the reality of Einstein’s photon and the photovoltaic effect gained universal acceptance in the scientific community. For those who may have missed an episode in this miniseries, here is what has been published:

  1. “Author John Perlin Celebrates the Coming Year of Light”
  2. “Author John Perlin & the Solar Cell”
  3. “The Pathway to Today’s Solar Revolution: Discovering the Photosensitivity of Selenium”
  4. “Photovoltaics Discovered in 1875: Interview with Author John Perlin”
  5. “Photovoltaic Dreaming: First Attempts at Commercializing PV”
  6. “Einstein: The Father of Photovoltaics -Part 1 

We continue here with more on Einstein and his influence on the development of photovoltaics.

CleanTechnica: Please refresh our many non-physicists about the Compton Experiment and the photon.

Perlin: Einstein’s discovery of the photon set the stage for an entire new approach to physics – quantum mechanics – which has come to dominate that field of study. It has completely changed our view of light: that light waves emit energized particles that power solar devices like photovoltaics and why in the absence of light they do not function. Einstein’s light particle theory also introduced the first of many quantum paradoxes – the duality of light as a wave and a particle. No wonder the leading scientific biographer of Einstein cites his light-quanta equation as “as the most revolutionary contribution he ever made to physics.”

CleanTechnica: How would Dr. Einstein regard the contemporary solar panel?

Perlin: He would regard the modern solar panel as one more example of the usefulness of the quantization of light, as it shows the designer how to maximize the collection of photons and therefore performance.

But Einstein’s contribution to solar does not end with the introduction of the photon. His famous equation, E=mc2 , usually associated with the atomic and hydrogen weapons, provides a modern understanding of how the sun produces photons that fuel solar cells.

This equation led the great astronomer Sir Arthur Eddington in 1920 to conjecture that the sun generated its awesome amount of energy by fusing hydrogen into helium. In the process a certain quantity of mass disappears. E=mc2 accounts for the loss by its conversion into energy – just 1 gram lost in this fashion generates 25 million kilowatt hours!

CleanTechnica: Let us simplify these volumes for laypeople that want to heat their home or operate a refrigerator.

Perlin: E=mc2 tells us that the sun will last tens of billions of years. Therefore, no one has to worry about running out of photons. It also informs us that the amount of photons pouring down on us is tens of thousands times greater than the energy that we are now using from fossil fuels

CleanTechnica: Can you elaborate in more detail on Sir Arthur Eddington and reactions among scientists?

Perlin: Eddington’s speculations, and the scientific validation of Einstein’s light quanta, commonly known as the photon by 1924, which in the words of distinguished physicist Arnold Sommerfeld, “created a sensation among the physicists of that time,” inspired great scientific interest in photovoltaics. The pioneering astrophysicist Edward Pettit, for example, writing in a 1930 issue of Popular Mechanics called photovoltaics, “The Power of the Future,” adding, “Sooner or later we shall have to go directly to the sun for our major supply of power.”

CleanTechnica: So, once again, scientists dreamed of the promise of photovoltaics?

Perlin: Yes. In 1931, in fact, Popular Mechanics featured solar cells built by German scientist Bruno Lange. Speaking about his solar plates, he predicted, “in the not-to-distant future, huge plants will employ thousands of these plates to transform sunlight into electric power … with hydroelectric and steam-driven generators in running factories and lighting homes.

CleanTechnica: Were these plates more effective than the ones Fritts had designed years earlier?

Perlin: No. Lange’s solar cells worked no better than Fritts’, converting less than 1% of all incoming light into electricity – hardly enough to justify its consideration as a source of power.

Others tried different materials than selenium, such as cuprous oxide, though none could better selenium. With no breakthroughs on the horizon, Vladimir Zworykin and Edward Samberg concluded pessimistically in their authoritative book, Photoelectricity and Its Applications, published in 1949, “It must be let to the future whether the discovery of more efficient solar cells will reopen the possibility of harnessing solar energy for useful purposes.”

Coming next: The discovery of a more efficient solar cell that reopened the possibility of harnessing solar energy for useful purposes.

Photo Credit: Concept of a businessman that solves problems of Albert Einstein via Shutterstock 

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Glenn Meyers

is a writer, producer, and director. Meyers was editor and site director of Green Building Elements, a contributing writer for CleanTechnica, and is founder of Green Streets MediaTrain, a communications connection and eLearning hub. As an independent producer, he's been involved in the development, production and distribution of television and distance learning programs for both the education industry and corporate sector. He also is an avid gardener and loves sustainable innovation.

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