The first affordable solar panels made from synthetic materials will be available on the market within the next five years. This is the latest announcement from scientists who are increasingly competing in this field. 
The “golden age” of coal, oil, and gas is gradually coming to an end. Although slow, it is inevitable. Sooner or later, their reserves will be depleted. What will we replace them with? Many researchers believe that solar energy is the resource we must harness to convert into thermal and electrical energy.
This raises an issue, as any household equipped with solar panels knows well how much investment it requires. Why is that? Because traditional solar panels utilize quartz crystals, which are costly to produce. Quartz is created at temperatures around 1500 degrees Celsius in a vacuum, requiring significant energy derived from conventional fuels.
However, quartz is not the only option. There are synthetic materials as well. More specifically, conductive polymers have been known to science for a quarter of a century. In the 1990s, they were used to produce photodiodes. In recent years, scientists have experimented with using synthetic materials to create solar panels. If successful, this would represent a significant breakthrough, a revolution in science, as it would allow us to access the most abundant energy source at a very low cost, with reserves plentiful for billions of years to come.
“Unlike quartz, conductive polymers can be produced at normal temperatures. Moreover, the thin plastic layers are arranged using techniques similar to printing, thus requiring less energy,” explains Professor Adam Pron from the Warsaw University of Technology in Poland, who is currently working at the Atomic Energy Commission in Grenoble, France.
Similar research is currently being conducted at many research centers worldwide, but the level of competition is particularly evident in the United States, where even different research teams within the same university are competing against each other. For instance, at the University of California, Professor Yang Yang’s research team published their findings in the journal “Nature Materials” at the beginning of October, while recently, Professor Paul Alivisatos’ team at Berkeley introduced their latest discoveries in the journal “Science”.
Both team leaders are distinguished scientists. Professor Yang Yang is a protégé of Nobel laureate Alan Heeger, who received the Nobel Prize in Chemistry in 2000 for discovering the unusual properties of conductive polymers, along with two other scientists, Alan MacDiarmid and Hideaki Shirakawa. Alivisatos is a leading expert on nanocrystals, which play a crucial role in absorbing solar energy on Earth.
Professor Malgorzata Zagorska from the Warsaw University of Technology, who is currently researching semiconductor nanocrystals, explains: “Nanocrystals are objects that range in size from one to a few nanometers. Common nanocrystals are spherical. They are incredibly small. If a ping-pong ball is smaller than the Earth by many times, then a spherical nanocrystal is smaller than a ping-pong ball by the same factor.”
In 2002, Alivisatos proposed incorporating semiconductor nanofibers into polymers. He believed this method could enhance the efficiency of solar panels made from synthetic materials. Unfortunately, even the best conductive polymers (such as P3HT) do not effectively separate positive and negative charges. In short, they do not know how to generate electricity from light. Another component, such as nanocrystals, is needed to help the polymer create an electric current.
After Alivisatos decided to embed salen-cadmium nanofibers (a semiconductor similar to silicon) into the synthetic polymer, his initial solar panel achieved an efficiency of 1.7%, meaning that this portion of sunlight was converted into electricity. This is still quite low, less than 10 times the efficiency of an average quartz panel, not to mention the best (and most expensive) panels that reach efficiencies of up to 35%.
However, we should also remember the advantages of using synthetic polymer panels. First, the production cost is very low (as mentioned above). Second, synthetic polymer panels have high compatibility. They are extremely thin—the polymer layer is only a few hundred nanometers thick—and very flexible. Therefore, they can be applied to cover windows, laptop screens, or mobile devices; they could even be sprayed onto clothing to generate electricity from sunlight. If we can increase the efficiency of this synthetic material, we would have a “nearly perpetual engine” at our disposal. The question is, how do we increase it?
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Scientist Alan Heeger |
It was Nobel laureate Alan Heeger, along with his collaborator Serdar Sariciftci, who proposed a new idea—incorporating fullerenes into synthetic materials. Discovered in 1990, fullerenes are carbon molecules made up of multiple atoms, forming various shapes and spatial structures: spherical, helical, and tubular. Fullerene C60 was the first discovered. Its molecule consists of 60 carbon atoms and resembles a ball. Heeger and Sariciftci mixed a derivative of fullerene C60 with synthetic polymer, achieving a solar panel with an efficiency of 2%.
Their method was later refined in the laboratory by Professor Yang Yang, who increased the efficiency of the fullerene polymer panel to 4.4%. He claimed this was the best solar panel in the world and stated that within the next five years, he would raise the panel’s efficiency to 10%. He said, “At that point, we could mass-produce synthetic polymer panels.”
However, Professor Yang Yang was mistaken in believing that the panel he refined was the best. Recently, a team of American scientists from New Mexico State University and Wake Forest University announced that they applied a similar method to that of Professor Yang Yang and produced a panel with an efficiency of 5.2%. This intriguing information was disclosed during a nanotechnology conference in Santa Fe, USA. However, specific details were kept confidential, citing military contracts.
Meanwhile, scientist Alivisatos proposed another surprising approach. He concluded that it is possible to design a solar panel that requires no synthetic materials at all, only selenium-cadmium nanocrystals would suffice. The details of his research were described in a recent issue of “Science”. His solar panel model has an efficiency of about 3%. “This efficiency is still low, but considering it is the first selenium-cadmium solar panel in the world, it is not bad,” he emphasized. “Its advantage is that the efficiency does not decrease over time. This is a problem we have yet to solve with synthetic polymer panels.”
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