Cheap solar cells are about to be mass produced

The first low-cost solar cells made from synthetic resin will be marketed after 5 years. It is the latest announcement by scientists - who are vying for increasingly fierce in this area.

The " golden age " of coal, oil and gas is gradually passing, although slow but it is inevitable. Sooner or later their reserves will be exhausted. So what to replace them? Many researchers believe that solar energy is something that we must manage to turn into heat and electricity.

Here comes the problem, because any family that equips them with solar cells knows how to invest at a high cost. Why so? Because the traditional batteries for solar energy are quartz crystals that cost them very high. They produce quartz at a temperature of about 1500 degrees Celsius in a vacuum. This requires a lot of energy from traditional fuels.

However quartz is not the only thing. There is also synthetic resin. Rather, conductive polymers, known to science for a quarter of a century. In the 1990s, people used them to produce photodiode diodes. For several years, scientists have tried using synthetic resins to make solar cells. If successful, it is a major turning point, a revolution in science because with very cheap prices we have access to the most popular energy source, but reserves are abundant for billions of years later. .

"Unlike quartz, conductive polymers can be created at normal temperatures. Moreover, thin plastic layers are arranged by techniques similar to printing techniques, so it does not require much energy - Prof. Adam Pron of Warsaw Polytechnic University (Poland), currently working at the Atomic Energy Commission at Grenoble (France) - explains that.

Similar studies are currently being done in many research centers around the world, but the level of competition can be seen clearly in the US, where even different research groups in the same university are jealous. racing together. For example, at the University of California, GS's research team. Yang Yang has just published the research results in the journal " Nature Materials " in early October, recently, GS's research team. Paul Alivisators of Berkeley introduced the latest findings in the " Science " magazine.

Both team leaders are two outstanding scientists. Yang Yang was a student of scientist Alan Heeger, who received the Nobel Prize in 2000 for his discovery of unusual properties of conductive polymers (along with two other scientists, Alan McDiarmlid and Hideaki). Shirakawa). Alivisatos is a leading expert on nanocrystals - crystals that play an important role in absorbing solar energy on the earth.

GS. Malgorzata Zagorska (Warsaw Polytechnic University - Poland), currently studying semiconductor nanocrystals, explains: "Nanocrystals are objects of magnitude from one to several nanometers. Nanocrystals are common. It's very small.It is many times smaller than the ball, the spherical nanocrystals are many times smaller than the ping pong ball.

It was Alivisator in 2002 that proposed semiconductor nanofibers into polymers. He said that this method could increase the efficiency of solar cells made of synthetic resins. Unfortunately, even the best conductive polymers (such as P3HT polymers) do not effectively divide positive charges and negative charges. In short, it doesn't know how to generate electricity from light. There needs to be another thing - such as nanocrystals, to help the polymer create electricity.

After Alivisators decided to embed salen-sandmi nanoparticles (a silicon-like semiconductor) into synthetic resin, his original battery had an efficiency of 1.7%, meaning that much of the light Sunlight changes into electric current. That's still too little, 10 times less than the performance of a medium-sized quartz battery; Not to mention the best (and also the most expensive) batteries with an efficiency of up to 35%.

However, we should also recall the advantages of using synthetic plastic batteries. First, production costs are very cheap (mentioned above). Second: Synthetic plastic batteries are highly compatible. They are very thin - the polymer layer is only a few hundred nanometers thick - at the same time very flexible. So they can be used to cover glass windows, laptop screens or mobile phones; You can even spray a mixture that produces electricity from the sun onto your clothes. If we increase the efficiency of this plastic then we have in hand "the engine is almost permanent". The problem is how to increase?

Scientist ALan Heeger

It was the scientist ALan Heeger - the Nobel laureate, and his colleague Serdar Saricftci, who came up with the new idea - to put fuleren into synthetic resin. Discovered in 1990, fuleren is a carbon molecule made up of many atoms and creates different spatial shapes and structures: spherical, spring-shaped and tubular. The Fuleren C60 was first discovered. Its molecule consists of 60 carbon atoms and looks like a ball. Heeger and Sariciftci mixed the derivative of fuleren C60 with synthetic resin and created a 2% efficient battery.

Their method was later perfected by the scientist Yang Yang in the laboratory. He has improved the performance of plastic fuleren batteries to 4.4%. He also said that this is the best battery in the world and said within the next 5 years will increase the battery's performance to 10%. "At that time, we could mass produce synthetic plastic batteries," he said.

However, GS. Yang Yang was wrong to assume that the battery he completed was the best. Recently, a group of American scientists from New Mexico State University and Wake Forest said that they applied the same method as that of GS. Yang Yang and has produced a battery with an efficiency of 5.2%. This rather interesting information was published in the nanotechnology conference in Santa Fe (USA). However, the specifics are hidden for the reason that this is an army order.

During this time, the Alivisators scientist made another proposal and was quite surprised. He concluded that solar cells could be designed completely without synthetic resins, only selenium-cadmium nanocrystals are enough. The details of the research have been described in the recent issue of "Science". His solar cell model has about 3% efficiency. "This performance is still small, but in terms of solar cells, the world's first sandy selenium is not so bad," he stressed. "The advantage is that efficiency does not decrease over time. This is problems that we have not yet solved for synthetic plastic battery cases ".

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