Developing high-capacity solar cells

The new cells have an efficiency of 15% to be on par with their traditional counterparts, at a lower cost, and can generate power from clothes and transparent windows.

Developing solar cells with high competitive advantages and capabilities

A difficult equation that an American team succeeded in achieving, which leads to one day finding that our clothes, transparent windows, or even walls of our homes produce solar energy.

And researchers in the departments of electrical engineering and computer science at the University of Michigan announced that they were able to develop flexible organic solar cells that may fit clothes, and can be transparent and placed in windows, to produce solar energy, instead of the traditional solid cells made of silicon.

The research, published in the journal Nature Energy, showed that organic solar cells use carbon in their structure, giving them many advantages over traditional "inorganic" cells. Inorganic silicon solar panels are expensive because they are made of thick, bulky, and rigid panels that require fixed mounting points.

But the low cost carbon-based organic solar cells can be folded; It can be made in the form of thin rolls that can be bent and bend, and integrated around the structures or inside the clothes, and colored or even made transparent, to be part of our surrounding environment, and meet all tastes.

Regarding their production capacity, the researchers explained that the new cells achieved an efficiency of 15%.

With a life expectancy of 20 years, researchers expect that new organic solar cells can produce electricity at a cost of less than 7 cents per kilowatt-hour, and the average cost of electricity production in the United States is 10.5 cents per kilowatt-hour (a unit for energy expression ) In 2017, according to the U.S. Energy Information Administration.

According to the research team, the new cells can reduce the overall cost of a solar energy system, making it a clean energy source everywhere.

The incorporation of these cells into heavy-duty devices such as phones and watches, as well as walls and windows, would revolutionize global energy generation, reduce pollution rates, and mitigate climate change as well.

Cell efficiency

Despite these advantages, these cells lacked the efficiency required to compete with traditional energy sources.

Regarding the rate of improvement made by the scientific team in the new cells, Xiao Zhao, the leader of the research team, said, "Over the past two years, the efficiency of organic photovoltaic cells has been stuck between 11 and 12%."

In an interview with "For Science", he added that to develop the efficiency of these cells, the team has made several additions to the design; They designed a system that combines specialized layers to absorb visible and infrared light, and they focused mainly on two organic solar cells, one capable of absorbing light from the visible spectrum starting at 350 nanometers in wavelength, and another capable of absorbing near infrared rays of up to 950 nanometers in wavelength (different solar radiation can be distinguished by its wavelengths, which are measured in nanometers, equal to one millionth of a millimeter).

"The cells achieve an efficiency of 10-11%, and when we put them together, we increase the light absorption and improve the efficiency to 15% with an anti-reflective coating," Chi added.

To combine the two cells, the team developed overlapping layers that prevent damage to the first cell, and allow light and electricity charges to pass through. "It is a difficult process because there is a possibility that the liquid used to treat the upper cell dissolves the layers underneath," Chi said.

Regarding their future aspirations for the efficiency of organic cells, Zhao predicted that "the team can improve the light absorption process to increase the electric current, and reduce the energy loss to increase the voltage, and based on calculations, the efficiency in the near future of these cells is expected to reach 18%."

Small applications

"Amin Mubarak" - a professor of mechanical energy at the Faculty of Engineering, Cairo University - said that the production of these organic cells from electrical energy is equivalent to the production of traditional solar panels, whose efficiency reaches 15%, and this means that if 1000 kilowatts of sunlight per hour falls on them, It produces 150 kWh.

But he saw - in an interview with "science" - that these cells are still in the process of experiment, and they need about 5 to 10 years of production on the commercial and investment levels to evaluate their efficiency and production rates.

He added that scientists also need to monitor the erosion factors that these cells are exposed to, as traditional cells have been tried for a long time and have proven efficient under erosion factors such as different temperatures and cold, rain, dust and air, and despite this, their efficiency decreases over time by about 1 % Approximately every two years, which we need to measure in new cells.

He emphasized that the flexibility advantage granted by organic solar cells is useful in small applications and industries that traditional solar cells cannot adapt to, such as houses with circular dome, transparent clothes and windows, etc., but the traditional cells remain more suitable in the case of building solar cell farms in the desert. Until those organic cells prove their efficiency.