A new study led by scientists at Korea’s Incheon National University demonstrates how to create a solar cell that is fully transparent.
The first transparent solar cell was demonstrated by an international team of researchers led by Prof. Joondong Kim of Korea in a new report in the Journal of Power Sources.
Their groundbreaking technique relies on a particular part of the solar cell: the heterojunction, consisting of thin layers of light-absorbing materials.
The researchers were able to build an effective, transparent solar cell by combining the unique properties of titanium dioxide and nickel oxide semiconductors.
Five years after the Paris Climate Agreement, all eyes are on the development of the planet towards a future that is carbon-free.
The energy transition from fossil fuels to renewable sources such as solar, hydro, wind and wave energy is a vital part of that goal.
Among these, since it is the most efficient and plentiful source of energy on Earth, solar energy has always held the highest expectations in the scientific community.
Solar cells have become cheaper, more efficient, and more environmentally friendly in recent decades. Current solar cells, however, are typically opaque, preventing their broader use and incorporation into everyday materials, restricting them to being strung on rooftops and in remote solar farms.
But what if it is possible to incorporate the next generation of solar cells into walls, buildings or even mobile phone screens? That’s the dream of Professor Joondong Kim of the Incheon National University Department of Electrical Engineering, Korea.
He and his colleagues identified their new discovery in a recent study published in the Journal of Power Sources: a fully transparent solar cell. “The unique properties of transparent photovoltaic cells could have various applications in human technology,” Prof. Kim says.
The idea of transparent solar cells is well known, but a key new development is this innovative application in which scientists have been able to bring the idea into effect.
At present, the semiconductor layers responsible for absorbing light and turning it into electricity are the materials that make solar cells opaque. Therefore, two possible semiconductor materials identified by previous researchers for their desirable properties were investigated by Prof. Kim and his colleagues.
Titanium dioxide (TiO2), a well-known semiconductor that is already widely used for solar cell processing, is the first. TiO2 is also an environmentally friendly and nontoxic material, in addition to its excellent electrical properties.
UV light (a part of the light spectrum that is invisible to the naked eye) is absorbed by this substance when transmitting much of the visible light range.
Nickel oxide (NiO), another semiconductor noted for its high optical clarity, was the second material studied for making the junction.
Since nickel is one of the most abundant components on Earth and it is simple to manufacture its oxide at low industrial temperatures, NiO is also a great material for producing cells that are environmentally friendly.
Reference:’ TiO2/NiO heterojunction transparent photovoltaic cells and self-powered photodetectors’ by Thanh Tai Nguyen, Malkeshkumar Patel, Sangho Kim, Rameez Ahmad Mir, Junsin Yi, Vinh-Ai Dao and Joondong Kim, Journal of Power Sources, 12 September 2020. DOI: 10.1016/j.jpowsour.2020.2288655.