New transparent solar cell technology to revolutionise electricity generation

The Incheon National University in Korea has developed a fully transparent solar cell. The breakthrough technology is set to revolutionise electricity generation with the possibility for the technology to be integrated to windows, buildings, or even mobile phone screens in the future.

The technology was revealed in a new study in Journal of Power Sources, an international team of researchers, led by Prof. Joondong Kim from Korea.

The unique features of transparent photovoltaic cells could have various applications in human technology

Prof. Joondong Kim

Over the past decade solar cells have become cheaper, more efficient, and environmentally friendly. However, current solar cells tend to be opaque, which prevents their wider use and integration into everyday materials, constrained to being lined up on roofs and in remote solar farms.

The South Korean researchers, who detailed their findings in a study, devised a cell composed of a glass substrate and a metal oxide electrode, on top of which they deposited thin layers of the two semiconductors one after the other and added a final coating of silver nanowires to act as the other electrode.

The idea of transparent solar cells is well known, but this novel application where scientists have been able to translate this idea into practice is a crucial new finding. At present, the materials making the solar cell opaque are the semiconductor layers, those responsible for capturing light and translating it into an electrical current. Hence, Prof. Kim and his colleagues looked at two potential semiconductor materials, identified by previous researchers for their desirable properties.

The first is titanium dioxide (TiO2), a well-known semiconductor already widely used to make solar cells. On top of its excellent electrical properties, TiO2 is also an environment-friendly and non-toxic material. This material absorbs UV light (a part of the light spectrum invisible to the naked eye) while letting through most of the visible light range. The second material investigated to make this junction was nickel oxide (NiO), another semiconductor known to have high optical transparency. As nickel is one of the most abundant elements on Earth, and its oxide can easily be manufactured at low industrial temperatures, NiO is also a great material to make eco-friendly cells.