[Feb. 20, 2023: Public Relations, Tohoku University]
The researchers coated various thin metals on the ITO and inserted a thin layer of tungsten oxide between the coated ITO and the tungsten disulfide. (CREDIT: luchschenF)
Solar panels often get a bad rap because they spoil the look of homes and businesses. Yet that could be about to change.
Transparent solar cells (TSC) have attracted considerable attention because they can overcome the limitations of traditional non-transparent solar cells1which can convert various components, such as architectural windows, agricultural sheds, smart device glass panels, and even human skin into energy harvesting devices.
A research group has fabricated a highly transparent solar cell with 2D atomic foil. These nearly invisible solar cells have achieved an average visible transparency of 79%, which means they can, in theory, be placed anywhere: the windows of buildings, the front panel of cars and even human skin.
Scientists have long sought to develop transparent solar cells, but the appropriate materials did not exist until now.
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To fabricate the solar cell, the team controlled the contact barriers between indium tin oxide (ITO), one of the most widely used transparent conductive oxides, and a single-layer tungsten disulfide.
They coated various thin metals on the ITO and inserted a thin layer of tungsten oxide between the coated ITO and the tungsten disulfide.
“The way we formed the solar cell resulted in more than 1000 times higher power conversion efficiency than a device using a normal ITO electrode,” said Toshiaki Kato, corresponding author of the paper and associate professor. at the Graduate School of Engineering of Tohoku University. .
Transparent solar cells (TSC) have attracted considerable attention because they can overcome the limitations of traditional non-transparent solar cells,” says Tohoku.

Highly transparent solar cell with 2D atomic foil successfully fabricated. (CREDIT: Toshiaki Kato)
The group’s efforts did not stop there. They also explored how their solar cell can be extended for use in an actual solar panel.
“It was found that the aspect ratio […] [of the] the device must be below the critical value of approximately 36,” the document explains.

(a) Schematic illustration of the structure of the device and the ideal optimal band structure for the transparent Schottky solar cell. (b) Images of samples for WF and AVT measurement. The ITO was sprayed onto a quartz substrate and a thin metallic film was applied on top of the ITO. (c) Transparency spectra of quartz, ITO/quartz and Mx/ITO on quartz (Mx = Ni1, Ni5, Fe1, Fe2, Al1, Al5, Cu1, Ag1, Au1 and Au5). (d) Plot of WF for Mx/ITO measured by PYS. The inset in (d) shows the typical photoemission characteristics of Ni1/ITO and the fitting curve to obtain the WF. (e) Transparency scatters and working function of Mx/ITO tested. (CREDIT: Scientific Reports)
“By further increasing the size of the device considering an optimal series-parallel connection structure, an extremely high transparency of 79% could be achieved, with PT reaching up to 420 pW. [picowatts].”
“We discovered the appropriate design changes needed to avoid an unexpected voltage drop that accompanies the increase in device area,” Kato said.

An optical image of a highly transparent solar cell made with 2D atomic foil. (CREDIT: Toshiaki Kato)
“This is the highest value in a TMD-based solar cell with few layers,” the paper concludes. “These findings may contribute to the study of TMD-based NISCs from fundamental to truly industrialized stages.”
Details of their research were published in the journal Scientific Reports.
For more science and technology articles, see our New Innovations section on The bright side of the news.
Note: The documents provided above by Tohoku University. Content may be edited for style and length.
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