Solar panels have revolutionized the way we produce and consume electricity by allowing individuals and businesses to generate their own power at low costs or even sell excess power back to the grid.
As technology continues to improve and become more efficient, it is expected to play a larger role in reducing global greenhouse gas emissions.
One potential way to expand the reach of solar power is to integrate it into everyday materials and technologies in a way that is unobtrusive.
Materials scientists are working on creating transparent solar panels that can be placed on windows, display screens, or even human skin.
While progress has been made using advanced solid materials, current designs still allow less than 70% of incoming light to pass through, which is not sufficient for the panels to blend in with their surroundings.
Tesla is also working on transparent solar panels to power homes.
The new design
A team of researchers in Japan has made significant progress in developing transparent solar panels. The team, led by Toshiaki Kato at Tohoku University, used a conductive material called indium tin oxide (ITO), which is transparent and colorless, as the base for their solar cell.
They exposed the ITO electrode to a vapor of tungsten disulphide (WS2) under specific conditions, resulting in an atom-thick layer of WS2 on the ITO surface, which acts as a semiconductor.
By coating the ITO with thin metals and placing an insulating layer between the ITO and WS2, the researchers were able to precisely control the “contact barrier” between the two materials, which is the energy needed for electrons to pass from one material to the other.
When incoming photons are absorbed by the WS2 layer, the electrons jump between the semiconductor’s two energy bands, converting the material from an insulator to a conductor.
This process generates a voltage between the charge carriers, allowing electrical energy to be harvested from the solar panel.
Solar glass windows
Efficiency and transparency
Researchers in Japan have developed a manufacturing approach for transparent solar panels that are significantly more efficient at converting incoming light into electricity than existing designs.
The team, led by Toshiaki Kato at Tohoku University, used a conductive material called indium tin oxide (ITO) as the base for their solar cell and coated it with a thin layer of tungsten disulphide (WS2).
By carefully adjusting the materials and layout of the solar cell, the team was able to drastically increase the voltage between the ITO and WS2, making the device over 1,000 times more effective at converting light into electricity.
The solar cell also allowed 79% of incoming light to pass through, making it significantly more transparent than previous designs.
The team also demonstrated that the high performance of the solar cell could be maintained on larger scales, with solar cells as large as 1cm2 maintaining a high level of efficiency.
The transparent solar cell has the potential to be integrated into a wide range of electronic devices, allowing them to harness the sun’s energy without the need for an external power supply.
Transparent solar cells
This new technology for transparent solar panels has the potential to be a significant advancement in the integration of solar technology into a variety of existing technologies.
The panels have demonstrated a significant increase in both transparency and efficiency compared to previous designs, making them a potential candidate for discreetly harvesting solar energy.
If the technology becomes more widely available in the future, it could enable a range of electronic devices to harness the sun’s energy without the need for an external power supply or connection to the grid.
