The demand for renewable energy has been on the rise due to increased energy prices and a growing concern for environmental sustainability. Solar power, in particular, has seen significant growth with the deployment of solar parks. However, the efficiency of solar panels remains a challenge. Current technologies can only convert a quarter of the sun’s energy to electricity. In a quest to improve solar panel efficiency, a research group from the Center for Physical Sciences and Technology (FTMC, Lithuania), partnered with Tallinn University of Technology (Estonia) to explore the synthesis of new materials that could complement silicon solar cell technologies and increase overall efficiency.
To overcome the efficiency limitations of traditional solar cells, the research team focused on creating a device known as a multijunction solar cell. This device combines different technologies to increase the conversion of solar energy to electricity. Theoretically, multijunction solar cells can convert nearly half of the sun’s energy into electricity. However, the production of such devices is more complex, requiring the use of novel materials while also considering cost and sustainability factors.
The research group focused on semiconductors with a chemical structure typical of perovskite materials. They explored compounds where sulfur/selenium replaced oxygen or halogens, with abundant and non-toxic metals as A and B elements. The team successfully synthesized a new material, tin zirconium titanium selenide, using a solid-state reaction method. They found that the Sn(ZrxTi1-x)Se3 alloy was the most promising for photovoltaic applications.
The Impact of Titanium
The introduction of titanium, with a concentration of up to 44%, had a significant effect on both the optical and electrical properties of the Sn(ZrxTi1-x)Se3 alloy. The higher the concentration of titanium, the more the absorption edge of the alloy shifted towards the short-wavelength infrared spectrum region. This region of the infrared spectrum, which is not absorbed by conventional silicon solar cells, can be harnessed by Sn(ZrxTi1-x)Se3 semiconductors with high titanium concentration. This allows for the absorption of additional energy, boosting the overall efficiency of Si-based multijunction devices.
Enhanced Absorption Coefficient
In addition to the shift in absorption edge, the introduction of titanium in the Sn(ZrxTi1-x)Se3 alloys significantly enhanced the absorption coefficient. Materials with a high absorption coefficient are desirable for solar cells, as even a very thin layer is sufficient to absorb all incoming sunlight. The researchers found that a layer 20 times thinner than a strand of hair could absorb the entire spectrum of light from the sun.
The research conducted by the FTMC and Tallinn University of Technology marks an important milestone in the development of sustainable materials for multijunction solar cells. The Sn(ZrxTi1-x)Se3 alloy with high titanium concentration shows great potential for application in the infrared region, extending the efficiency range of solar cells. This research aligns with the goal of utilizing abundant and non-toxic elements, reducing reliance on critical raw materials.
The Next Steps
The successful synthesis of the Sn(ZrxTi1-x)Se3 alloy is just the beginning. The research team aims to continue their work by developing thin films of the alloy. This will allow for the fabrication and testing of solar devices using this novel material. The ultimate goal is to enhance the efficiency of solar panels and contribute to the advancement of renewable energy technology.
The research conducted by the FTMC and Tallinn University of Technology offers promising insights into the future of solar power. By synthesizing novel materials and exploring multijunction solar cell technologies, the efficiency of solar panels can be greatly improved. The introduction of titanium in the Sn(ZrxTi1-x)Se3 alloy shows significant potential for enhancing absorption of short-wavelength infrared light. This discovery paves the way for the development of sustainable materials that can increase the overall efficiency of solar modules. As the world continues to shift towards renewable energy sources, research like this is crucial in driving the advancement of solar power technology.
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