Solar energy has proven to be an invaluable resource in the face of increasing energy demands and growing environmental concerns. However, the efficiency of traditional silicon solar cell technologies still has room for improvement. Recognizing this need, a research group from the Center for Physical Sciences and Technology (FTMC, Lithuania), in collaboration with partners from Tallinn University of Technology (Estonia), embarked on a mission to synthesize new materials that could revolutionize solar panel efficiency. By developing a multijunction solar cell with a higher conversion rate, they aim to pave the way for more sustainable and cost-effective renewable energy solutions.
The best solar cell technologies currently available on rooftops have a limited ability to convert only a quarter of the sun’s energy into electricity. To overcome this limitation, the research team explored the concept of multijunction solar cells, which have the theoretical potential to convert almost half of solar energy into electricity. However, the production of multijunction solar cells is more complex, requiring the adoption of novel materials and manufacturing processes while maintaining cost-effectiveness and sustainability.
The research team’s focus was on semiconductors with a chemical structure typical of perovskite materials, namely ABX3 compounds. However, instead of using oxygen or halogens as in traditional perovskites, they explored compounds where X is sulfur or selenium, and A and B are abundant and non-toxic metals. Their groundbreaking research led to the synthesis of a new material for the first time – tin zirconium titanium selenide. This material, known as Sn(ZrxTi1-x)Se3 alloy, showed tremendous promise for photovoltaic applications.
The team discovered that introducing titanium into the Sn(ZrxTi1-x)Se3 alloy had a profound impact on both its optical and electrical properties. Interestingly, the higher the concentration of titanium, the more the absorption edge of the alloy shifted towards the short-wavelength infrared spectrum region. This part of the spectrum is typically not absorbed by conventional crystalline silicon solar cells, leading to energy loss. However, Sn(ZrxTi1-x)Se3 semiconductors with high titanium concentration displayed the ability to absorb short-wavelength infrared light, effectively converting it into additional energy. This breakthrough has the potential to significantly boost the overall efficiency of Si-based multi-junction solar devices.
Furthermore, the team observed that introducing titanium in the Sn(ZrxTi1-x)Se3 alloy greatly enhanced the absorption coefficient. Solar cells with high absorption coefficients are highly desirable, as even a thin layer of the material, just 20 times thinner than a strand of hair, is sufficient to absorb all incoming light from the sun. This finding opens up exciting possibilities for the development of sustainable materials with immense potential for multi-junction solar cell applications in the infrared region.
The Road Ahead: Synthesizing Thin Films for Solar Device Testing
The synthesis of a Sn(ZrxTi1-x)Se3 thin film marks the next significant milestone in the research team’s journey. This breakthrough will allow for the fabrication and testing of solar devices utilizing the novel material. It holds immense promise for the development of highly efficient and sustainable solar panels, paving the way for a greener and more sustainable future.
As the world continues to prioritize renewable energy solutions, the need for more efficient solar panels becomes increasingly evident. The research conducted by the Center for Physical Sciences and Technology and Tallinn University of Technology represents a significant step forward in achieving this goal. By delving into the realm of perovskite materials and developing new alloys, they have opened up new avenues for enhancing solar cell efficiency. The potential benefits of their work extend beyond just the energy sector – the use of abundant and non-toxic elements in their materials ensures compatibility with environmental sustainability practices. With further advancements and real-world testing, these novel materials hold the key to unlocking the full potential of solar energy and bringing us closer to a more sustainable future.