Scientists at Martin Luther University Halle-Wittenberg (MLU) have made a groundbreaking discovery that could revolutionize the solar energy industry. They have developed a new technique to increase the efficiency of solar cells by a factor of 1,000 (or over 99,000%).
By layering crystalline structures of barium titanate, strontium titanate, and calcium titanate in a lattice pattern, the team achieved this significant advancement. Their findings have been recently published in the journal Science Advances.
Barium titanate: an alternative to silicon
Unlike traditional silicon-based solar cells, which have limitations in efficiency, researchers are exploring alternative materials such as ferroelectrics. Barium titanate, a ferroelectric mixed oxide composed of barium and titanium, exhibits a unique asymmetric structure that generates electricity from light due to its spatially separated positive and negative charges.
Unlike silicon, ferroelectric crystals do not require a pn junction to produce a photovoltaic effect. This makes the production of solar panels easier.
However, the absorption of sunlight in pure barium titanate is low, resulting in relatively low photocurrent. The breakthrough research demonstrates that combining extremely thin layers of different materials significantly enhances the solar energy yield.
Research findings
Dr. Akash Bhatnagar, a physicist from MLU’s Centre for Innovation Competence SiLi-nano, emphasized the significance of alternating a ferroelectric material with a paraelectric material. Although the latter does not possess separated charges, it can become ferroelectric under specific conditions, such as low temperatures or slight modifications to its chemical structure.
Bhatnagar’s research group discovered that alternating the ferroelectric layer not only with one but with two different paraelectric layers greatly enhances the photovoltaic effect.
The German scientists positioned barium titanate between strontium titanate and calcium titanate by vaporizing the crystals with a high-power laser and redepositing them on carrier substrates. This resulted in a material comprising 500 layers that is approximately 200 nanometers thick. The diagram below illustrates the solar cell design.
Source: Uni Halle / Yeseul Yun
During the photoelectric measurements, the new material was exposed to laser light, and the results surprised the research group. The current flow was up to 1,000 times stronger compared to pure barium titanate of similar thickness.
Bhatnagar explained that the increased interaction between the lattice layers seems to lead to a higher permittivity. This allows electrons to flow more easily due to excitation by the light photons.
The measurements also demonstrated that this effect is highly stable over a six-month period.
Further investigation is required to determine the exact cause of this remarkable photoelectric effect. However, Bhatnagar is confident that the potential shown by this new concept can be utilized in practical applications for solar panels.
The layered structure demonstrates higher efficiency across all temperature ranges compared to pure ferroelectrics. Additionally, these crystals are more durable and do not require special packaging.
The ramifications of the research
This breakthrough has significant implications for the solar industry. Solar panels made from this new material would be considerably more efficient and cost-effective than silicon-based solar cells. They would also require less space to generate the same amount of electricity, making them ideal for limited space areas like urban environments.
Solar energy is rapidly growing as a renewable energy source, with projected high demand for solar panels in the future. According to Brighter Side News, solar power will become the largest source of electricity by 2050, making up around one-third of global electricity generation.
However, current solar panels need to improve their efficiency to achieve this goal.
The MLU research team’s discovery could play a crucial role in the solar energy transition. By enhancing the photovoltaic effect of ferroelectric crystals, the new material has the potential to significantly boost solar panel efficiency. This advancement would not only make solar energy more cost-effective but also reduce reliance on fossil fuels and combat climate change.
Moving forward, the German scientists will focus on further investigating the properties of the new material and improving its performance.
Bhatnagar mentioned that the research team is still working on understanding how the different materials interact to produce a strong photovoltaic effect. Additionally, the team aims to explore if the material’s efficiency can be further increased by modifying its composition or structure.
The research team at MLU is currently working on developing a new prototype solar cell based on their recent findings. If successful, this could pave the way for the production of commercial solar panels using the new material within the next few years.
