New Interlayer Boosts Efficiency in Tandem Solar Cells

• Revolutionizing solar energy: a groundbreaking interlayer boosts efficiency and stability in perovskite-silicon tandem cells, unlocking new potential for sustainable power generation!

An international team of researchers has developed an effective interlayer using morpholinium bromide (MLBr) to enhance electron transport in wide bandgap and perovskite-silicon tandem solar cells. By optimizing piperidinium bromide (PpBr) with an additional oxygen atom, they created an interlayer that minimizes energy band mismatches between the perovskite and C60 layers while also passivating defects.

The champion MLBr single junction solar cell achieved a power conversion efficiency (PCE) of 21.9%, while the monolithic MLBr perovskite-silicon tandem cell reached 28.8%. Notably, both types retained over 97% of their initial efficiency after 400 thermal cycles, addressing stability issues commonly seen with other interlayers like LiF. This cost-effective innovation paves the way for improved perovskite-based multi-junction devices.

How does morpholinium bromide improve efficiency and stability in tandem solar cells?

- Enhanced Electron Transport: Morpholinium bromide (MLBr) plays a crucial role in facilitating efficient electron transport within tandem solar cells. Its molecular structure allows it to create a highly conductive pathway for electrons, which minimizes energy losses during the charge transport process.

- Reduction of Energy Band Mismatches: The optimized MLBr interlayer helps to bridge energy gaps between different layers in tandem solar cells. By effectively aligning the energy levels of the perovskite and C60 layers, MLBr reduces band mismatches that often hinder performance and efficiency.

- Defect Passivation: One of the significant advantages of using morpholinium bromide is its ability to passivate defects at the interface between layers. This reduces trap states that can capture charge carriers, leading to improved overall performance in terms of efficiency and stability.

- Thermal Stability: Research indicates that MLBr-based devices display remarkable thermal stability, maintaining more than 97% of their initial efficiency after undergoing 400 thermal cycles. This makes them more resilient compared to other interlayers, which often suffer from degradation under temperature fluctuations.

- Cost-Effectiveness: MLBr is noted for being a cost-effective solution in the manufacturing of solar devices. Its availability and low production costs ensure that the implementation of this technology can be economically viable, encouraging wider adoption and development of advanced solar cells.

- Wide Bandgap Compatibility: The incorporation of MLBr allows for improved performance in wide bandgap materials, which are essential for the efficiency of tandem solar cells. This adaptability means that MLBr can be employed in various configurations, enhancing design flexibility for future solar technologies.

- Encouragement of Multi-Junction Designs: The advancements brought by MLBr pave the way for the development of more efficient perovskite-based multi-junction solar cells. These cells have the potential to harvest a broader spectrum of sunlight, thereby increasing the overall energy conversion capabilities beyond traditional single-junction solar cells.

- Partnership with Existing Technologies: By synergizing with existing technologies such as perovskite and silicon, MLBr helps in creating more efficient solar devices without overhauling current manufacturing processes. This partnership ensures a smoother transition into more advanced solar energy systems while retaining compatibility with established practices.

- Implications for Future Research: The success of MLBr in enhancing the performance of tandem solar cells opens up significant avenues for further research. Scientists are now motivated to explore other novel materials and their combinations, seeking additional improvements in efficiency, stability, and cost for next-generation solar technologies.