Researchers Develop Molecule to Boost Tandem Solar Cell Efficiency

A research team led by Prof. Ye Jichun from the Ningbo Institute of Materials Technology and Engineering (NIMTE) of the Chinese Academy of Sciences has created an innovative cage-like diammonium chloride molecule. This development significantly minimizes interfacial energy losses in perovskite/silicon tandem solar cells (TSCs), enhancing both efficiency and stability. The findings were published in Nature Communications.

TSCs have garnered attention in the photovoltaic sector due to their potential for high efficiency and cost effectiveness. Despite a theoretical efficiency limit of 45.1%, there remains considerable room for improvement, particularly concerning wide-bandgap perovskite top cells. One of the primary obstacles to achieving this limit is the substantial interfacial energy loss at the perovskite/electron-selective contact interface.

To tackle this challenge, the research team synthesized the multifunctional cage-like diammonium chloride molecule, which was integrated into the perovskite/C60 interface. This novel molecule helps reduce film defects and modulate the interfacial dipole, effectively minimizing energy losses.

Significant Efficiency Gains

Utilizing this new approach, the researchers fabricated perovskite solar cells with a bandgap of 1.68 eV. These cells achieved power conversion efficiencies (PCEs) of 22.6% on devices with a 0.1 cm² active area and 21.0% on those with a 1.21 cm² active area. When these optimized perovskite top cells were integrated into a 1.0 cm² monolithic TSC, the tandem device reached an impressive PCE of 31.1%.

Moreover, the tandem device exhibited long-term operational stability. After 1,020 hours of continuous maximum power point tracking under ambient conditions, it retained 85% of its initial efficiency. This breakthrough in addressing critical interfacial issues marks a significant step toward the advancement of efficient and stable perovskite-based tandem photovoltaic technologies.

The implications of this research extend beyond laboratory findings. By providing a solution to interfacial energy losses, the work of Prof. Ye Jichun and his team could pave the way for the next generation of solar cells, potentially transforming the landscape of renewable energy. As the world increasingly seeks sustainable energy solutions, advancements like these highlight the ongoing efforts to harness the power of solar technology more effectively.