New Ligand Strategy Enhances Inorganic Perovskite Solar Cells

• Revolutionizing solar power, researchers boost perovskite tandem cells' efficiency to record heights while enhancing stability, paving the way for durable, next-gen renewable energy solutions.

Researchers from several institutions, including South China University of Technology and the Chinese Academy of Sciences, have developed a new ligand evolution (LE) strategy to enhance the performance of all-inorganic narrow bandgap (NBG) perovskite tandem solar cells (IPTSCs). By substituting organic cations with inorganic ones, they increased long-term stability in perovskite solar cells. Nonetheless, challenges in 2-terminal IPTSC fabrication due to deep trap states hindered progress.

Using p-toluenesulfonyl hydrazide (PTSH) in their LE strategy, the team improved film formation and reduced deep traps, achieving a record efficiency of 17.41% for the CsPb0.4Sn0.6I3:LE device. When combined with a top-cell, these IPTSCs reached a champion efficiency of 22.57% (certified 21.92%). The cells also demonstrated excellent durability, maintaining 80% efficiency after extended exposure to high temperatures, signaling a potential breakthrough in stable and efficient solar cell technology.

How does the new ligand evolution strategy improve perovskite tandem solar cell performance?

The new ligand evolution (LE) strategy developed by researchers from multiple institutions enhances the performance of all-inorganic narrow bandgap (NBG) perovskite tandem solar cells (IPTSCs) in several key ways:

Increased Stability:

• The adoption of inorganic cations over organic ones contributes to improved long-term stability of the perovskite solar cells, reducing the likelihood of degradation under environmental stressors, such as moisture and temperature fluctuations.

Improved Film Formation:

• The introduction of p-toluenesulfonyl hydrazide (PTSH) in the LE strategy facilitates better film morphology, leading to more uniform layers. A well-formed film is crucial for effective charge transport and light absorption.

Reduction of Deep Trap States:

• The new ligand strategy helps to diminish the presence of deep trap states within the material, which can capture charge carriers and reduce overall device efficiency. Minimizing these traps enhances the charge mobility and overall power conversion efficiency.

Record Efficiency Achievements:

• The implementation of the LE strategy culminated in a significant efficiency record of 17.41% for the CsPb0.4Sn0.6I3:LE device alone, underscoring the effectiveness of the approach. When paired with a top-cell, these devices attained a champion efficiency of 22.57%, demonstrating their competitive edge.

Enhanced Durability:

• The IPTSCs exhibited remarkable durability, with the capacity to maintain 80% of their efficiency even after prolonged exposure to high temperatures. This characteristic is vital for commercial applications where solar cells must withstand varying climatic conditions.

Potential for Commercialization:

• With these enhancements, the LE strategy not only advances scientific understanding but also paves the way for possible commercialization of high-performance IPTSCs, appealing to industries seeking reliable and efficient renewable energy solutions.

Broader Implications for Tandem Solar Technologies:

• This innovation could lead to improved efficiency in other types of tandem solar cell technologies, potentially impacting the broader renewable energy landscape by providing more efficient energy harvesting solutions.

Research and Development Opportunities:

• The findings may catalyze further research into other ligand modifications and synthesis methods, encouraging exploration of different materials and techniques to maximize the efficiency and stability of perovskite solar cells.

By leveraging these advancements, researchers aim to address some of the long-standing challenges in the field of solar energy, moving closer to achieving practical and scalable solutions for sustainable energy generation.