Over the past few years, there has been a growing interest in the development of solar cells using organic materials, particularly perovskite. These organic solar cells offer a range of advantages over traditional silicon-based solar cells, including lower fabrication costs, increased flexibility, and enhanced tunability. However, despite these benefits, organic solar cells have not yet reached the same level of efficiency as silicon solar cells.
One of the proposed strategies to improve the efficiency and stability of organic solar cells is to combine them with cells utilizing mixed halide wide-bandgap perovskites, creating perovskite/organic tandem solar cells. While this approach shows great potential in achieving high power conversion efficiencies (PCEs) and stability, it is hindered by a process known as phase segregation. This phase segregation degrades the performance of wide-bandgap perovskite cells, impacting the recombination processes in the tandem solar cells’ interconnecting layer.
Researchers at Soochow University’s Suzhou Key Laboratory of Novel Semiconductor-optoelectronic materials and devices have recently developed a strategy to combat phase segregation in wide-bandgap perovskites. Their method involves the use of a pseudo-triple-halide alloy incorporated in mixed halide perovskites based on iodine and bromine. By introducing pseudo-halogen thiocyanate ions into the perovskites, the researchers were able to prevent halide elements from separating within the cells.
The addition of thiocyanate ions slowed down crystallization in the perovskite cells, preventing ion migration and facilitating the movement of electric charge. This ultimately led to a reduction in energy loss and an improvement in overall performance and stability. Initial tests on perovskite/organic tandem solar cells incorporating this strategy showed a significant increase in PCE, reaching 25.82% with a certified PCE of 25.06% and an operational stability of 1,000 hours.
Looking ahead, the methodology introduced by the researchers could be further developed and applied to a wider range of wide-bandgap perovskites with different compositions. This has the potential to pave the way for the creation of more efficient and stable perovskite/organic photovoltaic systems that are capable of withstanding varying light intensities and operating for extended periods of time without deterioration.
The advancement in perovskite/organic tandem solar cells represents a significant step forward in the field of solar energy. By addressing the challenges of efficiency and stability through innovative strategies, researchers are moving closer to realizing the full potential of organic solar cells. With further research and development, these advancements could play a crucial role in shaping the future of renewable energy technologies.
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