Solar cells are a sustainable form of power generation that can significantly reduce environmental pollution. Among various types of solar cells, perovskite quantum dot solar cells have gained attention due to their lower cost of production and flexibility compared to conventional silicon solar cells.
The efficiency of perovskite quantum dot solar cells relies heavily on hole transport materials, which are responsible for charge transportation. However, the use of traditional hole transport materials in these cells can lead to rapid degradation due to dopants. Therefore, researchers have been exploring alternative hole transport materials that do not require dopants.
A team of scientists led by Professor Taiho Park and Ph.D. candidates Dae Hwan Lee and Seyeong Lim from the Department of Chemical Engineering at POSTECH has developed a new type of polymeric hole transport material that significantly improves the efficiency of perovskite quantum dot solar cells. The research findings have been published in ACS Energy Letters.
The team designed polymers for hole transport materials incorporating sulfur and selenium compounds. These polymers possess specific structural features, such as planarization and intermolecular arrangement, which enhance charge mobility. Additionally, the asymmetric alkyl substituents in the polymers promote molecular interactions, further improving the electrical properties of the solar cells.
To evaluate the effectiveness of the newly designed polymers, the researchers conducted tests using a control group. The results demonstrated that solar cells employing hole transport materials containing selenium compounds achieved a power conversion efficiency (PCE) of 15.2%, and even after 40 days, they maintained 80% of their initial PCE.
These findings highlight the ability of the newly developed hole transport materials to enhance charge mobility in perovskite quantum dot solar cells without the use of dopants. As a result, they achieve the highest PCE and improved stability in dopant-free solar cells.
Professor Taiho Park, the lead researcher, stated that these research findings represent a significant shift from conventional charge transport materials and are expected to contribute to future advancements in solar cell technology.
Source: Pohang University of Science and Technology