[Advanced Functional Materials (IF>19.924)] The research team of Professor Changduk Yang from UNIST, South Korea developed organic solar cells with excellent stability and 18.2% efficiency
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Highlights
- Professor Changduk Yang’s research team at UNIST, South Korea developed a new electron-transporting material H75, achieving 18.2% efficiency in organic solar cells.
- H75-based cells showed only 5% efficiency decay under different aging conditions and identified excellent performance on stability.
- The Benzamide-Functionalized in H75 improved the power conversion efficiency and structural stability of the solar cells. in H75 improved the power conversion efficiency and structural stability of the solar cells.
Background
Organic solar cells are considered the next-generation photovoltaic technology due to their simple processing and low cost. However, the obstacle to commercialization is the inefficiency and instability that need to be refined. To ensure realizing the practical application that enhancing efficiency and stability is the key to enabling real-world applications of organic solar cells further.
Results
Professor Changduk Yang’s team (UNIST, South Korea) designed a new electron transporting material, H75, boosting the power conversion efficiency of H75-based organic solar cells to 18.2%. Compared to conventional cells, H75-based devices showed superior stability under different aging conditions, with <5% efficiency decay after 1500 h storage and >1000 h T80 lifetime under light soaking and thermal stress tests.
UNIST is located in Ulsan Metropolitan City, known as the industrial capital of South Korea, and is one of the four major national science and technology institutes in South Korea (including KAIST, GIST and DGIST). Since its establishment, UNIST has been devoted to developing itself into the most prominent national university and a world-leading institute of science and engineering. After installing Enlitech’s QE-R quantum efficiency system in 2019, UNIST successively achieves the records of best perovskite solar cell efficiency in the efficiency chart verified by NREL in Aug 2020 (25.5%), Jan 2022 (25.7%) and Dec 2022 (25.8%).
The researchers used Enlitech’s QE-R system to characterize the efficiency and quantum efficiency of the solar cells. Results show H75 substantially improved the power conversion efficiency and stability of the devices. They attributed such enhancements to the Benzamide-Functionalized in H75, which facilitated film formation, energy level alignment, and reduced effects of aggregation.
This article demonstrates the enormous potential of H75 in constructing highly efficient and stable organic solar cells. With further optimization, H75-based organic PV devices will surely be worthy of expectations and make even greater contributions to renewable energy development.
Methods
- H75 was synthesized via Suzuki coupling reactions using 1, 7-Dibromoperylene-3,4,9,10-tetracarboxylic acid as the initial material, introducing Benzamide-Functionalized into the ETL.
- Organic solar cells with the D18:Y6 system were fabricated using H75, PDIN, and PDINN as the ETL and power conversion efficiency were tested.
- Stability tests including long-term storage, thermal stress, light soaking, damp heat, and air exposure were performed on unencapsulated devices.
- H75 was characterized by 1H NMR, 13C NMR, mass spectrometry, TGA, UV-Vis to analyze its chemical structure, thermal and photostability.
- Morphology of H75 films was studied by AFM, GIWAXS to elucidate its molecular design advantages.
Conclusion
This article developed H75 which substantially boosted the efficiency and stability of organic solar cells, providing a molecular design strategy to construct high-performance stable ETLs.
Keywords
QE-R、UNIST
Reference
Published on May 19, 2022.
https://doi.org/10.1002/adfm.202303386