Correlating Acceptor Structure and Blend Nanostructure with the Photostability of Nonfullerene Organic Solar Cells. Issue 10 (9th August 2022)

• Record Type: Journal Article
• Authors: Paleti, Sri Harish Kumar; Hultmark, Sandra; Ramos, Nicolas; Gasparini, Nicola; Emwas, Abdul-Hamid; Martin, Jaime; Müller, Christian; Baran, Derya
• Is Part Of: Solar RRL. Volume 6:Issue 10(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-08-09
• Subjects: ITIC -- nanostructure -- nonfullerene -- organic solar cell -- photostability -- stability; Solar energy -- Periodicals; Photovoltaic power generation -- Periodicals; Solar energy -- Research -- Periodicals; Photovoltaic power generation -- Research -- Periodicals; Periodicals; 333.7923
• DOI: 10.1002/solr.202200436
• Languages: English
• ISSNs: 2367-198X

Abstract

Abstract : The formation of photoinduced traps resulting in the loss of electron mobility deteriorates the performance of organic solar cells under continuous light soaking. The genesis of these loss mechanisms is elucidated by examining the structural stability of halogenated ITIC derivative films and the phase behavior of the respective binary systems by blending with the donor polymer PBDBT‐2F. Under constant illumination, ITIC‐4Cl is found to maintain its structural integrity, whereas fluorine on the peripheral moieties of ITIC‐4F undergoes chemical substitution to form a mixture of ITIC and ITIC‐4F. Thermal analysis of the light‐soaked binary films reveals that ITIC‐4Cl loses its crystalline phase while the crystallinity of ITIC‐4F does not undergo changes. Further, it is shown that the addition of a small amount of ITIC‐4F as a third component hinders the loss of ITIC‐4Cl crystalline phase in bulk heterojunction blends through the formation of cocrystals. These results suggest that long‐range ordering of NFAs does not necessarily improve the photostability of organic solar cells and that the addition of a third component, irrespective of the crystalline nature, can prevent changes in bulk heterojunction blend nanostructure. Abstract : Herein, fill factor roll‐off of binary and ternary solar cells with the best power conversion efficiency of 11.6% is shown. By addition of a third component (ITIC‐4F), an enhancement of photostability compared to the binary devices, PM6:ITIC‐4F and PM6:ITIC‐4Cl, is obtained. This is because the addition of a third component forms an acceptor cocrystal and inhibits the dissolution of ITIC‐4Cl crystals.