Near-infrared absorbing polymer acceptors enabled by selenophene-fused core and halogenated end-group for binary all-polymer solar cells with efficiency over 16%. (February 2022)

• Record Type: Journal Article
• Authors: Fan, Qunping; Fu, Huiting; Luo, Zhenghui; Oh, Jiyeon; Fan, Baobing; Lin, Francis; Yang, Changduk; Jen, Alex K.-Y.
• Is Part Of: Nano energy. Volume 92(2022)
• Publication Date: 2022-02
• Subjects: All-polymer solar cells -- Halogenation -- Near-infrared absorbing polymer acceptors -- Power conversion efficiencies -- Selenophene; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2021.106718
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: Due to the vigorous development of polymerized small-molecule acceptors (PSMAs), all-polymer solar cells (all-PSCs) have made tremendous advancement recently. However, their power conversion efficiencies (PCEs) are still restricted by the lack of PSMAs with desirable optoelectronic properties, especially the ability to capture the near-infrared photons. To resolve this, two near-infrared absorbing PSMAs, namely PY2Se-F and PY2Se-Cl, with a selenophene-fused core and halogenated end-group are developed. Combining the synergistic effects of selenium and fluorine (F)/chlorine (Cl) substitutions in broadening absorption and enhancing intermolecular interactions, PY2Se-F and PY2Se-Cl show significantly red-shifted absorption (30–40 nm) and reasonably deep-shifted lowest unoccupied molecular orbital (LUMO) levels compared with the pristine PY2S-H and fluorinated PY2S-F. When replacing F with Cl on the end-group, the PY2Se-Cl shows a better blend morphology with polymer donor PM6, compared with the PY2Se-F-based one, leading to better charge transport. As a result, the PM6:PY2Se-Cl-based all-PSCs achieve an impressive PCE of 16.1% with both high short-circuit current density ( J sc ) of 24.5 mA cm −2 and fill factor (FF) of 0.743, which are among the highest values in the reported binary all-PSCs so far. Notably, this is the first example of chlorinated end-group derived PSMAs. Combining with the low-cost merit of chlorination, PY2Se-Cl shows great potential in the practical applications of efficient all-PSCs. Graphical Abstract: A novel near-infrared absorbing polymer acceptor PY2Se-Cl with a selenophene-fused core and chlorinated end-group was developed. In binary all-PSCs, PY2Se-Cl achieved an impressive PCE of 16.1% with both high J sc of 24.5 mA cm −2 and FF of 0.743. Combining the low-cost merit of chlorination, PY2Se-Cl shows great potential in the applications of efficient all-PSCs. ga1 Highlights: A novel NIR-absorbing polymer acceptor PY2Se-Cl with a selenophene-fused core and chlorinated end-group was developed. In binary all-PSCs, PY2Se-Cl achieved an impressive PCE of 16.1% with both high J sc (24.5 mA cm −2 ) and FF (0.743). Combining the low-cost merit of chlorination, PY2Se-Cl shows great application potential in efficient all-PSCs.