Extended Conjugation and End-Group Modification of Silicon-Bridged Carbazole-Based Non-Fullerene Acceptors in Indoor Organic Photovoltaics

• Published in: ACS applied energy materials Vol. 5; no. 11; pp. 13851 - 13860
• Main Authors: Su, Yi-Jia, Wu, Shang-Hsuan, Huang, Sheng-Ci, Nie, HeBing, Chen, Tsung-Wei, Chen, Jiun-Tai, Hsu, Chain-Shu
• Format: Journal Article
• Language: English
• Published: American Chemical Society 28.11.2022
• Subjects: end-group modification; non-fullerene acceptor; extended conjugation; organic photovoltaics; indoor application
• ISSN: 2574-0962; 2574-0962
• DOI: 10.1021/acsaem.2c02472

In this work, the strategies of extended conjugation and end-group modification are used to design four non-fullerene acceptors, DTTSiC-2F, DTTSiC-2Cl, DTTSiC-4F, and DTTSiC-4Cl. To investigate the influence of extended conjugation and end-group modification, grazing-incidence wide-angle X-ray scattering is used to analyze the packing alignment of the molecules. Photovoltaic performances under both AM 1.5G and indoor conditions are examined. Owing to the push-pull effect, DTTSiC-2F and DTTSiC-2Cl manifest a much higher lowest unoccupied molecular orbital, resulting in higher V OC. DTTSiC-4F and DTTSiC-4Cl manifest higher J SC due to the red-shifted and stronger absorption. Under indoor conditions, devices based on PM6:DTTSiC-4Cl exhibit a power conversion efficiency of 19.18% with a V OC of 0.79 V, a J SC of 92.15 μA/cm2, and an FF of 73.21%, proving that extended conjugation and end-group modification are particularly promising strategies for developing indoor organic photovoltaics.