Directed self-assembly of viologen-based 2D semiconductors with intrinsic UV–SWIR photoresponse after photo/thermo activation

• Published in: Nature communications Vol. 11; no. 1; p. 1179
• Main Authors: Yu, Xiao-Qing, Sun, Cai, Liu, Bin-Wen, Wang, Ming-Sheng, Guo, Guo-Cong
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 04.03.2020; Nature Publishing Group; Nature Portfolio
• Subjects: 639/301/1005/1007; 639/301/119/1000; 639/301/119/995; 639/638/298/917; Broadband; Cations; Cyanides; Electronics industry; Energy conversion efficiency; Humanities and Social Sciences; Intercalation; multidisciplinary; Organic semiconductors; Photoelectric effect; Photoelectric emission; Photometers; Photoresponse; Photovoltaic cells; Planar structures; Science; Science (multidisciplinary); Self-assembly; Semiconductors; Short wave radiation; Solar cells; Solar power
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-020-14986-7

Extending photoresponse ranges of semiconductors to the entire ultraviolet–visible (UV)–shortwave near-infrared (SWIR) region (ca. 200–3000 nm) is highly desirable to reduce complexity and cost of photodetectors or to promote power conversion efficiency of solar cells. The observed up limit of photoresponse for organic-based semiconductors is about 1800 nm, far from covering the UV–SWIR region. Here we develop a cyanide-bridged layer-directed intercalation approach and obtain a series of two viologen-based 2D semiconductors with multispectral photoresponse. In these compounds, infinitely π-stacked redox-active N -methyl bipyridinium cations with near-planar structures are sandwiched by cyanide-bridged Mn II –Fe III or Zn II –Fe III layers. Radical–π interactions among the infinitely π-stacked N -methyl bipyridinium components favor the extension of absorption range. Both semiconductors show light/thermo-induced color change with the formation of stable radicals. They have intrinsic photocurrent response in the range of at least 355–2400 nm, which exceeds all reported values for known single-component organic-based semiconductors. Developing new materials with broadband photoresponse is highly desirable for realizing commercial photodetectors with extended detection ranges. Here, the authors report a cyanide-bridged layer-directed intercalation approach to design viologen compounds with enhanced broadband photoresponse.