Yu Xiao-Qing, Sun Cai, Liu Bin-Wen, Wang Ming-Sheng, Guo Guo-Cong
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences (CAS), 155 Yangqiao Road West, 350002, Fuzhou, Fujian, China.
University of Chinese Academy of Sciences, No.19A Yuquan Road, 100049, Beijing, China.
Nat Commun. 2020 Mar 4;11(1):1179. 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-Fe or Zn-Fe 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.
将半导体的光响应范围扩展到整个紫外-可见（UV）-短波近红外（SWIR）区域（约200-3000nm）非常有助于降低光电探测器的复杂性和成本，或提高太阳能电池的功率转换效率。基于有机的半导体所观察到的光响应上限约为1800nm，远远无法覆盖UV-SWIR区域。在此，我们开发了一种氰化物桥连层定向插层方法，并获得了一系列具有多光谱光响应的基于双紫精的二维半导体。在这些化合物中，具有近平面结构的无限π堆积氧化还原活性N-甲基联吡啶阳离子被氰化物桥连的Mn-Fe或Zn-Fe层夹在中间。无限π堆积的N-甲基联吡啶组分之间的自由基-π相互作用有利于吸收范围的扩展。两种半导体都表现出光/热诱导的颜色变化，并形成稳定的自由基。它们在至少355-2400nm范围内具有本征光电流响应，这超过了所有已报道的已知单组分有机基半导体的值。
