Sun Cai, Yu Xiao-Qing, 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, Fuzhou, Fujian, 350002, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
Angew Chem Int Ed Engl. 2019 Jul 8;58(28):9475-9478. doi: 10.1002/anie.201904121. Epub 2019 May 27.
Breaking the intrinsic rule of semiconductors that conductivity increases with increase of temperature and realizing a dramatic dropping of conductivity at high temperature may arouse new intriguing applications, such as circuit overload or over-temperature protecting. This goal has now been achieved through T-type electron-transfer photochromism of one organic semiconductor assembled by intermolecular cation⋅⋅⋅π interactions. Conductivity of the viologen-based model semiconductor (H bipy)(Hox) (H bipy=4,4'-bipyridin-1,1'-dium; ox=oxalate) increased by 2 orders of magnitude after photoinduced electron transfer (a record for photoswitchable organic semiconductors) and generation of radical cation⋅⋅⋅π interactions, and fell by approximately 81 % at 100 °C through reverse electron transfer and degeneration of the radical cation⋅⋅⋅π interactions. The model semiconductor has at least two different electron transfer pathways in the decoloration process.
打破半导体电导率随温度升高而增加这一固有规律，并实现高温下电导率的急剧下降，可能会引发新的有趣应用，比如电路过载或过温保护。目前，通过由分子间阳离子⋅⋅⋅π相互作用组装而成的一种有机半导体的T型电子转移光致变色，这一目标已得以实现。基于紫精的模型半导体（H bipy）（Hox）（H bipy = 4,4'-联吡啶-1,1'-二鎓；ox = 草酸盐）在光致电子转移（这是可光开关有机半导体的一项纪录）以及产生自由基阳离子⋅⋅⋅π相互作用后，电导率增加了2个数量级，而在100 °C时，通过反向电子转移和自由基阳离子⋅⋅⋅π相互作用的退化，电导率下降了约81 %。该模型半导体在褪色过程中至少有两条不同的电子转移途径。
