Room temperature phosphorescence in longer-wavelength red light region found in benzothiadiazole-based dyes
Room temperature phosphorescence in longer-wavelength red light region found in benzothiadiazole-based dyes
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DOI：
10.1039/d3tc00162h
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发表时间：
2023-02-06
影响因子：
6.4
通讯作者：
Matsumoto, Taisuke
中科院分区：
文献类型：
--
作者：
Ishi-i, Tsutomu;Kichise, Rihoko;Matsumoto, Taisuke
由于其在生物成像和传感方面的发展，在较长波长红光区的室温磷光引起了相当大的兴趣。然而，红色磷光是高度受限的，因为从有机染料发射的磷光颜色大多限于蓝色、绿色和黄色区域中的较短波长。本文报道了一种含甲氧基和溴原子的苯并噻二唑类吸电子染料的红色磷光。虽然苯并噻二唑染料在单体状态下具有磷光的固有特性，但结晶固态下的磷光行为通过苯并噻二唑部分之间的pi中线水平椭圆pi相互作用、甲氧基之间的C-HMIDLINE HORIZONTAL ELLIPSISO相互作用和溴原子之间的BrMIDLINE HORIZONTAL ELLIPSISBr相互作用的聚集而辅助。在引入溴原子的重原子效应加速了体系间的跃迁后，这些多重分子间相互作用可以稳定给定的激发三重态，从而限制了非辐射通道，加速了磷光辐射。这种红色磷光可以被开发成具有关键电子受体部分、溴原子和甲氧基的其他染料。
Room temperature phosphorescence in the longer-wavelength red-light region has attracted considerable interest owing to its development in biological imaging and sensing. However, red phosphorescence is highly limited because the phosphorescence color emitted from organic dyes has mostly been restricted to shorter-wavelengths in the blue, green, and yellow regions. Red phosphorescence is observed in an electron-accepting benzothiadiazole dye bearing a methoxy group and bromine atom in the crystal solid state. Although the benzothiadiazole dye has an inherent characteristic of phosphorescence in the monomeric state, the phosphorescence behavior in the crystalline solid state is assisted secondarily by aggregation through pi MIDLINE HORIZONTAL ELLIPSIS pi interactions among benzothiadiazole moieties, C-HMIDLINE HORIZONTAL ELLIPSISO interactions among methoxy groups, and BrMIDLINE HORIZONTAL ELLIPSISBr interactions among bromine atoms. After the intersystem crossing accelerated by the heavy-atom effect of the introduced bromine atom, the given excited triplet state can be stabilized by these multiple intermolecular interactions, resulting in the restriction of the nonradiative channel and acceleration of the phosphorescence radiation. This red phosphorescence can be developed into other dyes bearing key electron-acceptor moieties, bromine atoms, and methoxy groups.