空间电荷转移热活性延迟荧光化合物合成和应用

Synthesis and Application of Thermally Activated Delayed Fluorescence Compounds with Space Charge Transfer Characteristic

设计合成了一种萘酰亚胺化合物oCz‐NI。通过理论计算,发现其具有扭曲的结构且电子给体和电子受体在空间上具有较小的距离,有利于实现空间电荷转移。不同溶剂中的光致发光光谱表明,oCz‐NI存在分子内电荷转移。进一步进行变温光谱测试,发现粉末的荧光强度随着温度升高而增大,这表明oCz‐NI具有热活性延迟荧光特性。上述结果表明采用空间电荷转移策略设计TADF材料具有可行性。热重分析和差示扫描量热法分析表明其具有良好的热稳定性,其5%失重温度为350℃,玻璃化转变温度为121℃。采用oCz‐NI作为发光材料制备的有机发光二极管,发射峰波长为496 nm,最大亮度为1405 cd/m^(2),最大外量子效率为4.11%。

A naphthalimide compound called oCz-NI was designed and synthesized.Theoretical calculations revealed a distorted structure with a small spatial distance between the electron donor and electron acceptor,which facilitated the space charge transfer.Photoluminescence spectroscopy in different solvents showed the presence of intramolecular charge transfer in oCz-NI.The variable temperature spectroscopy tests indicated an increase in the fluorescence intensity of the powder with rising temperature,suggesting the presence of thermally activated delayed fluorescence(TADF)properties in oCz-NI.These results highlight the feasibility of designing TADF materials using a space charge transfer strategy.The thermogravimetric analyses and differential scanning calorimetry measurements suggested good thermal stability of oCz-NI,while the thermal decomposition at 5%weight loss temperature was 350℃ and the glass transition temperature was 121℃.Furthermore,When oCz-NI was adopted to fabricate organic light-emitting diode,the electroluminescence peak wavelength was 496 nm,the maximum luminance was obtained to be 1405 cd/m^(2) and the maximum external quantum efficiency was achieved to be 4.11%.