Zhang Youming, Wu Chengjun, Zhu Minrong, Miao Jingsheng
Shenzhen Key Laboratory of Polymer Science and Technology, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China.
Molecules. 2021 Oct 22;26(21):6386. doi: 10.3390/molecules26216386.
Three near-infrared emitters (, and ) were rationally designed and synthesized. Density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations showed that the introduction of mono- or di-methyl groups between the donors and acceptor could result in the spatial configuration changing greatly for and compared to their parent compound . The emission of had a more obvious hybridized local and charge transfer feature (HLCT) based on the influence of the steric hindrance of the methyl substituent. Attributed to their different spatial configurations and luminescence mechanisms, different emission wavelengths with photoluminescent quantum yields of 26%, 38% and 34% in toluene, as well as 24%, 27% and 31% in 4,4'-bis(N-carbazolyl)-1,1'-biphenyl (CBP) doped film, were observed for , and , respectively. The constructed organic light-emitting devices (OLEDs) displayed electroluminescence with emission peaks at 728, 693 and 710 nm, with maximum external quantum efficiencies of 1.58%, 1.33% and 3.02% for the , and -doped OLEDs, respectively. This work illustrated the effect of spatial configuration changes on the luminescence properties of donor-acceptor-type organic emitters.
合理设计并合成了三种近红外发光体（、和）。密度泛函理论（DFT）和含时密度泛函理论（TDDFT）计算表明，与母体化合物相比，给体和受体之间引入单甲基或二甲基会导致和的空间构型发生显著变化。由于甲基取代基的空间位阻影响，的发射具有更明显的局域与电荷转移混合特征（HLCT）。由于它们不同的空间构型和发光机制，在甲苯中的光致发光量子产率分别为26%、38%和34%，在4,4'-双（N-咔唑基）-1,1'-联苯（CBP）掺杂薄膜中的光致发光量子产率分别为24%、27%和31%，观察到、和的发射波长不同。构建的有机发光器件（OLED）显示出电致发光，发射峰分别位于728、693和710 nm，、和掺杂的OLED的最大外量子效率分别为1.58%、1.33%和3.02%。这项工作说明了空间构型变化对给体-受体型有机发光体发光性能的影响。
