基于供体-受体发射体的高效非对称连接用于有机发光二极管，以提高激子利用率。
Efficient donor-acceptor emitter based nonsymmetrical connection for organic emitting diodes with improving exciton utilization.
作者信息
Jayabharathi Jayaraman, Anudeebhana Jagathratchagan, Thanikachalam Venugopal, Sivaraj Sekar, Prabhakaran Annadurai
机构信息
Department of Chemistry, Material Science Lab, Annamalai University Annamalai Nagar Tamilnadu-608 002 India
出版信息
RSC Adv. 2020 Jan 23;10(7):4002-4013. doi: 10.1039/c9ra10513a. eCollection 2020 Jan 22.
A new strategy developed to construct blue emissive materials having an unsymmetrical connection with identical conjugated phenanthrimidazole groups results in the separation of the frontier orbitals and leads to donor-acceptor (D-A) architecture. The blue device with 2-(naphthalen-1-yl)-1-(4-(1-(naphthalen-1-yl)-1-phenanthro[9,10-]imidazol-2-yl)phenyl)-1-phenanthro[9,10-]imidazole (-PPI)/2-(naphthalen-1-yl)-1-(3-(1-(naphthalen-1-yl)-1-phenanthro[9,10-]imidazol-2-yl)phenyl)-1-phenanthro[9,10-]imidazole (-PPI) emissive layer ( - 434/420 nm) shows high efficiencies: current efficiency ( ) - 5.83/3.56 cd A; power efficiency ( ) - 5.73/3.48 lm W; external quantum efficiency ( ) - 8.98/6.48% at 3.0 V. Their cyano derivatives, -CNPPI/-CNPPI ( - 422/406 nm) exhibit maximum efficiencies ( - 6.28/4.38 cd A; - 6.14/4.01 lm W; - 9.01/6.72%) at 2.9 V compared to the -PPI/-PPI devices. The weak charge transfer in the D-A emitters results in deep blue emission. The anisotropic structural characteristics of -PPI, -CNPPI, -PPI and -CNPPI induced horizontal dipole orientation in films and enhanced EL efficiency. These bipolar materials with suitable triplet energy can be used as hosts in green as well as red phosphorescent organic light emitting devices (PHOLEDs). The green/red device ( - 504/618 nm) with -CNPPI: Ir(ppy)/Ir(MDQ) (acac) exhibits a maximum - 8823/38418 cd m; - 24.56/17.31%; - 84.30/18.09 cd A ; - 86.43/21.43 lm W with CIE (0.33, 0.61)/(0.65, 0.34).
一种新开发的策略用于构建具有与相同共轭菲并咪唑基团不对称连接的蓝色发光材料，该策略导致前线轨道的分离并形成供体-受体（D-A）结构。具有2-(萘-1-基)-1-(4-(1-(萘-1-基)-1-菲并[9,10-]咪唑-2-基)苯基)-1-菲并[9,10-]咪唑（-PPI）/2-(萘-1-基)-1-(3-(1-(萘-1-基)-1-菲并[9,10-]咪唑-2-基)苯基)-1-菲并[9,10-]咪唑（-PPI）发光层（-434/420 nm）的蓝色器件显示出高效率：电流效率（）-5.83/3.56 cd A；功率效率（）-5.73/3.48 lm W；在3.0 V时的外量子效率（）-8.98/6.48%。它们的氰基衍生物，-CNPPI/-CNPPI（-422/406 nm）在2.9 V时与-PPI/-PPI器件相比表现出最大效率（-6.28/4.38 cd A；-6.14/4.01 lm W；-9.01/6.72%）。D-A发射体中弱的电荷转移导致深蓝色发射。-PPI、-CNPPI、-PPI和-CNPPI的各向异性结构特征在薄膜中诱导了水平偶极取向并提高了电致发光效率。这些具有合适三线态能量的双极材料可用于绿色和红色磷光有机发光器件（PHOLEDs）中的主体材料。具有-CNPPI:Ir(ppy)/Ir(MDQ)(acac)的绿色/红色器件（-504/618 nm）表现出最大-8823/38418 cd m；-24.56/17.31%；-84.30/18.09 cd A；-86.43/21.43 lm W，色坐标为（0.33,0.61）/（0.65,0.34）。
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