Department of Chemistry and Key Laboratory for, Preparation and Application of Ordered Structural Materials of, Guangdong Province, Shantou University, Guangdong, 515063, P.R. China.
Department of Physics, Fudan University, Shanghai, 200433, P.R. China.
Chemistry. 2018 Oct 17;24(58):15566-15571. doi: 10.1002/chem.201801822. Epub 2018 Sep 17.
A new ternary acceptor (A)-donor (D)-acceptor (A) asymmetrically twisted deep-blue emitting molecule, PPI-2BI, was synthesized by attaching two electrophilic benzimidazole (BI) units to the C2 and N1 positions of a phenanthroimidazole (PI) donor unit. Profiting from the enhanced D-A electronic coupling, the electron injecting and transporting abilities of the new triangle-shaped A-D-A molecule are considerably improved and the molecule shows high photoluminescence (PL) and electroluminescence (EL) efficiencies. By using PPI-2BI as a non-doped emitting layer (EML), the resulting organic light-emitting device exhibits emission with color coordinates of (0.158, 0.124) and a maximum external quantum efficiency (EQE), current efficiency (CE), and power efficiency (PE) of 4.63 %, 4.98 cd A , and 4.82 lm W , respectively. Additionally, a simple bilayer device using PPI-2BI as both the EML and the electron-transporting layer (ETL) also shows an EQE of 3.81 % with little changes to the color purity. Remarkably, a PPI-2BI-based doped device emits efficient near-ultraviolet EL with color coordinates of (0.154, 0.047) and an EQE of 4.12 %, which is comparable to that of the best reported near-UV emitting devices.
一种新型的三元受体（A）-给体（D）-受体（A）不对称扭曲的深蓝色发光分子，PPI-2BI，通过将两个亲电苯并咪唑（BI）单元连接到苯并咪唑（PI）供体单元的 C2 和 N1 位置来合成。得益于增强的 D-A 电子偶极矩，新的三角形 A-D-A 分子的电子注入和传输能力得到了显著提高，并且该分子表现出高光致发光（PL）和电致发光（EL）效率。通过使用 PPI-2BI 作为无掺杂发射层（EML），所得有机发光器件表现出（0.158，0.124）的发射色坐标和最大外量子效率（EQE）、电流效率（CE）和功率效率（PE）分别为 4.63%、4.98 cd A 和 4.82 lm W。此外，使用 PPI-2BI 作为 EML 和电子传输层（ETL）的简单双层器件也表现出 3.81%的 EQE，而色纯度几乎没有变化。值得注意的是，基于 PPI-2BI 的掺杂器件发出高效的近紫外 EL，其发射色坐标为（0.154，0.047），EQE 为 4.12%，与最佳报道的近紫外发射器件相当。
