Steric Switching for Thermally Activated Delayed Fluorescence by Controlling the Dihedral Angles between Donor and Acceptor in Organoboron Emitters
| Autor: | Min-Jie Huang, Chien-Hong Cheng, Shih-Han Lo, Tien-Lin Wu, Chang Yu-Che |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Steric effects
chemistry.chemical_classification Photoluminescence Materials science Carbazole 02 engineering and technology Electron acceptor Dihedral angle 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Acceptor Fluorescence 0104 chemical sciences chemistry.chemical_compound Crystallography chemistry OLED General Materials Science 0210 nano-technology |
| Zdroj: | ACS Applied Materials & Interfaces. 11:10768-10776 |
| ISSN: | 1944-8252 1944-8244 |
| DOI: | 10.1021/acsami.8b21568 |
| Popis: | Five emitters CzAZB, tBuCzAZB, tmCzAZB, dmAcAZB, and PxzAZB based on dibenzo-1,4-azaborine as the electron acceptors and two identical amine groups as the donors were designed and synthesized. The dihedral angles between the planes of dibenzo-1,4-azaborine acceptors and amine-based donors greatly affect the thermally activated delayed fluorescence (TADF) property of these materials. A simple concept "steric switching" is introduced to predict whether the emitter possesses TADF property. CzAZB and tBuCzAZB, with very high photoluminescence quantum yields (PLQYs) but small dihedral angles, do not show TADF. In contrast, tmCzAZB reveals a PLQY of only 56% but with a large dihedral angle due to the presence of two methyl groups at C1 and C8 of the carbazole groups, the steric switching operates, and the compound shows TADF property with a deep-blue color having CIE coordinates of (0.14, 0.15). In a similar manner, in dmAcAZB and PxzAZB with high PLQYs and large dihedral angles between the donor and acceptor planes, the "TADF steric switch" readily operates to achieve device external quantum efficiencies as high as 20.8 ± 1.2 and 27.5 ± 1.9% with blue and green emissions, respectively. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|