School of Chemistry and Biochemistry & Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, USA.
Phys Chem Chem Phys. 2013 May 7;15(17):6293-302. doi: 10.1039/c3cp50631b.
The development and application of phosphorescent emitters in organic light-emitting diodes (OLEDs) have played a critical role in the push to commercialization of OLED-based display and lighting technologies. Here, we use density functional theory methods to study how modifying the ancillary ligand influences the electronic and photophysical properties of heteroleptic bis(4,6-difluorophenyl) pyridinato-N,C [dfppy] iridium(III) complexes. We examine three families of bidentate ancillary ligands based on acetylacetonate, picolinate, and pyridylpyrazolate. It is found that the frontier molecular orbitals of the heteroleptic complexes can be substantially modulated both as a function of the bidentate ligand family and of the substitution patterns within a family. As a consequence, considerable control over the first absorption and phosphorescence emission transitions, both of which are dominated by one-electron transitions between the HOMO and LUMO, is obtained. Tuning the nature of the ancillary ligand, therefore, can be used to readily modulate the photophysical properties of the emitters, providing a powerful tool in the design of the emitter architecture.
磷光发射器在有机发光二极管（OLED）中的发展和应用在推动基于 OLED 的显示和照明技术商业化方面发挥了关键作用。在这里，我们使用密度泛函理论方法研究了修饰辅助配体如何影响杂双（4,6-二氟苯基）吡啶并-N,C [dfppy] 铱（III）配合物的电子和光物理性质。我们研究了基于乙酰丙酮酸盐、邻苯二甲酸盐和吡啶吡唑酸盐的三种双齿辅助配体家族。结果发现，杂配合物的前沿分子轨道可以根据双齿配体家族以及家族内的取代模式在很大程度上进行调节。因此，可以对第一吸收和磷光发射跃迁进行相当大的控制，这两个跃迁都由 HOMO 和 LUMO 之间的单电子跃迁主导。因此，调节辅助配体的性质可以用来轻松调节发射器的光物理性质，为发射器结构的设计提供了一个强大的工具。
