Enhancing Molecular Aggregations by Intermolecular Hydrogen Bonds to Develop Phosphorescent Emitters for High‐Performance Near‐Infrared OLEDs

• Published in: Advanced science Vol. 6; no. 7; pp. 1801930 - n/a
• Main Authors: Yang, Xiaolong, Guo, Haoran, Xu, Xianbin, Sun, Yuanhui, Zhou, Guijiang, Ma, Wei, Wu, Zhaoxin
• Format: Journal Article
• Language: English
• Published: Germany John Wiley & Sons, Inc 03-04-2019; John Wiley and Sons Inc; Wiley
• Subjects: Communication; Communications; Efficiency; Hydrogen bonds; Ligands; molecular aggregation; near‐infrared emission; organic light‐emitting devices; Pt(II) complexes; Single crystals; molecular aggregation; near‐infrared emission; organic light‐emitting devices; hydrogen bonds; Pt(II) complexes
• ISSN: 2198-3844; 2198-3844
• DOI: 10.1002/advs.201801930

Phosphorescent near‐infrared (NIR) organic light‐emitting devices (OLEDs) have drawn increasing attention for their promising applications in the fields such as photodynamic therapy and night‐vision readable displays. Here, three simple phosphorescent Pt(II) complexes are synthesized, and their intermolecular interactions are investigated in crystals and neat films by X‐ray single crystal diffraction and grazing‐incidence wide‐angle X‐ray scattering, respectively. The photophysical properties, molecular aggregation (including Pt–Pt interaction), molecular packing orientation, and electron transport ability are all influenced by the strong intermolecular hydrogen bonds. Consequently, the nondoped OLEDs based on tBu‐Pt and F‐Pt show electroluminescent emissions in NIR region with the highest external quantum efficiencies of 13.9% and 16.7%, respectively.
Because of enhanced molecular aggregations induced by strong intermolecular hydrogen bonds, a simple Pt(II) complex neat film shows near‐infrared (NIR) emission with high photoluminescence quantum yield, improved electron transport ability, and preferred molecular orientation. The related nondoped organic light‐emitting device (OLED) exhibits the near‐infrared (NIR) emission with a peak external quantum efficiency of 16.7%.