New Design Tactics in OLEDs Using Functionalized 2‐Phenylpyridine‐Type Cyclometalates of Iridium(III) and Platinum(II)

Abstract

As a result of their outstanding attributes, organic light-emitting diodes (OLEDs) and white organic light-emitting diodes (WOLEDs) have been recognized in recent years as the most promising candidates for future flat-panel display technologies and next generation solid-state energy-saving lighting sources. New advancements in the area of high performance triplet emitters become vital for realizing more practical applications. In this regard, several critical issues must be carefully identified and addressed, and these include the ways to enhance device efficiency and suppress efficiency roll-off, to achieve versatile color tuning and simple device manufacture, as well as to obtain high-quality white light from WOLEDs. It has been shown that some functionalized phosphorescent Ir(III) and Pt(II) ppy-type cyclometalated complexes (ppy = 2-phenylpyridine) possess unique features that are suitable for solving these difficult and challenging tasks. In this Focus Review, we will highlight the recent design tactics adopted for these functional metallophosphors and the critical roles they may play in developing more realistic devices.

Pt(II) Phosphors Featuring Both Dicarbene and Functional Biazolate Chelates: Synthesis, Luminescent Properties, and Applications in Organic Light-Emitting Diodes

“…XXXX, XXX, XXX−XXX These complexes are essentially nonemissive in solution; however, the corresponding neat powder showed improved emission efficiency, except for the bipz 2− and bitz 2− substituted complexes 2 and 4, for which their propylene spacer resulted in a perpendicularly arranged dicarbene that destabilized the emitting excited state and seriously quenched the emission. Both DFT and TD-DFT calculations revealed the combined3 LLCT/ 3 LMCT/ 3 IL characters in the triplet excited states, which are in sharp contrast to the typical electronic transitions that involved the mixed 3 IL ππ* and 3 MLCT characters. The OLED device with a doped architecture afforded sky blue emission with high efficiencies (8.9%, 19.4 cd·A −1 , and 22.5 lm· W −1 ).…”

Synthesis and characterization of novel rhenium (I) complexes with large Stokes shift for applications in organic electroluminescent devices

“…Organic light-emitting diodes (OLEDs) possess latent application prospects in eco-friendly flat-panel displays and energy-saving solid-state lightings owing to rapid progress in material design and device fabrication [1][2][3][4][5][6][7][8]. Of the light-emitting organic materials available, phosphorescent materials are particularly captivating because they can harvest light from both singlet and triplet excitons, enabling the devices with close to 100% internal quantum efficiency.…”

Metal‐free cross‐dehydrogenative coupling approach for C‐H bond functionalization of 2‐phenyl pyridine derivatives in water

“…2‐phenyl pyridines are suitable substrates for the formation of cyclometalated complexes, a key step for the development of catalysts for well‐known Heck, Suzuki and Stille coupling reactions [8]. In addition, highly functionalized 2‐phenylpyridine cyclometalated complexes possess unique photophysical features that are suitable for more practical applications of organic light‐emitting diodes (OLEDs) [9]. Generally, the electron‐deficient property of pyridine ring is responsible for its low reactivity and usually requires N ‐activation for coupling under metal‐free conditions.…”