Effect of dendrimer surface groups on the properties of phosphorescent emissive films

Twisted Carbazole Dendrons for Solution-Processable Green Emissive Phosphorescent Dendrimers

“…2,6-Bis[N-3,6-di-tert-butylcarbazolyl]toluene (6). 2,6-Dibromotoluene (1.00 g, 0.55 mL, 4 mmol), 3,6-di-tert-butyl-9H-carbazole (2.78 g, 9.9 mmol), copper(I) iodide (3.03 g, 15.9 mmol), 1,10phenanthroline (0.28 g, 1.57 mmol), and oven-dried potassium carbonate (4.33 g, 31.33 mmol) were added to a dry Schlenk tube under argon.…”

“…3−5 A further advantage of using light-emitting dendrimers is that not only is the emissive chromophore more soluble itself, but they can also be used to form good-quality thin films when blended with a host that is poorly soluble. 6 Furthermore, in some cases, it has been shown that light-emitting dendrimers can be used in host-free OLEDs with excellent efficiencies. 7−9 This is particularly the case when the emissive chromophore is at the core of the dendrimer.…”

“…The need to keep the molecular weight of the materials low for thermal evaporation means that many of the best OLED materials do not have sufficient solubility to be used for the fabrication of solution-processed OLEDs. A successful strategy for improving the solubility of emissive chromophores is to incorporate them into a dendritic architecture. , Both phosphorescent and, more recently, TADF emitters have been incorporated into dendrimeric structures. − A further advantage of using light-emitting dendrimers is that not only is the emissive chromophore more soluble itself, but they can also be used to form good-quality thin films when blended with a host that is poorly soluble . Furthermore, in some cases, it has been shown that light-emitting dendrimers can be used in host-free OLEDs with excellent efficiencies. − This is particularly the case when the emissive chromophore is at the core of the dendrimer.…”

Effect of dendrimer generation and surface groups on the optoelectronic properties of green emitting bis-tridentate iridium(iii) complexes designed for OLEDs

“…For example, neat films of the first-generation tris-bidentate iridium( iii ) dendrimer with the same first-generation dendrons and 2-ethylhexyloxy surface groups attached to the phenyl ring of the fac -tris[2-phenylpyridinato- C 2 , N ]iridium( iii ) (Ir(ppy) 3 ) complex core has been reported to have a hole mobility of around an order of magnitude higher at (4.0 ± 0.7) × 10 −6 cm 2 V −1 s −1 . 12 The lower charge mobility in the new series of dendrimers is likely to arise from the insulating dendrons encapsulating the cores in such a way as to decrease the hopping of charge from one core to the next in a neat film.…”

“…It has been previously shown that dendron generation, surface groups, and/or the number of dendrons attached to the complex can be used to control solubility and intermolecular interactions. [10][11][12][13] In addition, dendrons composed of charge transport 14,15 or insulating units 16 have been reported, although in most cases the charge is transported via core-to-core hopping in neat films as the iridium(III) complex often has the smaller (relative to the dendron) redox potentials. However, one of the issues with attaching dendrons to bidentate ligands is that the dendrons are always pointing away from the central iridium(III) atom.…”