Twisted dendrons for highly luminescent green emissive phosphorescent dendrimers. Issue 38 (13th September 2018)

• Record Type: Journal Article
• Authors: Stoltzfus, Dani M.; Jiang, Wei; Brewer, Anthony M.; Burn, Paul L.
• Is Part Of: Journal of materials chemistry. Volume 6:Issue 38(2018)
• Page Start: 10315
• Page End: 10326
• Publication Date: 2018-09-13
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Optical materials -- Research -- Periodicals; Electronics -- Materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c8tc03491e
• Languages: English
• ISSNs: 2050-7526

Abstract

Abstract : A new class of twisted rigid biphenyl-based dendrons with t -butyl surface groups have been prepared and attached to a green emissive fac -tris(2-phenylpyridyl)iridium(iii ) core. Abstract : A new class of twisted rigid biphenyl-based dendrons with t -butyl surface groups have been prepared and attached to a green emissive fac -tris(2-phenylpyridyl)iridium(iii ) core. Both singly (one dendron per ligand) and doubly (two dendrons per ligand) dendronised first generation dendrimers were prepared. In both cases the solution photoluminescence quantum yields (PLQYs) were over 10% higher than the equivalent dendrimers comprised of non-rigid biphenyl-dendrons and the same core, with the doubly dendronised compound having an almost quantitative PLQY. However, for both materials there was significant reduction in the PLQY in the solid-state indicating that while the t -butyl groups can provide a degree of solubility they do not shield the emissive core as well as surface groups such as 2-ethylhexyloxy, which have greater length. When the doubly dendronised material was blended with 4, 4′, 4′′-tris(carbazol-9-yl)triphenylamine the film PLQY approached that of the solution measurement and simple two-layer devices comprised of the emissive layer and an electron transport/hole-blocking layer of 1, 3, 5-tris(3-pyridyl-3-phenyl)benzene reached a maximum brightness of ≈10 000 cd m −2 and external quantum efficiency of 16.3%, corresponding to an out-coupling efficiency of around 20%.