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Type: Journal article
Title: Twisted Carbazole Dendrons for Solution-Processable Green Emissive Phosphorescent Dendrimers.
Author: Howell, S.A.
Koodalingam, M.
Jang, J.
Ranasinghe, C.S.K.
Gao, M.
Chu, R.
Babazadeh, M.
Huang, D.M.
Burn, P.L.
Shaw, P.E.
Puttock, E.V.
Citation: ACS Applied Materials and Interfaces, 2023; 15(10):13393-13404
Publisher: American Chemical Society (ACS)
Issue Date: 2023
ISSN: 1944-8244
Statement of
Sidney A. Howell, Manikandan Koodalingam, Junhyuk Jang, Chandana Sampath Kumara Ranasinghe, Mile Gao, Ronan Chu, Mohammad Babazadeh, David M. Huang, Paul L. Burn, Paul E. Shaw, and Emma V. Puttock
Abstract: A family of first-generation dendrimers containing 3,5-bis(carbazolyl)phenyl dendrons attached to a green emissive fac-tris(2-phenylpyridyl)iridium(III) core were prepared. The solubility of the dendrimers was imparted by the attachment of tert-butyl surface groups to the carbazole moieties. The dendrimers differed in the number of dendrons attached to each ligand (one or two dendrons) as well as the degree of rotational restriction within the dendrons. The densities of the films containing the doubly dendronized materials were higher than those of their mono-dendronized counterparts, with the dendrimer containing two rotationally constrained dendrons per ligand having the highest density at 1.12 ± 0.04 g cm-3. The dendrimers were found to have high photoluminescence quantum yields (PLQYs) in solution of between 80 and 90%, with the doubly dendronized materials having the lower values and a red-shifted emission. The neat film PLQY values of the dendrimers were less than those measured in solution although the relative decrease was smaller for the doubly dendronized materials. The dendrimers were incorporated into solution-processed bilayer organic light-emitting diodes (OLEDs) composed of neat or blend emissive layers and an electron transport layer. The best-performing devices had the dendrimers blended with a host material and external quantum efficiencies as high as 14.0%, which is higher than previously reported results for carbazole-incorporating emissive dendrimers. A feature of the devices containing blends of the doubly dendronized materials was that the maximum efficiency was relatively insensitive to the concentration in the host between 1 and 7 mol %.
Keywords: carbazole dendrons
charge transport
film density
light-emitting dendrimer
organic light-emitting diodes
Rights: © 2023 American Chemical Society
DOI: 10.1021/acsami.2c22990
Grant ID:
Appears in Collections:Physics publications

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