Jump to main content
Jump to site search

Issue 13, 2020
Previous Article Next Article

Rational design, synthesis, and characterization of a photocrosslinkable hole-transporting polymer for high performance solution-processed thermally activated delayed fluorescence OLEDs

Author affiliations

Abstract

A new photocrosslinkable hole-transporting homopolymer (PX2Cz) was successfully synthesized using 9-((3-methyloxetan-3-yl)methyl)-9′-(4-vinylbenzyl)-9H,9′H-3,3′-bicarbazole monomer via radical polymerization. Biscarbazole, as a hole-transporting material, has two reactive sites that can introduce a radical polymerizable styrene moiety and a photocrosslinkable oxetane moiety. The photocuring temperature and time for the PX2Cz film was optimized to be 120 °C and 10 s. The photocured films showed good solvent resistance, which is favorable for the deposition of an emitting-layer solution on them. In particular, the highest occupied molecular orbital (HOMO) energy of the as-cast PX2Cz film was determined to be −5.37 eV which remained unchanged even after photocuring, thus facilitating hole transportation from the hole-injection layer. Subsequently, solution-processed, green, thermally activated delayed fluorescent organic light-emitting diodes (TADF-OLEDs) were manufactured using PX2Cz as the hole-transport material. The devices displayed a notable performance with an exceptionally low turn-on voltage (Von) of only 2.8 V and a high external quantum efficiency (EQE) of 22.5%; these values are substantially better than those of commonly used poly(9-vinylcarbazole) (PVK)-based OLEDs (Von = 3.6 V, EQE of 15.5%). The remarkably low turn-on voltage and high EQE were ascribed to the shallower HOMO energy level and more pronounced hole-transport ability of the photocured PX2Cz film.

Graphical abstract: Rational design, synthesis, and characterization of a photocrosslinkable hole-transporting polymer for high performance solution-processed thermally activated delayed fluorescence OLEDs

Back to tab navigation

Supplementary files

Article information


Submitted
31 Dec 2019
Accepted
25 Feb 2020
First published
26 Feb 2020

J. Mater. Chem. C, 2020,8, 4572-4579
Article type
Paper

Rational design, synthesis, and characterization of a photocrosslinkable hole-transporting polymer for high performance solution-processed thermally activated delayed fluorescence OLEDs

J. H. Lee, C. H. Jeong, M. Godumala, C. Y. Kim, H. J. Kim, J. H. Hwang, Y. W. Kim, D. H. Choi, M. J. Cho and D. H. Choi, J. Mater. Chem. C, 2020, 8, 4572
DOI: 10.1039/C9TC07107E

Social activity

Search articles by author

Spotlight

Advertisements