Pendant Homopolymer and Copolymers as Solution-Processable Thermally Activated Delayed Fluorescence Materials for Organic Light-Emitting Diodes

Abstract

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Bridging Small Molecules to Conjugated Polymers: Efficient Thermally Activated Delayed Fluorescence with a Methyl‐Substituted Phenylene Linker

“…Thesecond one is directly using asmall molecular TADF unit, which is introduced into the main chain or side chain of ap olymeric host. [22][23][24][25] Unfortunately, the intrinsic low triplet energy,e specially for conjugated polymers,o ften leads to the loss of triplet excitons and thus poor device performance.…”

Recent Advances in Polymer Organic Light-Emitting Diodes (PLED) Using Non-conjugated Polymers as the Emitting Layer and Contrasting Them with Conjugated Counterparts

“…The best performing non-conjugated TADF polymer in this review is TADF-P2 with a device that gave an EQE of 20.1%, 21 yet it should be noted that the polymer was doped in a large amount (90 wt.%) of small-molecule mCP host as the emitting layer. On the other hand, neat TADF-P1 as the emitting layer gave a decent EQE of 10%.…”

“…78 A follow-up study by the same group investigated the impact of styrene content in a series of copolymers of styrene and PTZ-DBTO2 chromophore on their photophysical properties and device performance. 21 A homopolymer of PTZ-DBTO2 was also synthesized and studied. It was found that, with increasing styrene composition in the polymers, the contribution of the delayed fluorescence became more significant due to suppressed triplet-triplet annihilation (TTA) because the concentration of PTZ-DBTO2 chromophore in the polymer was diluted.…”

“…* In addition, the device based on crosslinked DV-CDBP (as host) and DV-MOS-DPS (as TADF chromophore) gave an EQE of 2.0% whereas TADF polymer TADF-P2 offered a much higher EQE of 20.1%. 21 One possible reason for the lower device efficiency is the very limited characterization and purification available for the resulting intractable cross-linked polymer film.…”

“…2b). [19][20][21] In this review, recent advances (mainly after 2010) in non-conjugated polymers employed as emitters in PLED devices will be discussed, where they can be divided into three main classes of materials: fluorescent, phosphorescent and thermally activated delayed fluorescent (TADF). Their synthetic parameters such as polymerization method and yield, molecular weight distribution and purity shall be contrasted with those of recently reported conjugated polymers (2011-present).…”