Synthesis and Electroluminescence of a Conjugated Polymer with Thermally Activated Delayed Fluorescence

Abstract

Scheme 1. Polymer Structures a a LKey: (a) General D-A type conjugated polymers, in which donors and acceptors are connected to each other in the backbone, resulting in large overlap between the HOMO and LUMO. (b) Designed conjugated polymers in which only donors are fixed in the backbone and acceptors are grafted in the side-chain. The HOMO and LUMO are sufficiently spatially separated to obtain a small ΔE ST . (c) Polymer structures of PAPCC and PAPTC. Note pubs.acs.org/Macromolecules

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

“…To our knowledge this is the highest EQE reported to date for a TADF polymer. [26][27][28][29][30][31] Furthermore, at 100 cd m -2 the EQE was 5.3%. High EQE, even at very low luminance, is widely recognized as an important figure-of-merit for OLED efficiencies.…”

“…Copo1 has very similar oxidation and reduction potentials to unsubstituted phenothiazine donor and dibenzothiophene-S,S-dioxide acceptor units, respectively. 30 All the polymers display similar oxidation and reduction behavior as the process is centered on the PTZ-DBTO2 TADF units.…”

“…The polymer showed EQE max of 10% at very low current densities and green emission with EQE >4.5% at 100 cd m -2 . Yang et al 28 synthesized copolymers from three monomer components, with a backbone of polycarbazole and 10-(4- 30 We identified the donor-acceptor (D-A) structure 2-(10H-phenothiazin-10-yl)dibenzothiophene-S,S-dioxide (PTZ-DBTO2) as an efficient TADF unit and recently reported preliminary data on the incorporation of this unit into polymeric structures. 31 OLEDs fabricated with a conjugated copolymer based on PTZ-DBTO2 and dibenzothiophene blocks as the active layer achieved EQE max 11.05% and 3.5% at 100 cd m -2 .…”

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

“…Thefirst one is based on the combination of an electron donor (D) and electron acceptor (A). [16][17][18][19][20][21] That is,both Dand Aare carefully aligned at different sites to form aT ADF polymer,s uch as Da nd A simultaneously in the main chain, [16] Dand Asimultaneously in the side-chain, [17,18] or Di nt he main chain and Ai nt he side-chain [19][20][21] etc. Unlike small molecules,i ti sn ot an easy task to realize TADF at am acromolecular level because the relative distance,strength, and location of Dand Aall need to be well controlled to tune through-bond or through-space charge transfer (CT).…”

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

“…77 Intuitively, TADF polymers should be based on a non-conjugated backbone to prevent triplet trap formation as triplet energy has been known to decrease rapidly with increasing effective conjugation length. 79,82 However, there have been several reports of conjugated TADF polymers with chromophores either grafted 83,84 or built-in along the polymer main-chain [85][86][87], and most of them performed nicely in PLED devices (EQE: 2.2-16.1%). Wei et al recently demonstrated how a TADF-inactive carbazole-based monomer could be turned into a TADF-active macromolecule (macrocycle or polymer).…”