Development of suitable host materials for application to an emitter is of significant importance for the high-efficiency organic light-emitting diodes (OLEDs). In this study, we successfully synthesized poly(9,9-diphenyl-10-(4-vinylbenzyl)-9,10-dihydroacridine) (P(Bn-DPAc)) as...

Recently, various hosts and emitters for solution-processable thermally activated delayed fluorescence organic lightemitting diodes (TADF-OLEDs) have been developed. However, a few studies have been conducted on hole transport materials (HTMs) with differentiated solubility characteristics for manufacturing multilayer OLEDs using a solution process. Here, three new hole transport (HT) styrene polymers, PICz, PPBCz, and PTPCz, were synthesized by radical polymerization. Each of the polymers exhibited increases in their highest occupied molecular orbital (HOMO) levels and better hole-transporting abilities than poly(9vinylcarbazole) (PVK) as a reference HT polymer. Furthermore, the three HT polymers exhibited different solubilities in toluene. Therefore, it was not possible to use a toluene solution to prepare the emitting layer (EML). To overcome this problem, ethyl acetate (EA), in which the three HT polymers are insoluble, was used as an orthogonal solvent to prepare an EML solution. In EAsolution-processed green-emitting TADF-OLEDs, the three HT-polymer-based devices displayed somewhat low turn-on voltages of 2.8 V and high external quantum efficiencies (EQEs) of >23%. These values are superior to those of a device with a PVK-HT layer. In addition, the devices manufactured with the EA solution showed high-performance reproducibility owing to the stable formation of each layer. In this study, we removed the HTM solubility constraint by dramatically changing the solvent for preparing the EML solution and provided an efficient strategy for the fabrication of OLED devices via solution processes in the future.

Recently, conjugated donor–acceptor block copolymers (CDABPs) were synthesized by one-pot polymerization and applied in polymer solar cells with a single-component active layer. These polymers can suppress phase separation and exhibit...

In this study, we synthesized three novel aromatic imide-based conjugated donor­(D)-σ-acceptor (A) dyad-based polymers showing different photophysical properties. These D-σ-A dyad-based polymers (e.g., BDTBT-NI, BDTBT-NDI, and BDTBT-PDI) consist of the same conjugated donor main chains (benzodithiophene-bithiophene (BDTBT)) and side chains bearing different imide acceptors (naphthalimide (NI), naphthalene diimide (NDI), or perylenediimide (PDI)). The photophysical and electrochemical characteristics of the three polymers were studied using various methods, including UV–visible absorption, steady-state fluorescence, and time-resolved fluorescence experiments as well as cyclic voltammetry. As the acceptor strength of the side chain was increased, photoinduced electron transfer from the donor backbone to the acceptor side-chain moiety was found to occur more effectively. Among the three polymers, BDTBT-PDI was found to be used as an efficient extractor and portable naked-eye sensing probe for Fe2+ ions; notably, it exhibited a “turn-on” fluorescence response with a detection limit at a picomolar concentration. The BDTBT-PDI:Fe2+ complex was also used for ultrasensitive detection of spermine (with a Stern–Volmer constant of 6.7 × 106 M–1) in urine samples and was established as an efficient portable test kit for the real-time detection of spermine in the vapor released from fermented food samples. Finally, the “on–off” fluorescence behavior of BDTBT-PDI in the presence of Fe2+ and spermine enabled us to develop molecular logic gates using this polymer.

Herein, a novel hole transport polymer, P-CzAc, for solution-processed green quantum dot light-emitting diodes (QD-LEDs) was synthesized. P-CzAc consists of a polystyrene backbone and 10-(9H-carbazol-3-yl)-9,9-dimethyl-9,10-dihydroacridine as side-chain pendants. The design...