Synthesis, Properties, and Application of New Luminescent Polymers with Both Hole and Electron Injection Abilities for Light-Emitting Devices

Abstract

New luminescent polymers that contain both electron-withdrawing cyano groups and electron-rich moieties, triphenylamine (TPA) or tetraphenyldiaminobiphenyl (TPD), were synthesized by Knoevenagel condensation of 1,4-bis(cyanomethyl)-2-[(2-ethylhexyl)oxy]-5-methoxybenzene with the dialdehyde of TPA or TPD, respectively. The polymers were characterized by NMR, FT-IR, microanalysis, GPC, DSC, and TGA. Efficient orange photoluminescence was observed with an absolute quantum efficiency of 48% for the TPA incorporated polymer (TPA-CNPPV). Cyclic voltammetry investigation showed that the polymers presented reversible oxidation and reduction with relatively low potentials, which suggested that the polymers have both good electron and hole injection abilities. We demonstrated an effective approach to synthesize polymers with the triad properties of efficient photoluminescence, good hole injection and high electron-affinity properties, which are highly desirable for application in light-emitting devices. This point was supported by the demonstration of a single layer light-emitting device with a configuration of ITO/TPA-CNPPV/Al, in which good external quantum efficiency (0.1%) and bright luminance of 2100 cd/m2 was achieved. Multilayer LEDs using the polymers as the active layers and different charge injection/transporting layers were also investigated.

Selective Tuning of the HOMO–LUMO Gap of Carbazole‐Based Donor–Acceptor–Donor Compounds toward Different Emission Colors

“…Compounds 3 and 4 both undergo remarkably reversible oxidation and reduction processes, suggesting their potential use for bipolar charge transport properties. [29] This is also supported by the following theoretical results. To provide further evidence for the observed electronic properties of these compounds, theoretical calculations were carried out with the Gaussian 03 packages [30] on an NK Star Supercomputer by using the B3LYP/6-31G(d)// www.eurjoc.org AM1/AM1 model, which was shown to be capable of accurately evaluating the ionization potentials (a property of the HOMO) of polysubstituted aromatics.…”

A Binaphthyl-Bithiophene Copolymer for Light-Emitting Devices

“…[1 -11] In a previous work, we have demonstrated an efficient light-emitting diode (LED) using a 1,19-binaphthyl-derived polymer (PHBN, as shown in Figure 1) as an emissive material. [12] A double layer LED with a configuration of ITO/PHBN/FCuPc/Al, in which ITO is indium tin oxide and FCuPc was copper (II) 1,2,3,4,8,9,10,11,15,16,17,18,22,23,24,25-hexadecafluoro-29H,31H-phthalocyanine, showed a high brightness (9 400 cd N m -2 at 24.3 mA N cm -2 ), a high luminous efficiency (4.9 lm N W -1 ), and a large external quantum efficiency (2.0%). It was known that the 1,19-binaphthyl unit possesses a large dihedral angle ranging from 60 8 to 120 8.…”

Synthesis, Photophysical and Electrochemical Properties of Novel Conjugated Donor-Acceptor Molecules Based on Phenothiazine and Benzimidazole

“…Phenothiazine-3-carbaldehyde and phenothiazine-3,7-dicarbaldehyde were synthesized using Vilsmeier-Haak reaction. 19 The 1 H and 13 C NMR spectra were collected on Jeol JNM-AL300 spectrometer at 300 MHz and 75 MHz, respectively. HRMS spectra were recorded on Jeol JMS-700 spectrometer.…”