Copoly(p‐phenylene)s containing bipolar triphenylamine and 1,2,4‐triazole groups: Synthesis, optoelectronic properties, and applications

Abstract

Two novel copoly(p-phenylene)s (P1-P2) containing bipolar groups (12.8 and 6.8 mol %, respectively), directly linked hole transporting triphenylamine and electron transporting aromatic 1,2,4-triazole, were synthesized to enhance electroluminescence (EL) of poly(p-phenylene vinylene) (PPV) derivatives. The bipolar groups not only enhance thermal stability but also promote electron affinity and hole affinity of the resulting copoly(p-phenylene)s. Blending the bipolar copoly-(p-phenylene)s (P1-P2) with PPV derivatives (d6-PPV) as an emitting layer effectively improve the emission efficiency of its electroluminescent devices [indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene) (PEDOT):poly(styrenesulfonate) (PSS)/poly-mer blend/Ca (50 nm)/Al (100 nm)]. The maximum luminance and maximum luminance efficiency were significantly enhanced from 310 cd m À2 and 0.03 cd A À1 (d6-PPV-based device) to 1450 cd m À2 and 0.20 cd A À1 (blend device with d6-PPV/P1 ¼ 96/4 containing $0.5 wt % of bipolar groups), respectively. Our results demonstrate the efficacy of the copoly(p-phenylene)s with bipolar groups in enhancing EL of PPV derivatives. V C 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 5727-5736, 2010

Solution‐processable and thermally cross‐linkable fluorene‐cored triple‐triphenylamines with terminal vinyl groups to enhance electroluminescence of MEH‐PPV: Synthesis, curing, and optoelectronic properties

“…The turn‐on voltages are slightly increased to 3.6 V from 3.1 V of the device without cured‐ FTV layer. This is probably attributable to hole‐blocking effect of the cured‐ FTV layer that extra bias is needed to turn on the multilayer device 26. Moreover, maximum luminance and maximum current efficiency are enhanced from 1810 and 0.27 to 4640 cd/m 2 and 1.08 cd/A, respectively, by adding cured‐ FTV layer (film thickness: 55 ± 5 nm) (Fig.…”

Triple antiplatelet therapy with cilostazol: Hitting the “Sweet‐Spot”

“…In this study, difluoro bipolar monomer ( 9 ), with directly linked TPA and 1,2,4‐triazole as core, was used to synthesize bipolar copoly(aryl ether) ( P1 ). N ‐(4‐(3,5‐Bis(4‐fluorophenyl)‐4 H ‐1,2,4‐triazol‐4‐yl)phenyl)‐ N ‐phenylbenzenamine ( 9 ) and N ‐(4‐(3,5‐bis(4‐phenoxyphenyl)‐4 H ‐1,2,4‐triazol‐4‐yl) phenyl)‐ N ‐phenylbenzenamine ( M1 ) containing bipolar moieties were synthesized according to the synthetic routes outlined in Scheme 23(a), 28(b). The 1 H NMR spectra of P0 and P1 are shown in Supporting Information Figure.…”

“…Therefore, the development of emitting copolymers chemically bonded with both electron and hole injection/transport moieties is an ideal strategy in material design of PLEDs. Several research groups prepared copolymers carrying both electron‐ and hole‐transporting moieties in an attempt to improve their device performance 17–23. Song et al17(e) synthesized a copolymer containing both carbazole and oxadiazole units; it exhibited 36 times higher EL quantum efficiency as compared to PPV.…”

Poly(N‐isopropylacrylamide‐co‐N‐isopropylmethacrylamide) Thermo‐Responsive Microgels as Self‐Regulated Drug Delivery System

“…The diffusion rate is controlled mainly by the size and the porosity of the hydrogel. [25,26] Of course, hydrogels with micrometric dimensions and a high degree of porosity are characterized by fast swelling and deswelling rates. Moreover, since poly(NIPAAm-co-NIPMAAm) microgels are built by two similar co-monomers that individually hold very sharp phase transitions (see Figure 4), the phase transition of the copolymer seems to be even sharper than that of the homopolymers.…”