Copolyfluorenes Containing Bipolar Groups: Synthesis and Application To Enhance Electroluminescence of MEH−PPV

2-(Naphthalen-2-yl-oxy)-N'-[2-(naphthalen-2-yl-oxy)acet-yl]acetohydrazide monohydrate

The title compound, C24H20N2O4·H2O, crystallizes with half a mol-ecule of 2-(naphthalen-2-yl-oxy)-N'-[2-(naphthalen-2-yl-oxy)acet-yl]acetohydrazide and half a water mol-ecule in the asymmetric unit. In the crystal, mol-ecules form planes parallel to (011). Two mol-ecules are connected by water mol-ecules via O-H⋯O and N-H⋯O hydrogen bonds.

Synthesis and chemosensory application of water-soluble polyfluorenes containing carboxylated groups

Detection of metal ions in aqueous solutions is a major issue for environmental protection. Conjugated polyelectrolytes showing high sensitivity and selectivity towards the detection of metal ions are highly desirable. We report a water-soluble polyfluorene containing carboxylated groups (P1), poly[9,9'-bis(3''-propanoate)fluoren-2,7-yl] sodium salt, which shows high recognition capability toward Cu(+) and Cu(2+). P1 was prepared via the hydrolysis of poly[9,9'-bis(tert-butyl-3''-propanoate)fluoren-2,7-yl] (P0) which was synthesized by Suzuki coupling polymerization. The photoluminescence (PL) spectra of P1 in aqueous solution are significantly quenched in the presence of Cu(+) and Cu(2+). P1 shows high selectivity and sensitivity toward Cu(+) and Cu(2+), with the Stern-Volmer constants (Ksv) being 3.5 × 10(6) and 5.78 × 10(6) M(-1), respectively. Moreover, the stoichiometric ratio of the P1 repeat unit to Cu(+) or Cu(2+) is 2 : 1 obtained from Job's plot. P1 maintains high selectivity towards Cu(+) or Cu(2+) in the presence of various metal cations. Our results demonstrate that P1 shows very high sensitivity and selectivity in recognizing Cu(+) and Cu(2+), indicating that it is a promising functional material for chemical sensors.

Solution-processable hole-transporting material containing fluorenyl core and triple-carbazolyl terminals: synthesis and application to enhancement of electroluminescence

A novel solution-processable, efficient hole-transporting material 2,4,7-tri[2-(9-hexylcarbazole)ethenyl]-9,9-dihexylfluorene (FC), composed of a fluorenyl core and triple-carbazolyl terminals, is successfully synthesized and well characterized. The FC is a thermally stable, amorphous material because of its aromatic and asymmetric structure. The highest occupied molecular orbital (HOMO) level of FC is -5.21 eV, as determined by cyclic voltammetry, implying its applicability as a hole-transporting layer (HTL) to promote hole injection. Furthermore, the FC could be deposited by a spin-coating process to obtain a homogeneous HTL film, more convenient and cost-effective than conventional NPB which must be deposited by vacuum vapor deposition. When fabricated as multi-layer OLED [ITO/PEDOT:PSS/HTL(25 nm)/Alq3(50 nm)/LiF(0.5 nm)/Al(100 nm)], the maximum brightness (21,400 cd m(-2)) and current efficiency (3.20 cd A(-1)) based on the FC are superior to those using conventional NPB as the hole-transporting layer. In addition, a homogeneous FC film is readily prepared by simple wet processes (spin-coating). Our results indicate that the FC is a promising optoelectronic material which is readily processed by wet methods such as spin-coating.

Water-soluble 1,2,4-triazole with diethylene glycol monoethyl ether groups: synthesis, characterization and application as an electron injection layer for PLEDs

A novel electron injection material 3OTAZ composed of an aromatic 1,2,4-triazolyl core with three diethylene glycol ether groups enhances electroluminescence of HY-PPV.