Jianhua Guo

High-performance blue electroluminescent devices based on hydroxyphenyl-pyridine beryllium complex

Blue light organic electroluminescent (EL) devices with high-performance were fabricated by using a highly fluorescent material, bis[2-(2-hydroxyphenyl)-pyridine]beryllium (Bepp2). The double layer devices with a structure of [indium tin oxide/N, N′-di(α-naphthyl)-N-N′-diphenyl(1, 1′-biphenyl)-4, 4′-diamine (600u200aA)/Bepp2 (500 A)/LiF (10 A)/Al (2000 A)] exhibited a maximum luminance of 15u200a000 cd/m2 and a maximum electroluminescent efficiency of 3.43 lm/w (3.8 cd/A).

Construction of full-color-tunable and strongly emissive materials by functionalizing a boron-chelate four-ring-fused π-conjugated core

2-(2′-Hydroxyphenyl)benzoxazole (HBO) and 2-(2′-hydroxyphenyl)benzothiazole (HBT) reacted with triphenylborane produced two rigid π-conjugated fluorescent cores 1 (BPh2(BOZ), BOZ = 2-(benzo[d]oxazol-2-yl)phenol) and 2 (BPh2(BTZ), BTZ = 2-(benzo[d]thiazol-2-yl)phenol). Comparisons of photophysical properties and calculations between para- and meta-diphenylamine-substituted derivatives 5 (BPh2(para-NPh2-BTZ)) and 7 (BPh2(meta-NPh2-BTZ)) demonstrated that functionalization at the para-position of the rigid core is effective in tuning the electronic structure and hence the photophysical properties of this type of boron-chelate complex. Simple modification of these frameworks by introducing various amine groups at the para-position allows the synthesis of strongly fluorescent materials 3 (BPh2(para-Cz-BTZ), Cz = 9H-carbazol-9-yl), 4 (BPh2(para-NPh2-BOZ), NPh2 = diphenylamino), 5, and 6 (BPh2(para-NMe2-BTZ), NMe2 = dimethylamino). The emission colors of these newly synthesized complexes together with the parent complexes 1 and 2 covered a wide range from deep blue to saturated red in both solution and the solid state. Crystal structure analysis discloses that two phenyl groups attached to the boron atom effectively keep the luminescent ring-fused π-conjugated skeletons apart, making these fluorophores highly emissive in solid forms (ΦF = 0.36–0.71). Organic light-emitting diodes employing these boron complexes as emitters not only keep the full-color tunable emission feature but also show high electroluminescent (EL) performance; for instance, the greenish-blue device based on 2 showed the highest efficiency of 7.8 cd A−1 and the yellow light-emitting device based on 4 exhibited the highest brightness (31u2006220 cd m−2) among the boron-containing emitters reported so far.

Hydroxyphenyl-benzothiazole based full color organic emitting materials generated by facile molecular modification

Two sets of hydroxyphenyl-benzothiazole based compounds, which exhibited emission colors across the entire visible spectrum for both photoluminescence and electroluminescence, have been designed and synthesized.

Photoluminescent and electroluminescent properties of phenol-pyridine beryllium and carbonyl polypyridyl Re(I) complexes codeposited films

Abstract The codeposited films of BePP 2 (PP=2-(2-hydroxyphenyl)-pyridine) and (Bu t bpy)Re(CO) 3 Cl (Bu t bpy=4,4′-bi( tert -butyl)-2,2′-bipyridine) were prepared by vacuum evaporation deposition. The photoluminescent and electroluminescent properties of the films were investigated. The films with different (Bu t bpy)Re(CO) 3 Cl concentration were employed to study the energy transfer properties between BePP 2 and (Bu t bpy)Re(CO) 3 Cl. Experimental results showed that energy transfer from BePP 2 to (Bu t bpy)Re(CO) 3 Cl took place in the codeposited films. The films which were excited optically, exhibited complete energy transfer if (Bu t bpy)Re(CO) 3 Cl concentrations were equal or higher than 9%. Under electrical excitation, complete energy transfer were observed when (Bu t bpy)Re(CO) 3 Cl concentrations were equal or higher than 3%. The devices of (ITO/TPD (500xa0A)/BePP 2 :(Bu t bpy)Re(CO) 3 Cl (500xa0A)/Al (2000xa0A)) which contained the codeposited film with (Bu t bpy)Re(CO) 3 Cl concentration of 50%, showed maximum EL efficiency value of 1.6xa0lm/W and maximum lightness of 6500xa0cd/m 2 .

[meso-Tetrakis(pentafluorophenyl)porphyrinato]platinum(II) as an efficient, oxidation-resistant red phosphor: spectroscopic properties and applications in organic light-emitting diodes

[meso-Tetrakis(pentafluorophenyl)porphyrinato]platinum(II) n(PtF20TPP) exhibits strong red phosphorescence and high stability with respect to oxidative degradation. OLEDs affording efficient saturated red emission have been fabricated using the PtF20TPP dopant.

Quinoacridine derivatives with one-dimensional aggregation-induced red emission property.

A new series of acceptor-donor-acceptor (A-D-A) type quinoacridine derivatives (1-3) with aggregation-induced red emission properties were designed and synthesized. In these compounds, the electron-withdrawing 2-(3,5-bis(trifluoromethyl)phenyl)acetonitrile groups act as electron-accepting units, while the alkyl-substituted conjugated core acts as electron-donating units. The restriction of intramolecular rotation was responsible for the AIE behavior of compounds 1-3. All compounds were employed as building blocks to fabricate one-dimensional (1-D) organic luminescent nano- or microwires based on reprecipitation or slow evaporation approaches. Morphological transition from zero-dimensional (0-D) hollow nanospheres to 1-D nanotubes has been observed by recording SEM and TEM images of aggregated sates of compound 2 in THF/H(2)O mixtures at different aging time. It was demonstrated that the synthesized compounds with different lengths of alkyl chains displayed different wire formation properties. The single-crystal X-ray analysis of compound 2 provided reasonable explanation for the formation of 1-D nano- or microstructures.

Red electroluminescent devices based on a porphyrin metal complex

A red luminescent tetra(naphthyl)porphyrin platinum(II) ( PtTNP ) was synthesized as an electroluminescent material. The photoluminescent and electroluminescent properties of PtTNP were investigated. PtTNP exhibits strong red photoluminance at 655 nm in solution. In this paper we report that PtTNP can be used as an emitting material to fabricate electroluminescent devices. PtTNP shows red electroluminescent emission at 655 nm with maximum efficiency of 1.47 cd/A.

CCDC 837275: Experimental Crystal Structure Determination

Related Article: Di Li, Hongyu Zhang, Chenguang Wang, Shuo Huang, Jianhua Guo, Yue Wang|2012|J.Mater.Chem.|22|4319|doi:10.1039/c1jm14606h