All-Solution-Processed Multilayered White Polymer Light-Emitting Diodes (WPLEDs) Based on Cross-Linked [Ir(4-vb-PBI)(acac)].

All-solution-processed multilayered white polymer light-emitting diodes (WPLEDs) are promising candidates for low-cost and large-area flexible full-color flat-panel displays and solid-state lighting. However, it is still challenging to improve their performance. In this work, based on an elegant strategy of orthogonal materials, the utilization of the cross-linked Ir polymer film ( = -vinyl-carbazole; = 1-(4-vinylbenzyl)-2-phenyl-1-benzo[]imidazole; and = acetylacetone) as the emitting layer (EML) between a hydrophilic polymer film poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) () as the hole injection layer (HIL) and a hydrophobic polymer film ( = 2-(4-(-butyl)phenyl)-5-(4'-vinyl-[1,1'-biphenyl]-4-yl)-2,5-dihydro-1,3,4-oxadiazole) as the electron transport layer (ETL) led to the successful fabrication of reliable all-solution-processed multilayered WPLEDs.

Efficient white polymer light-emitting diodes (WPLEDs) based on covalent-grafting of into PVK.

Thanks to the straightforward white light of single grafting-type polymers based on earth-abundant Zn(ii)-complexes, producing cost-effective flexible WOLEDs/WPLEDs with good device performance remains a formidable challenge. Herein, by using the polymer with excellent physical properties for single-layer WPLEDs, record-high efficiencies ( = 13.0 cd A, = 6.

Temperature-dependent self-assembly of near-infrared (NIR) luminescent Zn2Ln and Zn2Ln3 (Ln=Nd, Yb or Er) complexes from the flexible Salen-type Schiff-base ligand.

Through the self-assembly of the precursor [Zn(L)(MeCN)] (H2L=N,N'-bis(3-methoxy-salicylidene)cyclohexane-1,2-diamine) with LnCl3·6H2O (Ln=La, Nd, Yb, Er or Gd) and NaN3 in alcohol-containing solutions, two series of mixed anions-induced Zn2Ln-arrayed complexes [Zn2(L)2(MeOH)ClLn(N3)]·Cl (Ln=La, 1; Ln=Nd, 2; Ln=Yb, 3; Ln=Er, 4 or Ln=Gd, 5) and Zn2Ln3-arrayed complexes [Zn2(L)3Cl2(μ2-OH)(μ3-OH)2Ln3(N3)2] (Ln=La, 6; Ln=Nd, 7; Ln=Yb, 8; Ln=Er, 9 or Ln=Gd, 10) are obtained at room temperature or under reflux, respectively. In contrast to Zn2Ln-arrayed complexes with the two Zn2+ ions in the inner cis-N2O2 cores and one Ln3+ ion in the outer O2O2 moieties, the demetalation of partial precursors leads to the selective exchange of Zn2+ centers for the Ln3+ ions for the formation of novel heterometallic Zn2Ln3-arrayed complexes with the Ln3+ ions in both the inner cis-N2O2 core and the outer O2O2 moieties of the ligands. The result of their photophysical properties shows that the characteristic near-infrared (NIR) luminescence of Nd3+ or Yb3+ ion has been sensitized from the excited state (both 1LC and 3LC) of the ligand H2L, while relatively lower quantum yields for Zn2Ln3-arrayed complexes than those for Zn2Ln-arrayed complexes, correspondingly, should be due to the luminescent quenching with the involvement of OH- oscillators around the Ln3+ ions.

Near-infrared (NIR) luminescent hetero-tetranuclear Zn2Ln2 (Ln = Nd, Yb or Er) complexes self-assembled from the benzimidazole-based HL and two rigid 4,4'-bipyridine ligands with different spacers.

Through the self-assembly of the benzimidazole-based ligand HL (HL=2-(1H-benzo[d]imidazol-2-yl)-6-methoxyphenol) with Zn(OAc)2 · 2H2O, Ln(NO3)3·6H2O (Ln=Nd, Yb, Er or Gd) and 4,4'-bipyridine ligand (bpy, 4,4'-bipyridine or bpe, trans-bis(4-pyridyl)ethylene), two series of Zn2Ln2-arrayed complexes [Zn(2)Ln(2)(L)4(bpy)(NO3)6] (Ln=Nd, 1; Yb, 2; Er, 3 or Gd, 4) and [Zn(2)Ln(2)(L)4(bpe)(NO3)6] (Ln=Nd, 5; Yb, 6; Er, 7 or Gd, 8) were obtained, respectively. The result of their photophysical properties shows that the characteristic near-infrared (NIR) luminescence of Nd(3+), Yb(3+) or Er(3+) ion has been sensitized from the excited state (both (1)LC and (3)LC) of the mixed HL and bipyridyl ligands in both complexes 1-3 and 5-7. Moreover, the change from bpy to bpe bridging for the fine-tuning of whole molecular conjugations, attributing to the different crossings of the two benzimidazole-based L(-) ligands, has the important influence on their NIR luminescent properties.