Synthesis of pyrene-cored dendrimers with 9-phenylcarbazole-based dendrons and their thermal, photophysical and electrochemical properties

The improvement in hole-transporting and electroluminescent properties of diketopyrrolopyrrole pigment by grafting with carbazole dendrons

Diketopyrrolopyrrole (DPP) pigments are essential and have been intensively exploited as building-blocks for the synthesis of organic semiconducting polymers and small molecules; however, DPP derivatives as emissive materials for electroluminescent (EL) devices have rarely been explored. In this work, a series of new DPP derivatives grafted with carbazole dendrons in a non-conjugated fashion using an amide linkage was designed to improve the performance of DPP in EL devices. Three DPP derivatives (G0DPP, G1DPP and G2DPP) bearing di(p-chlorophenyl)-DPP (Pigment Red 254) as the core substituted with a hexyl chain, N-hexyl carbazole and N-hexyl-N'-9,3':6',N''-tercarbazole, respectively, were synthesized to afford improved hole-transporting properties without affecting the photophysical and electronic properties of the DPP core. The synthesized DPP derivatives displayed an intense yellow fluorescence emission peaked at 536 nm with an absolute photoluminescence quantum yield close to unity in solution. The hole-transporting capability of molecules was improved when carbazole dendrons were incorporated, which increased with an increase in the generation of substituent carbazole dendrons in the order of G0DPP < G1DPP < G2DPP. Significantly, the use of G2DPP, showing the highest hole mobility, in an EL device yielded a strong and stable yellow emission peaked at 556 nm (CIE x, y color coordinates of (0.45, 0.53)) with a brightness of 3060 cd m-2, maximum luminous efficiency of 9.24 cd A-1 and a maximum EQE of 3.11%.

Enhancement of the electroluminescence properties of iridium-complexes by decorating the ligand with hole-transporting carbazole dendrons

Iridium-complexes decorating with carbazole dendrons exhibit an improved hole-transporting capability and OLED devices with brightness of 16 170 cd m⁻², maximum luminous efficiency of 13.59 cd A⁻¹ and maximum EQE of 4.36%.

A dendrimer consisting of a pyrene core and a 9-phenylcarbazole periphery as a multi-functional fluorescent probe for iodide, iron(III) and mercury(II)

A dendrimer (termed G2) containing pyrene as the core and 9-phenylcarbazole (PCZ) on the periphery is shown to be a multi-functional fluorescent probe for iodide, iron(III) and mercury(II). It serves as the fluorometric/colorimetric dual-channel probe for these ions. As a fluorometric probe, the fluorescence of G2 is quenched both by iodide and iron(III). After that, the fluorescence of G2 which has been added iodide will recover when added mercury(II); as a colorimetric probe, the color of G2 solution can turn to yellow only by iodide which will change from yellow to colorless again when adding mercury(II). The color change is sensitive and observed visually at 0.1 mM for iodide. G2 also is an electroactive precursor for preparation of fluorescent films via electropolymerization. The resulting films can be used as the fluorescent films to sense the ions. This is attributed to the presence of a large specific surface, highly cross-linked microstructures and enhanced π conjugation. The electropolymerized film has blue fluorescence with excitation/emission maxima at 365/460 nm. The limits of detection (LOD) of G2 for iodide, iron(III) and mercury(II) were calculated to be 9.3, 37.1 and 22.0 nM in solution and 5.1, 12.0 and 6.1 nM in films, respectively. The linear range is from 2 to 10 μM for G2 electropolymerized films. The detection range is from 2 to 400 μM for iron(III) and mercury(II). The detection range is from 2 to 130 μM for iodide. For a third application, G2 displays compelling sensing performance in environmental systems and in living roundworms. Graphical abstractAs schematic presentation, after adding iodide, the fluorescence of G2 is quenched and the color changes to yellow. When adding Hg²⁺ to G2-iodide, the fluorescence and color of G2 recover. Iron(III) can also quench G2, but the color does not change.

Supramolecular liquid crystalline dendrimers with a porphyrin core and functional carboxylic acid dendrons

Supramolecular dendrimers prepared via H-bonding between porphyrin core and bifunctionalised dendrons, incorporated in the periphery, display photoluminescence properties and self-assembly into smectic mesophase.

Synthesis and photophysical properties of triphenylamine-based multiply conjugated star-like molecules

Novel triphenylamine-based star-like molecules were synthesized and their photophysical properties in different solvents have been investigated.

Novel metallo-dendrimers containing various Ru core ligands and dendritic thiophene arms for photovoltaic applications

A polymer solar cell device containing an active layer of BTRu2G3 : PC70BM = 1 : 3 (by wt), i.e., the third generation of the bis-Ru-based dendritic complex BTRu2G3 showed the highest PCE value of 0.77%.

Copper-catalyzed N-arylation of azoles and diazoles using highly functionalized trivalent organobismuth reagents

The N-arylation of indoles, indazoles, pyrroles, and pyrazoles using highly functionalized trivalent arylbismuth reagents is reported.