The establishment of conducting network in a polymer matrix is essential for the improvement in electrical conductivity and electromagnetic interference (EMI) shielding performance. Here, we report ...the fabrication of nanocomposites comprising polyamideimide and multiwalled carbon nanotubes (MWCNTs) (from 0.5 to 5.0 wt%). The effect of MWCNTs on electrical conductivity, morphology, and EMI shielding behavior has been examined. The morphology of nanocomposites was investigated by scanning electron microscope and x‐ray diffraction, which confirms the uniform dispersion of MWCNTs in the matrix. The electrical conductivity increases from 1.4 × 10−12 to 0.145 × 10−4 S/cm by the inclusion of MWCNTs. The composite PACNT‐5 exhibits a good EMI shielding efficiency of −17 dB in the X‐band region by employing only 5.0 wt% of MWCNTs. The incorporation of MWCNTs formed an interconnected conducting network, which boost the transferability of electrons or charge carriers. This work demonstrates a feasible, simple, and effective strategy for the fabrication of potential PAI/MWCNT composites for highly efficient EMI shielding materials.
A series of lanthanide complexes have been synthesized with fluorinated 1,3-diketones and heteroaromatic ancillary moieties. Spectroscopic studies reveal the attachment of the respective lanthanide ...ion to the oxygen site of β-diketone and nitrogen site of auxiliary moieties. The conducting behavior of the complexes is proposed by their optical energy gaps which lie in the range of semiconductors. The emission profiles of the lanthanide complexes demonstrate red and green luminescence owing to the distinctive transitions of Sm
3+
and Tb
3+
ions, respectively. Energy transfer
via
antenna effect clearly reveals the effective transfer of energy from the chromophoric moiety to the Ln
3+
ion. The prepared conducting and luminescent Ln(
iii
) complexes might be employed as the emitting component in designing OLEDs.
A series of lanthanide complexes have been synthesized with fluorinated 1,3-diketones and heteroaromatic ancillary moieties.
Solid ternary europium complexes consisting of fluorinated β‐diketone (thenoyltrifluoroacetone, TTFA) and heteroaromatic bidentate auxiliary ligands were synthesized. The luminescence features of the ...complexes were estimated using various spectral measurements and clearly proved that the Eu3+ ion is efficiently sensitized by ligands by an antenna effect. Photoluminescence excitation spectra have shown that Eu(III) complexes are excited effectively in the ultraviolet (UV) region and the corresponding emission spectra consist of characteristic peaks attributed to the 5D0→7FJ transitions of the europium ion with the strongest emission peak at 611 nm (5D0→7F2). From photoluminescence (PL) data, decay time, Judd–Ofelt parameters, transition rates, and quantum efficiency of the complexes were also determined. The Commission Internationale de l'éclairage (CIE) colour coordinates indicated the bright red emission of ternary europium complexes. Correlated colour temperature values indicated the utilization of these complexes in display devices. Judd–Ofelt and photophysical parameters were also estimated theoretically using LUMPAC software. Various frontier molecular orbitals and their respective energy were determined. These red emissive europium complexes could be utilized for fabricating solid‐state lighting systems.
A series of fluorinated Eu(III) β‐diketonate complexes with bidentate nitrogen donor auxiliary ligands were synthesized.
PL emission spectra exhibit characteristic peaks of Eu3+ ion revealing effective transfer of energy from ligand to metal ion via antenna effect.
Red luminescent materials could be utilized in fabricating solid state display devices.
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•Comprehensive analysis was done to examine the photoluminescent and optical properties of tris(2-benzoylacetophenonate)europium complexes with substituted 1,10-phenanthroline ...derivatives.•Spectroscopic analysis suggested the octacoordinated environment around Eu3+ ion.•Spherical atomic coordinates indicate that the Eu3+ ion is facilitated with six oxygen and two nitrogen atoms of BAP and auxiliary units respectively.•Geometry optimization was done and energies of various frontier molecular orbitals have been estimated.•Emission peak at ∼ 612 nm hold great potential as red emitting materials for designing display devices.
We have synthesized a series of heteroleptic luminescent europium moieties based on 1,10-phenanthroline and its derivatives (L) namely Eu(BAP)3L; BAP = 2-benzoylacetophenone. The structural inspection of complexes was done by several spectroscopic techniques. Energy band gap values of complexes lie in region of semiconductors. Metal-ligand interaction results a notable effect on the η (quantum efficiency) and Ω2 (JO parameters) of the prepared complexes. A detailed explanation about photophysical characteristics of the complexes was studied via theoretical and experimental methods. With the help of LUMPAC, theoretical photophysical properties were calculated and discovered to be in good concurrence with experimental values. The hypersensitive electric dipole peak positioned at 612 nm (5D0→7F2) is reasonable for the red emission. The color coordinates are also situated in the red region of CIE triangle. Therefore, these efficient materials could be utilized as red emanating material in designing various display devices.
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Fossil fuel has empowered a remarkable era of prosperity and development of the welfare of human society. However, the resulting large anthropogenic CO2 emissions had an adverse ...impact on global temperature. Furthermore, the scarcity of limited fossil fuel resources will eventually force them to look for alternative carbon sources to sustain a sustainable economy. Chemical fixation of CO2 into fuels and valuable chemicals via renewable energy sources has been attracting human society for not only alleviating CO2 emissions but also reducing reliance on non-renewable energy sources and minimizing the impact on the environment from displaced fossil fuel fractions. Cyclic carbonate is a valuable CO2 product that can be used as aprotic solvent, the electrolytic solvent in lithium batteries, degreasing solvents, and intermediates for the synthesis of polycarbonates, drugs, and cosmetics. It can be synthesized via cycloaddition of CO2 with epoxide under the catalytic condition due to the low reactivity of CO2 (thermodynamic as well as kinetic inert). An ideal catalyst for this conversion is composed of a Lewis acid to activate the epoxide ring and a Lewis base to open the epoxide ring. Efforts have been done to synthesize various catalytic systems for cyclic carbonate formation. The review is focused on metal-catalyzed cyclic carbonate formation. It begins with carbon capturing, storage, and utilization (CCSU) along with the importance of cyclic carbonate. The mechanism for cyclic carbonate formation was classified into two categories including binary and bifunctional systems based on the presence of nucleophilic moiety either as a separate entity or attached to a catalyst. Various metal catalysts such as metal salen, metal porphyrin, metal salts, metal–organic framework, and zeolitic imidazolate framework are discussed with recent progress in the development. It was believed that homogeneous catalysts showed high catalytic activity but difficult product separation whereas heterogeneous catalysts can be easily separated by simple filtration. Finally, the conclusion and the future outlook in the development of catalysts for cyclic carbonate formation are mentioned.
A series of lanthanide (samarium and terbium) β‐diketonates with heteroaromatic auxiliary ligands was synthesized. The prepared complexes were characterized through electrochemical, thermal, and ...spectroscopic analyses. Infrared analysis revealed the binding of the respective metal ion to oxygen and nitrogen atoms of diketone and ancillary ligands. Thermogravimetry/differential thermogravimetry profiles provided thermal information and specified the high thermal stability of the prepared complexes. The complexes exhibited the sharp and structured Ln‐based emission in the visible region upon irradiation in the ultraviolet range. Photophysical analysis demonstrated the green and orange‐red emission due to the respective characteristic transitions of Tb3+ and Sm3+ ions. Photophysical properties affirmed the luminous behaviour of the synthesized complexes. These luminous lanthanide complexes could be used as emitting materials in the design of organic light‐emitting diodes.
Octa‐coordinated Ln(III) {Sm, Tb} complexes with 2,2‐dimethyl‐6,6,7,7,8,8,8‐heptafluoro‐3,5‐octanedione (Hfodo) and 1,10‐phenanthroline (Phen) derivatives were synthesized. The bathochromic shift of absorption maxima is observed after complexation in respective series. Synthesized complexes show the sharp and structured Ln‐based emissions in visible region upon irradiation in UV range. The luminous nature of prepared complexes specifies the effective intramolecular energy transfer to Ln3+ ion via sensitization mechanism.
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•Structural and photophysical investigation of luminescent red color emissive ternary europium complexes have been carried out experimentally and theoretically.•The foremost purpose ...of investigation is to study the impact of substituted neutral ligands on optoelectronic properties of complexes.•Photoluminescence emission spectra specify that fluorinated β-diketone ligand have efficiently sensitized Eu(III) ion via antenna effect.•Red color emanating synthesized materials could found good significance in solid state electronics and OLEDs.
The photophysical and optoelectronic characteristics of a series of ternary europium complexes having general formula Eu(TFNB)3L were estimated in detail. The synthesized octa coordinated complexes have different heteroaromatic ancillary ligand (L) i.e., 1,10-phenanthroline (Phen) derivatives. The synthesized heteroleptic europium complexes were thoroughly characterized by various techniques. Photoluminescence emission spectra specify that β-diketone ligand has efficiently sensitized Eu (III) ion through antenna effect which results in excellent luminescent intensity and long decay time. Most intense peak accredited to 5D0→7F2 is accountable for red luminescence of complexes. By investigating the PL emission data, CIE color coordinates were calculated which indicates that subsequent complexes give emission in red region. The Judd-Ofelt parameters of trivalent europium complexes were calculated and also derived theoretically via computational methods. The higher value of hypersensitive electric dipole Ω2 intensity parameter displays the existence of highly polarizable chemical environment around central metal ion. Red light emanating materials might have found good significance in solid state electronics, flat panel devices and OLEDs.
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•Octacoordinated luminous Dy(III) complexes were synthesized with DPD and 1,10-phenanthroline derivatives.•IR and 1H NMR studies suggest the bonding between organic moieties and Dy3+ ...ion.•Hypersensitive peak around 575 nm corresponding to 4F9/2 → 6H13/2 transition is responsible for yellow emission.•Dysprosium’s conducting and thermally stable complexes demonstrate their use in fabricating OLEDs.
Several luminescent ternary dysprosium complexes were synthesized and examined using diketone ligand 1,3-diphenylprop-1,3-dione (DPD) and various auxiliary ligands. Spectroscopic analysis was carried out to determine the structural and photophysical features of Dy (III) complexes. IR and proton NMR spectroscopic studies suggested the bonding of chelating moieties to the metal ion through oxygen and nitrogen atom. The optical and electronic band gap is evaluated which proposed the conducting behaviour of dysprosium complexes. Upon excitation with UV radiation, three distinct emission peaks of the Dy (III) ion are appeared at about 485 nm (J = 15/2), 575 nm (13/2) and 664 nm (11/2) corresponding to the transitions of type 4F9/2 → 6HJ. The strongest emission peak obtained at ∼ 575 nm is responsible for yellow emission of Dy (III) complexes. The yellow to blue (Y/B) ratio estimated for the transition J = 13/2 / J = 15/2 were found to be in the range of 4.19 – 2.80. The quantum yield was also determined for the Dy (III) complexes which is as: Φ1 = 0.315, Φ2 = 0.261, Φ3 = 0.183, Φ4 = 0.157. The synthesized dysprosium complexes demonstrate luminescence lifetime in decreasing order i.e. 0.600 ms > 0.510 ms > 0.431 ms > 0.323 ms. Furthermore, the chromaticity coordinates also confirm their yellow luminous behavior. These newly synthesized complexes could be utilized for developing systems significant for lighting, OLEDs and displays due to their luminous features.
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•Red emissive complexes with Eu(TFFB)3L stoichiometry were synthesized and investigated by spectroscopic studies.•Red emissive behavior of the complexes was characterized by ...photoluminescence study.•Photophysical characteristics of the mononuclear Eu(III) complexes were analyzed theoretically (JOES) and experimentally.•Probability amplitude distribution and the energy of HOMO and LUMO were estimated through DFT.
Heteroleptic trivalent complexes of europium were prepared on reaction of EuCl3·6H2O, fluorinated 1,3-diketone and 2,2′-bipyridine or its derivatives in the molar ratio of 1:3:1 respectively. Structural analysis of prepared complexes was done via spectral study. Luminescence features of synthesized complexes have been explored by the photoluminescence and decay spectral profile. Strong emission in the red spectral region was observed for Eu3+ ion corresponding to the electric dipole 5D0 → 7F2 hypersensitive transition. The radiative transition probabilities as well as the Judd-Ofelt parameters were computed and discussed. Complexes emit red light in the visible spectrum as illustrated by their CIE color coordinates are essential for creating effective display and lighting devices.
