•A series of four trifluorinated complexes of Eu(III) were synthesized and characterized spectroscopically.•The emission spectra of complexes exhibit hyperintense peak at about 612 nm which is ...significant for their red emission.•Judd Ofelt parameters provide information about structural and chemical environment around central trivalent ion.•The band gap values show their semiconducting characteristics are responsible for their applications in photonic devices.
This article presents the preparation and characterization of a series of four tris-β-diketonate Eu(III) complexes with formulation of Eu(tfaa)3(L)n, tfaa denotes the 1,1,1-trifluoroacetylacetone, L to monodentate or bidentate neutral ligand with nitrogen and oxygen as donor atom and n can be 1 and 2. The characterization of synthesized complexes was done using infrared spectroscopy, thermo-gravimetric analysis and proton NMR spectroscopy. UV–vis absorption, photoluminescence as well as time-resolved luminescence spectroscopies were also employed to examine the spectroscopic features of ternary complexes. The proton NMR and IR spectral information has suggested the bonding of organic moieties to the Eu(III) ion. The chemical shift obtained for the protons of primary and secondary moieties are shifted in an opposite direction. The band gap values (optical and electronic) suggest the semiconducting nature of prepared europium complexes. The trivalent ion centered emission is shown by all the prepared complexes on excitation under UV-light. The hypersensitive peak situated at about 612 nm responsible for red emission is corresponding to 5D0→7F2 transition and found to be sensitive to the chelating environment present at around emissive ion. Red emanating europium materials have acquired significant utilization in OLEDs, flat panel displays and solid state electronics.
Display omitted
Display omitted
•Monometallic heteroleptic complexes of Dy(III) with general formula Dy(Hfodo)3L have been synthesized.•The prepared complexes have been investigated by thermal, spectroscopical and ...electrochemical studies.•Electronic and optical band gap has found to be quite similar and in the range of conducting region.•Yellow luminescence is observed corresponding to 4F9/2→6H13/2 transition which demonstrates the utility of complexes in generation of high-efficiency organic light emitting materials.
A series of ternary complexes of dysprosium tris-β-diketonate was prepared by using phenanthroline and its substituted derivatives as neutral ligands. The complex formation or the coordination mode of organic moieties was analysed by elemental, infrared, proton NMR and UV–Visible analyses. The anhydrous nature of prepared complexes was illustrated by using thermogravimetric and infrared studies. The band gap was also measured which is present in the range of conducting zone. The luminescence characteristics were measured in solid and solution. The complex upon excitation under UV light generates emission in the yellow region which indicates proficient energy transference from coordinated moieties to the central Dy(III) ion. The correlated color temperature (CCT) of Dy(III) complexes has been calculated and found to be ∼ 5000 K which belongs to a cold light region. The contribution of 4F9/2 → 6H13/2 transition (75 %) is highest towards total radiative processes and it might be regarded as an acceptable transition for laser amplification. The prepared complexes of Dy(III) could be utilized in fabricating OLEDs and displays due to their band gap value, large thermal stability and high luminous characteristics.
Dysprosium (Dy3+) containing four single-molecule complexes with 1,3-diketone ligand, TFPB (4,4,4-trifluoro-1-phenyl-1,3-butadionate) along with neutral co-ligands of varying denticity were ...synthesized and two of them were explored as potential sources of near-white light emission. The choice of ligand as well as the coordination surroundings of Dy(III) ion significantly influence the blue (B: 4F9/2 → 6H15/2) and yellow (Y: 4F9/2 → 6H13/2) emissions. The inclusion of the auxiliary ligand such as topo in D1 leads to reduction in emission intensity compared to D2-D4 due to less effective sensitization. At room temperature, the CIE color coordinates for complexes D1 and D4 approach the coordinates of perfectly balanced and idealized white light (0.333, 0.333). Furthermore, Correlated Color Temperature (CCT) values for D1 and D4 characterize them as cold-white-light emitters, while the complexes D2 and D3 are categorized as a neutral-light emitter. In addition to their visible emissions, the semi-conducting properties and suitable deactivation lifetime corresponding to these synthesized complexes (D1-D4) have also been extensively studied and found potential applications in basic research, security printing, sensors, detectors and OLEDs.
Display omitted
•Synthesized luminescent dysprosium complexes incorporating 1,3-diketone and neutral ligands.•Investigated PL emission spectra for understanding their near-white and yellow emission.•Quantified the complex's color in terms of CIE 1931 color space with measurement of the intensity of color.•Compared photoluminescent properties of complexes on the basis of denticity of coordinating moieties.
The set of four ternary coordination compounds of terbium were prepared with diketone 1,1,1-trifluoro-5,5-dimethyl-2,4-hexanedione (TFDH) and four different neutral ligands (L) having formula ...Tb(TFDH)3L. Resulting compounds were characterized using different techniques including NUV absorption studies, photoluminescence (PL) spectroscopy, electrochemical and thermal analyses. PL spectra confirmed the green luminescence of synthesized complexes by exhibiting characteristic dominant 5D4 → 7F5 peak around 545 nm. Electronic and optical energy gap values lying at ∼3.5 eV reveals their potential to use in semiconductor materials. All the spectral results are in good agreement with each other and highlight their utility in lighting, biomedical imaging and sensors etc.
Display omitted
•Ternary Tb(III) complexes were prepared using β-diketone and 1,10-phenanthroline based neutral ligands.•NMR spectra exhibited dipolar shift due to the paramagnetic nature of terbium ion.•The optical band gap and the electronic band gap lie within the semiconductor range.•5D4.→ 7F5 MD transition is responsible for the green luminescence in the synthesized complexes.
This study synthesizes and characterizes luminescent ternary samarium complexes (S1–S4), formulated as Sm(L)
3
(S)
n
, where the variable
n
ranges from 2 for monodentate ligands to 1 for bidentate ...ligands. In the formulation, L represents Trifluoroacetylacetone (tfaa) and S signifies various Lewis bases i.e. Tri-n-octylphosphine oxide (TOPO, S1), 1,10-phenanthroline (phen, S2), Neocuproine (NeoC, S3) and Bathocuproine (BathoC, S4). The prepared Sm(III) complexes were characterized through various analytical as well as spectral techniques. The peaks observed at around 415 and 520 cm
−1
in FTIR spectra imply the formation of coordination bond between Sm(III) ion and –O and –N atoms of tfaa and neural moieties, respectively. In NMR spectra of complexes, diketone and neutral ligand protons exhibit notable downfield and upfield shifts, reflecting the paramagnetic influence of samarium ion. The complexes exhibit thermal stability upto 240 °C, thereby demonstrating their suitability for utilization in display devices. Photophysical characteristics were assessed through photoluminescence (PL) and excited state lifetime measurements. The complexes exhibited a hyperintense peak at around 648 nm (
4
G
5/2
→
6
H
9/2
) which is sensitive to ligand environment and associated with the characteristic orange-red emission. The comprehensive investigation supports the potential of these complexes in photonic and display devices.
•Coordination sphere effects: Spectroscopic analysis of samarium β-diketonate complexes.•Emission peak at 648 nm: Electric dipole transition responsible for characteristic orange-red ...emission.•Spectroscopic evidence confirms octacoordinated samarium ion with carbonyl oxygen and nitrogen coordination.•Semiconducting properties and good thermal stability suggested display applications.
Ternary Sm(III) complexes of general representation Sm(TFDH)3L were synthesized to understand influence of different auxiliary moieties on their optoelectronic properties. The synthesized complexes were thoroughly investigated using elemental, IR, NMR, UV and PL studies. In these complexes, the emitting metal ion is bonded with six O atoms from di-ketone 1,1,1-trifluoro-5,5-dimethyl-2,4-hexanedione and two nitrogen atoms from neutral ligand i.e. 1,10-phenanthroline and its derivatives. Proton NMR spectral data showed that samarium ion induced chemical shift is dipolar in nature. The photoluminescence analysis showed that the complexes show intense orange-red emission due to 4G5/2 → 6H9/2 transition. Moreover, CIE color coordinates supported the results obtained from photoluminescence study, providing additional confirmation of the luminescent properties of prepared complexes within the orange-red region. Their utility in displays and OLED's was confirmed by studying their optical and electronic band gaps.
Display omitted
Mononuclear octacoordinated ternary Tb(III) complexes involving 1,1,1-trifluoroacteylacetone (tfaa) as main ligand and monodentate or bidentate moieties as secondary ligand, were prepared. ...Tri-n-octyl phosphine oxide (TOPO) serves as a monodentate ligand with a single donor site (–O), while 1,10-phenanthroline and its derivatives function as bidentate ligands with –N as the donor atoms. The molecular stoichiometry and bonding environment about Tb(III) ion in synthesized samples were confirmed with the help of elemental analysis and the spectroscopic studies of FTIR and proton NMR, respectively. The octacoordinated arrangement around trivalent lanthanides was the outcome of their interactions occurs with oxygen donor sites in T1 and nitrogen sites in T2-T4. The optical investigation was concentrated on examining the absorption, excitation, emission and lifetime spectral data of the complexes. The dominating peak in Tb(III) complexes observed at around 545 nm is accountable for their green color. Thermogravimetric analysis demonstrates the stability of the complexes up to 150–250 °C. The synthesized complexes exhibit significant opto-electronic characteristics and large thermal stability, making them potentially suitable for lighting applications.
Display omitted
•Successfully synthesized Tb(III) ternary complexes employing tfaa as the primary donor and monodentate & bidentate ligands as secondary donors.•Examined the bonding mode of organic ligands with Tb(III) ion through FTIR and proton NMR spectroscopies.•Investigated the optical and redox characteristics of prepared samples.•Maximum luminescence and prolonged radiative deactivation lifetime of Tb(III) with neocuproine, suggesting the effective transfer of energy from sensitizers to emissive centre.
In this study, β-diketone (1,1,1-trifluoroacetylacetone, tfaa) based mononuclear anhydrous octacoordinated dysprosium complexes i.e. Dy(tfaa)3(TOPO)2 (D1), Dy(tfaa)3(phen) (D2), Dy(tfaa)3(NeoC) (D3) ...and Dy(tfaa)3(BathoC) (D4) were synthesized using four different neutral ligands. The effect of different sensitizers on Dy(III) ion is analyzed using various spectroscopic and analytical techniques. The composition and bonding were examined by elemental analysis, infrared spectroscopy, NMR spectroscopy and thermal analysis (TGA). The luminescent characteristics of the synthesized complexes were further investigated. The complexes, when exposed to UV light, displayed characteristic emissions of the central Dy(III) ion. The photoluminescence spectra indicated the strongest emission intensity of D3 complex. The hyper-intense transition in all complexes is sensitive to the metal ion environment. The semiconducting nature of complexes was confirmed by optical and electronic band gap values obtained from absorption spectroscopy and cyclic voltammetric analysis, respectively. The neutral ligands (TOPO, phen and its derivatives) along with tfaa, are found to be good sensitizers for trivalent dysprosium ion. All the characteristic features of these prepared complexes show their potential applications in the fabrication of OLEDs.
Display omitted
•Ternary Dy-tfaa complexes were synthesized by employing monodentate & bidentate as ancillary ligand.•The mechanism of energy transfer demonstrates the efficient sensitization of Dy(III) ion occurs via photosensitizing ligands.•The hypersensitive electric dipole peak noticeable at around 575 nm due to 4F9/2 → 6H13/2 transition is responsible for the yellow emission.•Cyclic voltammetric and Tauc's analyses were conducted to study the redox behavior, electronic band gap and optical band gap, respectively.
•Synthesized dysprosium (III) complexes by utilizing TFDH with 2,2ʹ-bipyridyl and its derivatives.•FTIR and NMR confirmed coordination via oxygen and nitrogen donor atoms in ternary ...complexes.•Semiconducting behavior of complexes confirmed by optical and CV band gap values.•High luminescence lifetimes suggested applications in display devices.
The ternary dysprosium complexes involving 1,1,1-trifluoro 5,5-dimethyl 2,4-hexanedione (TFDH) along with 2,2ʹ-bipyridyl and its derivatives have been synthesized. Elemental, infrared and proton NMR analyses were used to evaluate the bonding patterns between dysprosium ion and organic moieties. UV–Visible and photoluminescence spectroscopy were used to examine the optical characteristics. To confirm the anhydrous nature of synthesized complexes, IR and thermogravimetric data were utilized. The band gap value lies in semi-conducting region was explained by Tauc's plot and CV curve, respectively. The photophysical characteristics of dysprosium complexes have been studied in powdered form. The appearance of yellow luminescence on irradiation under NUV-light indicates a highly efficient transfer of energy mechanism from organic ligand to the Dy(III) ion. The CCT values were found to be suitable for cold light sources. The ∆J = 2 transition dominates the overall emission spectra with branching ratio ∼70% is ideal for laser reinforcement. The synthesized Dy(III) complexes possess band gap in semi-conducting range, good thermal stability and high luminous properties, which makes them suitable for applications in displays and lighting technologies.
Display omitted
Abstract Four eight‐coordinated luminescent samarium complexes of type Sm(hfpd) 3 L 2 and Sm(hfpd) 3 L′ where hfpd = 1,1,1,5,5,5‐Hexafluoro‐2,4‐pentanedione L = tri‐octyl‐phosphine oxide (TOPO) and ...L′ = 1,10‐phenanthroline (phen), neocuproine (neoc) and bathocuproine (bathoc) were synthesized via a stoichiometrically controlled approach. This allows for precise control over the stoichiometry of the complexes, leading to reproducible properties. This investigation focuses on understanding the impact of secondary ligands on the luminescent properties of these complexes. Infrared (IR) spectra provided information about the molecular structures, whereas 1 H and 13 C nuclear magnetic resonance (NMR) spectra confirmed these structural details along with the coordination of ligands to trivalent Sm ion. The UV–vis spectra revealed the molar absorption coefficient and absorption bands associated with the hfpd ligand and photoluminescence (PL) spectroscopy demonstrated intense orange‐red emission (648 nm relative to 4 G 5/2 → 6 H 9/2 ) from the complexes. The Commission Internationale de l'Éclairage (CIE) triangles indicated that the complexes emitted warm orange red light with color coordinates ( x , y ) ranging from (0.62, 0.36) to (0.40, 0.27). The investigation of the band gap as well as color parameters confirms the utility of these complexes in displays and LEDs.
