Solution processable truxene based blue emitters: Synthesis, characterization and electroluminescence studies

Kaur, Banpreet; Moghe, Dhanashree; Dey, Arun K.; Kabra, Dinesh; Jacob, Josemon

doi:10.1016/j.jlumin.2017.12.012

Cited by 7 publications

(8 citation statements)

References 57 publications

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“…However, the solid state emission maxima of ExT‐P was obtained at 442 nm, with a minor red shift of ∼1 nm attributable to the non‐planarity induced into the molecular system by incorporation of the pyrene groups as side moieties and additionally to the larger and rigid extended truxene moiety at the core. A similar inference can be drawn while comparing the emission maxima of truxene‐pyrene conjugate, in both solution and solid‐state, as reported in our earlier report . While moving from the solution to solid‐state spectrum of truxene‐pyrene conjugate, a large red‐shift of 42 nm and peak‐broadening was obtained, attributable to aggregation, whereas in the case of ExT‐P , this shift was very minor (∼1 nm) …”

Section: Resultssupporting

confidence: 87%

“…A similar inference can be drawn while comparing the emission maxima of truxene‐pyrene conjugate, in both solution and solid‐state, as reported in our earlier report . While moving from the solution to solid‐state spectrum of truxene‐pyrene conjugate, a large red‐shift of 42 nm and peak‐broadening was obtained, attributable to aggregation, whereas in the case of ExT‐P , this shift was very minor (∼1 nm) Furthermore, the full width‐half maximum (FWHM) value of solid‐state emission in ExT‐P was found to be 75.9 nm, a much lower value when compared to FWHM value of the previously reported truxene‐pyrene conjugate (111.9 nm) .…”

Section: Resultssupporting

confidence: 85%

“…While moving from the solution to solid‐state spectrum of truxene‐pyrene conjugate, a large red‐shift of 42 nm and peak‐broadening was obtained, attributable to aggregation, whereas in the case of ExT‐P , this shift was very minor (∼1 nm) Furthermore, the full width‐half maximum (FWHM) value of solid‐state emission in ExT‐P was found to be 75.9 nm, a much lower value when compared to FWHM value of the previously reported truxene‐pyrene conjugate (111.9 nm) . The lower FWHM value suggests better colour purity for ExT‐P in solid state emission .…”

Section: Resultsmentioning

confidence: 57%

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Design, Synthesis and Selective Functionalization of a Rigid, Truxene Derived Pure Blue‐Emitting Chromophore

et al. 2020

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A novel, rigid, solution processable, blue‐emitting chromophore based on an extended core of truxene (ExT) was designed and synthesized. The core, ExT based on a fused cyclic trimer of indenofluorene, was found to be planar in nature and a potential precursor for blue emission. This could be selectively brominated under mild conditions to generate a tribromo derivative which underwent ready Suzuki coupling to generate a trisubstituted pyrene derivative, ExT‐P. This coupling alters the kinetics of the excited state considerably as evident from transient absorption spectroscopy, showing faster singlet state decay and less triplet state formation in the case of the pyrene coupled ExT‐P (∼1.6 ns) compared to ExT (∼17 ns). The ExT‐P shows emission maxima at 441 nm and 442 nm in THF solution and film, respectively, with high PLQY value of 0.97. The negligible bathochromic shift in the solid‐state emission and narrow FWHM suggests practically no aggregation and pure blue emission in the target molecule due to bulky and rigid core.

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Section: Resultssupporting

confidence: 87%

Section: Resultssupporting

confidence: 85%

Section: Resultsmentioning

confidence: 57%

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Design, Synthesis and Selective Functionalization of a Rigid, Truxene Derived Pure Blue‐Emitting Chromophore

et al. 2020

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“…Star‐shaped molecules have appeared as interesting fluorophores in SL‐OLEDs (Figure 1, right). [ 18–20 ] As an example, pyrene‐centered starburst difluorene 9 or terfluorene 10 with solid state PL centered at 474 nm have been used as EML in SP‐SL 9 and SP‐SL 10 respectively. [ 18 ] With 9 , V on was low (3.6 V) and CE max reached 1.28 cd A −1 .…”

Section: Blue Single‐layer Oleds Using Pure Hydrocarbon Oscsmentioning

confidence: 99%

“…Truxene, a planar heptacyclic polyarene that can be considered as three annulated fluorene moieties, is the corner stone of an important class of π‐conjugated star‐shaped materials. [ 42 ] Substituted by three pyrenyl units, truxene 11 [ 19 ] presents in dilute THF solution a nonstructured PL spectrum centered at 423 nm corresponding to the emission of the pyrenyl units (Table 2). In the solid state, the PL spectrum is red‐shifted to 474 nm due to excimer emission induced by the stacking of pyrenyl units.…”

Section: Blue Single‐layer Oleds Using Pure Hydrocarbon Oscsmentioning

confidence: 99%

Blue Single‐Layer Organic Light‐Emitting Diodes Using Fluorescent Materials: A Molecular Design View Point

Poriel

Rault‐Berthelot

2020

Adv Funct Materials

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technology is mastered, it suffers from a real complexity, a high cost, and is time-consuming. Simplifying the multilayer structure with the so-called single-layer OLEDs (SL-OLEDs), the simplest device only made of the electrodes and the EML has hence rapidly appeared as a promising and appealing solution in this technology (Scheme 2, left).However, removing the functional organic layers of an OLED stack often leads to a dramatic decrease of the performance and reaching high efficiency blue SL-OLEDs has required intense researches and especially in term of materials design. Indeed, if one removes all the organic layers surrounding the EML, the efficient injection, transport, and recombination of charges within the device, should be insured by the EML itself and therefore the fluorophore. However, this appears to be a real obstacle to cross for blue emitting materials. Indeed, blue fluorophores usually possess a high HOMO and a low LUMO energy rendering the injection of charges in such materials very difficult. This has been one of the main issue to address in this field. Common properties required for high-performance blue emitting materials can be summarized as follows: 1) blue light emission between 380 and 500 nm with maximum wavelength around 450 nm; 2) a narrow full width at half maximum less than 60 nm; which produces low Commission Internationale de l'Eclairage (CIE) y-coordinate of less than 0.10 for TVs and cell phones; 3) thermal and morphological stability for stable device operation and a long device lifetime; 4) balance charge transport between electrons and holes flow and 5) adequate HOMO/LUMO energy levels for charge recombination and injection.Gathering all these properties in a single molecule is far from being an easy task and requires very precise designs. Indeed, as soon as one tries to adjust the HOMO/ LUMO energy levels of an organic semiconductor (OSC) with the Fermi levels of OLED electrodes, its gap is contracted and the emission wavelength is bathochromically shifted. This design strategy can hence lead to a material in which the charges can be more easily injected (the gap is contracted) but with an emission wavelength no more in the blue region. Trying to find the best compromise between adequate HOMO/LUMO energy and a blue emission has been the main challenge to address in the molecular design of efficient fluorophores for blue SL-OLEDs. This particularity has strongly restrained the development of such materials. However, for the last 30 years, research groups have developed many different molecular design strategies, which have led in some cases to high performance blue SL-OLEDs. Reaching high performance SL-OLEDs by molecular engineering of the fluorophore and Cyril Poriel is

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Optoelectronic and charge‐transport properties of truxene, isotruxene, and its heteroatomic (N, O, Si, and S) analogs: A DFT study

Tripathi

Chetti

2019

J of Physical Organic Chem

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The main objective of this work is to provide a detailed study of optoelectronic and charge‐transport properties of truxene, isotruxene, and their heteroatomic analogs (azatruxene and isoazatruxene, oxatruxene and isooxatruxene, silatruxene and isosilatruxene, and thiatruxene and isothiatruxene). Systematic studies of these molecules were performed by means of the density functional theory (DFT) and time‐dependent DFT (TD‐DFT) calculations. Electronic excitations (absorption spectra), reorganization energies (hole‐ and electron‐transport properties), electron affinities (EAs), ionization potentials (IPs), hole extraction potentials (HEPs), and electron extraction potentials (EEPs) for all the molecules were reported. Based on the comparative study, it is showed that thiatruxenes (isothiatruxene) are better hole‐transport materials than other truxene (isotruxene) analogs.

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Solution processable truxene based blue emitters: Synthesis, characterization and electroluminescence studies

Cited by 7 publications

References 57 publications

Design, Synthesis and Selective Functionalization of a Rigid, Truxene Derived Pure Blue‐Emitting Chromophore

Design, Synthesis and Selective Functionalization of a Rigid, Truxene Derived Pure Blue‐Emitting Chromophore

Blue Single‐Layer Organic Light‐Emitting Diodes Using Fluorescent Materials: A Molecular Design View Point

Optoelectronic and charge‐transport properties of truxene, isotruxene, and its heteroatomic (N, O, Si, and S) analogs: A DFT study

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