Blue Materials Research Articles

Synthesis, aggregation-induced emission, and electroluminescence of AIEgen designed on bis-carbazole platform

The promising applications of organic light emitting devices (OLEDs) as the next-generation lighting technology has boosted global research on small organic fluorescent molecules. However, majority of the organic fluorophores experiences detrimental aggregation caused quenching (ACQ) during their real-world applications. Since the discovery of the AIE phenomena, efforts to develop novel luminescent materials have skyrocketed, creating newer opportunities for the improvement of the properties of the light-emissive materials for OLEDs. Herein we have reported the synthesis of bis-carbazole-derived luminogen by oxidative coupling of the carbazole in good yield. The bis-carbazole luminogen 6 displayed sky-blue-emission in the aggregated state along with excellent electrochemical property and thermal stability, which are considered essential features for constructing high efficiency OLEDs. The luminogen 6 was employed as an emitter for fabricating non-doped OLED and the device resulted in sky-blue emission with CIE coordinates (0.23, 0.41). The light emitting device had a maximum current efficiency of 3.25 cd/A and a maximum external quantum efficiency (EQE) of 5 %, which eventually rolled-off to about 2 % at a J ∼ 50 mA/cm2. Our findings presented a novel way for constructing blue emissive materials for potential application in OLED devices.

Hydrogen bond boosts EQEs to 30+% for acridone-carbazole based deep-blue TADF emitters in simple-structure OLEDs

A group of D-A-D type thermally activated delayed fluorescence (TADF) emitters were developed with 10-(pyridin-2-yl)acridin-9(10H)-one as acceptor and substituted carbazoles as donors. The design was focused on incorporating pyridyl to the 10-site nitrogen atom of acridin-9(10H)-one ring, which improved the reverse intersystem crossing rate constant kRISC from 103 s−1 to 105 s−1. More importantly, the linkage of pyridyl uniquely from its 2-position to acridin-9(10H)-one ring induced intramolecular hydrogen bond, which suppressed nonradiative transition rates by three to four orders of magnitude and universally increased the photoluminescence quantum yields from 54 % to nearly 100 %. In combination with the intrinsic high horizontal orientation ratios over 90 % of acridin-9(10H)-one based molecules, such pyridyl decoration boosted the external quantum efficiencies of simple-structure deep blue organic light-emitting diodes to 31–33 % with CIEx of 0.15 and CIEy of 0.09 ∼ 0.12, being double of that for hydrogen-bond-free parent emitter and representing the state-of-the-art efficiencies for the deep blue twisted intramolecular charge transfer type TADF materials with CIEy ≤ 0.10 so far. These TADF emitters are comparable with the prevailing multiresonance blue emitters in terms of distinctive efficiencies, but advantageous in much facile syntheses.

Highly efficient deep blue electroluminescent material with high and towards balanced carrier transmission performance based on hybrid local and charge-transfer (HLCT) excited state

Deep blue electroluminescent materials play a decisive role in organic light-emitting diodes (OLEDs). Herein, three novel deep blue molecules based on hybridized local and charge-transfer (HLCT) excited state were reported, namely CZFPY, CZFPI and TPAFPI. Single-crystal analysis of TPAFPI shows abundant intermolecular interactions, which restricts molecular rotation and suppresses structural vibrations, promotes TPAFPI achieved a high photoluminescence quantum yield (PLQY) up to 72 % in solid state. More importantly, these abundant intermolecular interactions significantly increase its carrier mobilities, with hole and electron mobilities as high as 1.2 × 10−5 cm2 V−1 s−1 and 5.4 × 10−6 cm2 V−1 s−1, respectively. Consequently, the non-doped OLED based on TPAFPI achieved excellent device performance, the maximum current efficiency (CEmax) is 12.4 cd/A, the maximum power efficiency (PEmax) is 14.0 lm W−1, the maximum external quantum efficiency (EQEmax) is 7.2 % with high device stability, the efficiency roll-off is only 4.7 % at 1000 cd m−2. What is more, the doped device of TPAFPI exhibits a higher EQEmax of 10.1 % with a higher color purity, the Commission International de L’Eclairage (CIE) coordinate is (0.15, 0.06), matching the National Television Standards Committee (NTSC) standard. The comprehensive performance of TPAFPI-based doped device is at the highest level in the field of deep blue OLEDs (0.06 ≤ CIEy ≤ 0.09).

Nitric Acid-Treated Blue Coke-Based Activated Carbon's Structural Characteristics and Its Application in Hexavalent Chromium-Containing Wastewater Treatment.

This study primarily focused on the efficient transformation of low-priced blue coke powder into a high-capacity adsorbent and aimed to address the pollution issue of hexavalent chromium (Cr (VI))-laden wastewater and to facilitate the effective utilization of blue coke powder. A two-step method was utilized to fabricate a blue coke-based nitric acid-modified material (LCN), and the impact of nitric acid modification on the material's structure and its efficacy in treating Cr (VI)-contaminated wastewater was evaluated. Our experimental results illustrated that, under identical conditions, LCN exhibited superior performance for Cr (VI) treatment compared to the method employing only potassium hydroxide (LCK). The specific surface area and pore volume of LCN were 1.39 and 1.36 times greater than those of LCK, respectively. Further chemical composition analysis revealed that the functional group structure on the LCN surface was more conducive to Cr (VI) adsorption. The highest amount of Cr (VI) that LCN could bind was measured at 181.962 mg/g at 318 K. This was mostly due to chemisorption, which is dominated by redox reactions. The Cr (VI) removal process by LCN was identified to be a spontaneous, exothermic, and entropy-increasing process. Several tests on recycling and reuse showed that LCN is a stable and effective chromium-containing wastewater adsorbent, showing that it could be used in many situations.

Recent progress of manganese-based Prussian blue analogue cathode materials for sodium-ion batteries

Recent progress of manganese-based Prussian blue analogue cathode materials for sodium-ion batteries

Versatile deep blue fluorescent materials based on the hybridization of phenanthroimidazole and fluorene derivatives

Blue fluorescent materials are an essential part of commercial OLED displays and lightings. However, the market lacks highly efficient, short-emission wavelength blue fluorescent materials. Herein, two new blue fluorescent materials, SAFPI-3 and SAFPI-2, are developed based on a phenanthroimidazole derivative and spiro fluorene triphenylamine by replacing the substitution sites, which tactfully utilize the spatial configuration of the molecules to achieve higher external quantum efficiency and a shorter emission wavelength at the same time. Furthermore, the versatility of SAFPI-3 and SAFPI-2 can be demonstrated as non-doped emitters for blue OLEDs and as the hosts of yellow phosphorescent OLEDs, which have achieved a high external quantum efficiency of 23.98% with extremely low-efficiency roll-off.

Blue polyimides for high-performance solution-processable organic light-emitting diodes

Blue light-emitting materials with excellent film-forming ability, superior morphological stability, outstanding color purity, and high device efficiency are in urgent demand for new-generation display and solid-state lighting devices fabricated by low-cost wet processing. However, their current performances are far from satisfactory. Herein, two polyimide (PI)-based blue polymers are first precisely constructed and synthesized through a “Hinge-type Linking” strategy. A small molecular is introduced into the PI backbone via non-conjugated aliphatic imide ring linker. These polymers not only show superb thermal stability and morphological stability, but also maintain narrowband blue emission. Furthermore, PIs are prepared by polycondensation method, precipitated and purified in ethanol solvent, which avoids the use of metal catalysts. The resulting solution-processable devices achieve high performance with a maximum external quantum efficiency (EQE) of 9.94 % and maximum emission peak at 460 nm. To the best of our knowledge, this is the first time that solution-processable polymer light-emitting diodes (PLEDs) based on the “hot exciton” mechanism achieving splendid performance with maximum EQE close to 10 %. The superior performance is attributed to the validity of the “Hinge-type Linking” strategy in PLEDs, opening up a new avenue for PLED development and application.

Synthesis and Fluorescent Characteristics Study of Two Novel Co(II) Complexes.

In this work, two novel mixed-ligand CPs that has a compositions of [Co2(µ-Hdppa)2(phen)2(H2O)2] (1) and {[Co(µ-Hdppa)(µ-4,4'-bipy)(H2O)]·H2O}n (2) is achieved through reaction of cobalt salts with the 5-(3,4-Dicarboxylphenyl)picolinic acid (H3dppa) with various N-donor co-ligands (1,10-phenanthroline (phen) for 1 and 4,4'-bipyridine (4,4'-bipy) for 2). The structures and characteristics of these two complexes were fully examined via IR, TGA, and SXRD. Furthermore, their superior blue fluorescence properties compared to the original ligands were confirmed through fluorescence spectroscopy. These two complexes prepared in this study have enriched the choices for blue fluorescent materials.

Crystallization and optical properties of Eu2+: CsCaCl3 nanocrystals in glasses

Narrow-band blue luminescence materials are desirable in full color display with wide color gamut. Divalent rare earth europium doped luminescence materials show excellent optical properties as promising backlit materials in display. However, narrow-band blue luminescence materials are still lacking. Herein, novel blue emitting Eu2+: CsCaCl3 NCs are precipitated in the glasses, and effects of EuCl3 doping concentration and heat-treatment conditions on the growth behavior and optical properties of Eu2+: CsCaCl3 NCs precipitated in glasses are investigated. Doping concentration of EuCl3 in glass and the heat-treatment condition can effectively regulate the Eu2+/Eu3+ molar ratio in glasses, size of Eu2+: CsCaCl3 NCs, and effective doping concentration of Eu2+ ions in CsCaCl3 NCs formed in the glasses. Besides, effect of phase separation on glass transmittance is explored to improve the glass optical properties. Upon incorporation of Eu2+ ions into CsCaCl3 NCs in glasses, blue photoluminescence at 435 nm with full width at half maximum of 22 nm and color purity of ∼97.2 % is realized, and concomitantly, photoluminescence lifetimes are extended and quantum efficiency are significantly improved. These results demonstrate that Eu2+: CsCaCl3 NCs doped glasses are promising blue emitting materials.

Blue phosphorus-like layered GeTe for high rate and long cycle Li-ion batteries

The blue phosphorus with unique layered structure and high reactivity shows great potential for advanced energy storage and conversion, while it can't be synthesized and stabilized at normal pressure & temperature on thermodynamics thus fail in battery application. Herein, a stand-in of blue P, e.g., blue phosphorus-like layered GeTe, is interestingly found to possess similar rhombohedral structural characteristics and properties like blue P. Furthermore, other germanium-based sulfides, e.g., GeS and GeSe, which account for the orthorhombic layered structure like black phosphorus, are also synthesized and investigated the lithiated-behavior for comparison. Different from the “armchair” edge feature of black phosphorus-like GeS & GeSe, this blue phosphorus-like GeTe exhibits a unique “zigzag” arrangement toward smaller band gap (0.56 eV) and thus higher conductivity (4.3 × 101 S m−1). Benefitted from above structural advantages, this blue phosphorus-like atomic arrangement of GeTe enables an obvious lithiated-conversion plateau, higher Li-diffusivity (6.02 × 10−11 cm2 s−1), larger faradaic pseudo-capacitive contribution (79.2 %) and thereby, better rate capability (851 mAh g−1 and 78 % retention at 2000 mA g−1) and cyclability (948 mAh g−1 and 93 % retention after 300 cycles) can be obtained. The above investigation of GeTe for Li-ion batteries may give a better understanding of electrochemical behaviors of blue phosphorus-like layered materials toward advanced energy storage.

Preparation of Low-Defect Manganese-Based Prussian Blue Cathode Materials with Cubic Structure for Sodium-Ion Batteries via Coprecipitation Method.

Sodium-ion batteries have important application prospects in large-scale energy storage due to their advantages, such as safety, affordability, and abundant resources. Prussian blue analogs (PBAs) have a stable and open framework structure, making them a very promising cathode material. However, high-performance manganese-based Prussian blue cathode materials for sodium-ion batteries still suffer from significant challenges due to several key issues, such as a high number of vacancy defects and a high crystal water content. This article investigates the effects of the Fe-Mn molar ratio, Mn ion concentration, and reaction time on the electrochemical performance of MnHCF during the coprecipitation process. When Fe:Mn = 1:2, c(Mn2+) = 0.02 mol/L, and the reaction time is 12 h, the content of interstitial water molecules in the sample is low, and the Fe(CN)6 defects are few. At 0.1 C, the prepared electrode has a high initial discharge specific capacity (121.9 mAh g-1), and after 100 cycles at 0.2 C, the capacity retention rate is 65% (~76.2 mAh g-1). Meanwhile, the sample electrode exhibits excellent reversibility. The discharge capacity can still be maintained at around 75% when the magnification is restored from 5 C to 0.1 C. The improvement in performance is mainly attributed to two aspects: On the one hand, reducing the Fe(CN)6 defects and crystal water content is conducive to the diffusion and stable structure of N. On the other hand, reducing the reaction rate can significantly delay the crystallization of materials and optimize the nucleation process.

Three-Dimensionally Printed, Vertical Full-Color Display Pixels for Multiplexed Anticounterfeiting.

Information encryption strategies have become increasingly essential. Most of the fluorescent security patterns have been made with a lateral configuration of red, green, and blue subpixels, limiting the pixel density and security level. Here we report vertically stacked, luminescent heterojunction micropixels that construct high-resolution, multiplexed anticounterfeiting labels. This is enabled by meniscus-guided three-dimensional (3D) microprinting of red, green, and blue (RGB) dye-doped materials. High-precision vertical stacking of subpixel segments achieves full-color pixels without sacrificing lateral resolution, achieving a small pixel size of ∼μm and a high density of over 13,000 pixels per inch. Furthermore, a full-scale color synthesis for individual pixels is developed by modulating the lengths of the RGB subpixels. Taking advantage of these unique 3D structural designs, trichannel multiplexed anticounterfeiting Quick Response codes are successfully demonstrated. We expect that this work will advance data encryption technology while also providing a versatile manufacturing platform for diverse 3D display devices.

Clarifying the complex chemistry of cobalt(II) thiocyanate-based tests for cocaine using single-crystal X-ray diffraction and spectroscopic techniques.

Cobalt(II) thiocyanate-based tests are routinely used to screen cocaine products, with the formation of a blue species interpreted as a positive response. An array of other organic bases has been identified as false positives - including well-documented cocaine product adulterant lidocaine and its salt. False positives prompt continued test development, though improvements are hindered by unresolved product structures and reaction pathways. Toward greater clarity, cobalt(II) thiocyanate reactions with cocaine hydrochloride, along with lidocaine and its salt, were investigated using multiple analytical techniques. Reactions involving cocaine hydrochloride yielded glassy, amorphous blue material while reactions of lidocaine hydrochloride monohydrate produced larger, needle-like crystals whose structure was determined via single-crystal X-ray diffraction to be an ion pair (Hlidocaine+ )2 ([Co(SCN)4 ]2- )·H2 O. While the blue precipitate isolated from reactions involving cocaine hydrochloride was unsuitable for crystallographic structure determination, comparative ultraviolet-visible, attenuated total reflectance infrared, and Raman spectroscopic analysis - along with elemental analysis - supports that this solid is comprised of a comparable ion pair (Hcocaine+ )2 [Co(SCN)4 ]2- . Pink crystals isolated from lidocaine reaction vessels were identified as coordination compounds cis-[CoL2 (SCN)2 ] and trans-[CoL2 (SCN)2 ] where L = lidocaine, while pink crystals from both cocaine hydrochloride and lidocaine hydrochloride monohydrate reaction vessels were the coordination polymer trans-[Co(H2 O)2 (SCN)2 ]·H2 O. The results presented herein enable reaction optimization to favor a desired product, whether ion pair or coordination species.

Thiophene derived sky-blue fluorescent probe for the selective recognition of mercuric ion through CHEQ mechanism and application in real time samples

A vibrant blue organic luminescent material with enhanced photophysical properties is in great demand for the generation of optoelectronic devices and luminescent sensors. In this context, the thiophene-benzimidazole probe TH-IMI was designed and synthesized by a simple condensation reaction. The synthesized probe has shown excellent photophysical properties like high FL intensity, a high quantum yield of 90% in the solution phase, a low optical bandgap of 2.84 eV, positive solvatochromic effect in emission spectra and Disaggregation Caused Quenching Effect (DCQE). Such a high luminescent probe was employed for the recognition of mercuric ions in the solution phase, solid state detection, and in tracking mercury in green gram sprouts. UV–visible absorption and emission spectra, 1H NMR titration, IR spectroscopic and ESI-MS techniques confirmed that the probe underwent a fluorescence quenching response via the CHEQ effect upon exposure to Hg2+. The stoichiometry was found to be 1:1 through Job’s plot and has a fast response rate and relatively low limit of detection of about 6.13 × 10-11 M in a linear range between 0 and 110 µL.

Drastic Photoemission Color Alternation from a Single Molecule as a Starting Material Introduced in Acid-Treated Zeolites: From Pure Blue to White.

Since high-purity blue- and white-light emitters are an indispensable group of materials for the creation of next-generation optical devices, a number of light-emitting materials have been developed from both inorganic and organic synthetic chemistry. However, these synthetic chemical methods are far from the perspective of green chemistry due to the multistep synthetic process and the use of toxic reagents and elements. Herein, we demonstrate that the introduction of simple unsubstituted anthracenes into zeolite-like pores can create a wide variety of luminescent materials, from ultrapure blue luminescent materials (emission peak at 465 nm with a full width of half-maximum of 8.57 nm) to efficient white luminescent materials [CIE coordination at (0.31, 0.33) with a quantum efficiency of 11.0% under 350 nm excitation light]. The method for rational design of the luminescent materials consists of the following two key strategies: one is molecular orbital confinement of the anthracene molecules in the zeolite nanocavity for regulating the molecular coordination associated with photoexcitation and emission and the other is the interaction of unsubstituted anthracenes with extra-framework aluminum species to stabilize the 2-dehydride anthracene cation in the zeolite cavity.

Pioneering ginger juice extract mediated synthesis of magnesium indate nanoparticles

Magnesium indate nanoparticles were synthesized via a biomediated route using ginger extract as a reducing agent followed by calcination. The Bragg reflections confirm the formation of an orthorhombic crystal structure with space group Imma. This was in turn confirmed through Rietveld refinement. The crystallite size and other structural parameters were calculated. Agglomerated irregularly sized and irregularly shaped nanoparticles were observed. The direct band gap was found to be 3.16 eV. Photoluminescence analysis was performed with excitation at 250 nm. The photoluminescence intensity and CIE values drop in the blue region of the visible spectrum. The correlated color temperature was found to be 2748 K. Further, the powder dusting method was used to collect latent fingerprints on porous and nonporous surfaces. The synthesized magnesium indate results in well-resolved ridge patterns that can be used to identify latent fingerprints with clarity. From all these results, the present synthesized magnesium indate nanoparticles might find application in display technology as a blue nanophosphor material and for latent fingerprint detection in forensic science.

Metal Halide Single Crystals RbCdCl3:Sn2+ and Rb3SnCl7 with Blue and White Emission Obtained via a Hydrothermal Process.

Until now, effective blue light-emitting materials are essentially needed for the creation of white light and precise color renderings in real-world applications, but the efficiency of blue light-emitting materials has lagged far behind. Here, we present a hydrothermal method to synthesize tin-based metal halide single crystals (RbCdCl3:Sn2+ and Rb3SnCl7). Two single crystal materials with different shapes and phases can simultaneously be synthesized in the same stoichiometric ratio. Rb3SnCl7 has a bulk shape, while RbCdCl3:Sn2+ has a needle shape. The deep blue emission (436 nm) of RbCdCl3:Sn2+ can be obtained under the optimal excitation wavelength irradiation. However, pure blue emission (460 nm) to white light can be obtained by changing the excitation wavelength in Rb3SnCl7. The refinement spectra of the electronic structures of RbCdCl3:Sn2+ and Rb3SnCl7 are investigated by density functional theory. It is concluded that the difference in the distribution of Cl energy states leads to the existence of Cl local defect states, which is the reason for the rich luminescence of the two single crystals. These findings provide a path for realizing single-phase broadband white-emitting materials.

Lupus erythematosus cells in a bone marrow aspirate.

A teenage girl presented with fevers of unknown origin and pancytopenia. Complete blood count showed anemia (hemoglobin, 9.0 g/dL), neutropenia (1.7 × 109/L), and thrombocytopenia (66 × 109/L). The bone marrow was hypocellular with left shifted hematopoiesis and myeloid hypoplasia. Aspirate smears were notable for a prominent population of neutrophils with crescentic nuclei that engulfed blue amorphous material (Fig.1panels A and B, Wright-Giemsa, magnification × 1000). The trephine biopsy showed similar cells with crescentic nuclei and eosinophilic material (Fig. 1panels C and D, hematoxylin and eosin × 400). Flow cytometry was negative for an abnormal population. EBV by in situ hybridization and parvovirus immunohistochemistry were negative. Subsequent serologic testing was positive for ANA (1:1280), low C3/C4, anti-dsDNA, anti-SM and anti-B2GP1. A kidney biopsy demonstrated findings consistent with class III lupus nephritis.

Effect of structural evolution of attapulgite on Pickering foam and fabrication of porous materials for removal methylene blue

Effect of structural evolution of attapulgite on Pickering foam and fabrication of porous materials for removal methylene blue

A non-rare-earth-doped self-activated blue fluorescent material of transparent glass-ceramics containing single-phase NaY(MoO4)2: The controllable synthesis, crystallization behavior and luminescent properties

The glass with components of 50SiO2-20B2O3-20Na2O-6ZnO-3MoO3-1Y2O3 (mol%) was synthesized by the melt-quenching method, and the corresponding glass-ceramics were obtained after heat treatment. The crystallization behavior of the glass was characterized by the DSC test. By carefully examining the structure and grain size of the NaY(MoO4)2 crystals with scheelite structure using XRD and SEM, it can be confirmed that the crystal size steadily increases after increasing the crystallization temperature or extending the crystallization time, which is in the range of 27–45 nm. The transmittance of glass-ceramics somewhat declines compared to the precursor glass, although it remains high (>80 %). Under the excitation of 365 nm, the glass-ceramic shows a broad emission band, which is related to the charge transfer of Mo6+→O2- in the [MoO4]2- unit. The glass-ceramic is heat-treated at 590 °C for 3 h as the optimal heat treatment schedule, and its CIE chromaticity coordinate is located in the blue-light region, indicating the potential application of the non-rare-earth-doped self-activated light-emitting glass-ceramics containing single-phase NaY(MoO4)2 in the blue light-emitting field.