Blue Fluorescent Materials Research Articles

Application of Fluorescent Composite Materials as a Sustained Release System in Treatment of Polycystic Ovary Syndrome.

Polycystic ovary syndrome (PCOS) is a multifactorial disease characterized by oxidative stress and follicular dysfunction, leading to menstrual irregularities, hyperandrogenism, and infertility. Traditional drug delivery methods often result in drug loss and side effects on normal tissues. To address these issues, we synthesized two novel Co(II)-containing coordination polymers (CPs), {[Co(L)(H2O)2]·2H2O}n (1) and {[Co(L)(H2O)2]·1.5H2O}n (2), through the reaction of the T-shaped ligand (4 - 3'-pyridyl-,6 - 4'-carboxylphenyl)picolinic acid (H2L) with Co(NO3)2·6H2O via a solvothermal process. Fluorescence spectroscopy revealed that the fluorescence emission of the CPs originates from the ligand, indicating their potential application as blue fluorescence materials. Subsequently, we encapsulated these CPs with hyaluronic acid (HA) and carboxymethyl chitosan (CMCS) hydrogels to create two types of metal gel particles carrying spironolactone (HA/CMCS-CPs@spironolactone). SEM and TEM analyses showed that the material consists of tightly stacked sheet-like structures with an average size of approximately 100nm. Thermogravimetric analysis (TGA) indicated that the material begins to decompose at around 115°C, demonstrating good thermal stability. We assessed the inhibitory effects of these materials on oxidative stress induced by PCOS. The results showed that both types of spironolactone-loaded metal gel particles significantly reduced malondialdehyde (MDA) levels, particularly the particles constructed with CP2. HA/CMCS-CP1@spironolactone reduced MDA levels by approximately 17% and 46% at low and high concentrations, respectively, while HA/CMCS-CP2@spironolactone decreased MDA levels by about 55% and 39% at high and low concentrations, respectively. Therefore, the novel drug delivery system reported in this study has the potential to become a safe and effective option for the localized treatment of PCOS.

Pyrene‐Modified Blue Emitters for OLED Applications: Efficiency and Stability Advancements

AbstractBlue light materials have always posed a challenge in the OLED industry due to their high energy, which negatively impacts the stability of organic luminescent materials. Consequently, there is a significant disparity in efficiency and lifespan compared to red and green materials. In this study, we successfully synthesized three blue fluorescent luminescent materials with high fluorescence quantum efficiency by utilizing pyrene as the core. The 1,6‐positions of pyrene were substituted with diphenylamine and further modified with methoxy, isopropyl, and dibenzofuran. These modifications were introduced to enhance efficiency, increase spatial site resistance, and improve structural rigidity. Each structure exhibits a maximum current efficiency of over 8.2 cd/A and a maximum external quantum efficiency (EQE) of more than 5.8%. Notably, the compound N1,N6‐bis(4‐isopropylphenyl)‐N1,N6‐bis(2‐methoxyphenyl)pyrene‐1,6‐diamine (BD1), with methoxy modification, achieves a maximum current efficiency of 9.3 cd/A. Additionally, the compound N1,N6‐bis(dibenzo[b,d]furan‐4‐yl)‐N1,N6‐di‐o‐tolylpyrene‐1,6‐diamine (BD2) exhibits significantly less EQE roll‐off. This article provides valuable insights into the substitution‐based modification strategy for optimizing blue light performance in OLED applications.

Development of red to blue emissive fluorescent materials for cyanide ion sensing and single-component inks in digital printing application

The work designed and described here is for the effective recognition of cyanide ion. A novel core (PC) with coumarin moiety as a signaling unit and pyridinium as an acceptor unit and these moieties linked by π-conjugation. In which CN− ion binds in the pyridine ring via nucleophilic addition and produces changes that are captured by different techniques to prove its sensing efficiency. The probe displays a visual color variation to pale orange from purple and also exhibits blue fluorescence from red fluorescence upon cyanide addition. The probe PC sensing ability towards CN− ion has been confirmed by various spectral measurement. In UV–visible technique, a blue shift was observed by the probe with CN− ion. In fluorescence measurements, a peak appeared at 704 nm, which corresponds to the probe encountering a peak enhancement with the added cyanide ion. The binding stoichiometric ratio among the probe and CN− ion is to be 1:1 in jobs method. The probes detection limit and binding constant were calculated to be 0.39 nM and 7.07x104 M. The probe is used as a single component ink and injected into a cartridge and printed on paper which is used as a tool to detect cyanide in water. Besides, the probe successfully senses cyanide ion in various water samples.

Preparation of dispersible carbon nitride powder and fabrication of its thin films by wet-process

To establish a low-cost and environment-friendly method for producing blue fluorescent materials and their thin films, we investigated the conditions for synthesizing graphitic carbon nitride (g-C3N4) powder from urea and melamine. We found that urea can be used to synthesize g-C3N4 at lower annealing temperatures than melamine. The synthesized g-C3N4 powder showed good dispersibility in deionized water and methanol, and it was found that relatively uniform g-C3N4 thin films could be obtained by low-speed spin-coating, especially with highly volatile methanol dispersions. These results indicate that blue fluorescent thin films can be fabricated using a wet process at room temperature.

Blue fluorescent waterborne polyurethane‐based transition metal complexes with antibacterial activity

AbstractEfficient and stable blue fluorescent materials are the key components of light‐emitting devices and have received wide attention. Herein, transition metal complexes Zn(5‐AQ)2, Cu(5‐AQ)2, and Cd(5‐AQ)2 are prepared by using 5‐aminoquinoline (5‐AQ) as ligand and Zn2+, Cu2+, and Cd2+ as the central ions, respectively. Then, waterborne polyurethane (WPU)‐based transition metal complexes Zn(5‐AQ)2‐WPU, Cu(5‐AQ)2‐WPU, and Cd(5‐AQ)2‐WPU with different emission wavelengths of blue fluorescence are prepared by bonding Zn(5‐AQ)2, Cu(5‐AQ)2, and Cd(5‐AQ)2 to polyurethane chains as chain extenders, respectively. Noteworthily, with the increase of transition metal ion radius (Zn2+ < Cu2+ < Cd2+), the fluorescence emission wavelengths of the complexes showed different degrees of blue‐shift, and the blue‐shifted wavelengths showed a decreasing trend. Importantly, their fluorescence colors are blue‐shifted from blue‐green to blue with different emission wavelengths after accessing the polyurethane backbone, which has potential applications in the field of tuning white LED materials. The thermal decomposition temperatures of Zn(5‐AQ)2‐WPU, Cu(5‐AQ)2‐WPU, and Cd(5‐AQ)2‐WPU are above 220°C with good thermal stability, and their fluorescence lifetimes are prolonged by 8.817, 8.896, and 6.489 ns, respectively, compared with the complexes. Furthermore, WPU transition metal complexes with water as a dispersive medium have an antibacterial efficiency of up to 100% against Escherichia coli, which is an environmentally friendly antibacterial material with broad application prospects.

P‐214: TADF/Fluorescent Hybrid WOLED Device with Adjustable Color Temperature

Although the tandem WOLED have the potential of high efficiency and long lifetime, the high voltage of tandem structure usually limits its application inAR/VR products. To achieve low voltage WOLED, it is necessary to develop single structure. Most of the reported single WOLED with the use of TADF materials show a relatively large CIE coordinates. In this work, we use the combination of blue fluorescence and yellow TADF materials with a 1‐2 nm p‐type interlayer material between them. The energy is transferred from blue fluorescence to TADF. And finally, the single WOLED with tunable color temperature was realized. The CIE coordinates can be tuned from the warm white point of (0.313, 0.323) to the cold white point of (0.285, 0.279). The roll‐off of efficiency from 240 nit to 3000 nit is lower than 10%, and the lifetime (LT95) can reach 1300 h at 1000 nit.

Synthesis and characterization of a blue host polymer incorporating a chrysene moiety for solution-processed OLEDs

We synthesized two blue fluorescent materials, 6-(3-vinylphenyl)chrysene (St-C) and 6,12-bis(3-vinylphenyl)chrysene (St-C-St), for the first time, incorporating styrene into a chrysene core. These materials were polymerized via radical polymerization, resulting in the formation of polymeric blue-emitting materials, Poly 6-(3-vinylphenyl)chrysene (Poly St-C) and Poly 6,12-bis(3-vinylphenyl)chrysene (Poly St-C-St). Poly St-C exhibited deep blue emission at 395 nm in solution state. We fabricated Organic Light-Emitting Diode (OLED) devices, employing Poly St-C as the host material and 6,12-bis[4-(diphenylamino)phenyl]chrysene (TPA-C-TPA) as the dopant. The OLED device displayed electroluminescence (EL) emission in the deep blue region and achieved Commission Internationale de l‘Éclairage (CIE) coordinates of (0.157, 0.078).

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.

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.

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.

Highly efficient and stable blue photoluminescence from environmental-friendly double perovskites

Despite intensive explorations, lead-free, low toxicity, efficient, and stable blue fluorescent materials are still highly desirable. Cs2NaInCl6 double perovskite (DP) is considered as a promising candidate for solid-state lighting due to its low toxicity and good stability. In this work, Mg-doped Cs2NaInCl6 DPs are prepared by a solvothermal method. The Mg2+-doped Cs2NaInCl6 DPs exhibit blue photoluminescence (PL) at about 445 nm with a full-width at half maximum of 58.0 nm, which is independent of the excitation wavelength. The large Stokes shift (129.5 nm), long PL lifetime (10.44 μs), and huge Huang–Rhys factor (40.2) suggest that the blue PL originates from self-trapped excitons. After optimizing the reaction conditions and doping concentration, a high photoluminescence quantum yield of 86.98% is obtained. Moreover, the Mg-doped Cs2NaInCl6 DPs exhibit good resistance to irradiation and moisture, which are expected to remedy the shortage of current blue emitting materials.

A sensitization strategy for highly efficient blue fluorescent organic light-emitting diodes

Highly efficient blue fluorescent materials have recently attracted great interest for organic light-emitting diode (OLED) application. Here, two new pyrene based organic molecules consisting of a highly rigid skeleton, namely SPy and DPy, are developed. These two blue light emitters exhibit excellent thermal stability. The experiment reveals that the full-width at half-maximum (FWHM) of the emission spectrum can be tuned by introducing different amounts of 9,9-diphenyl-N-phenyl-9H-fluoren-2-amine on pyrene units. The FWHM of the emission spectrum is only 37 nm in diluted toluene solution for DPy. Furthermore, highly efficient blue OLEDs are obtained by thermally activated delayed fluorescence (TADF) sensitization strategy. The blue fluorescent OLEDs utilizing DPy as emitters achieve a maximum external quantum efficiency (EQE) of 10.4% with the electroluminescence (EL) peak/FWHM of 480 nm/49 nm. Particularly, the EQE of DPy-based device is boosted from 2.6% in non-doped device to 10.4% in DMAc-DPS TADF sensitized fluorescence (TSF) device, which is a 400% enhancement. Therefore, this work demonstrates that the TSF strategy is promising for highly efficient fluorescent OLEDs application in wide-color-gamut display field.Graphical

Preparation and photoluminescence of GdVO4:Tm3+ blue phosphor for plant lighting

Blue fluorescent materials play an important role in the manufacture of white light-emitting diodes (WLEDs) for plant lighting excited by near-ultraviolet (NUV) chips. In this article, Tm3+ ions were doped into GdVO4 matrix to obtain stronger blue light emission. The phase structure, apparent morphology, and luminescence properties of the prepared samples were characterized and analyzed by x-ray diffractometry (XRD), scanning electron microscopy (SEM), and fluorescence spectrometry. The results showed that GdVO4:Tm3+ blue phosphor could be prepared by the high-temperature solid-phase calcination method at 1100 °C within 2 h. The powder had an approximately spherical shape of about 2 μm, and the excitation and emission peaks were detected at 319 nm in the ultraviolet region and 480 nm in the blue region, respectively. The prepared GdVO4:Tm3+ blue phosphor and a 310 nm deep-ultraviolet chip were successfully assembled to manufacture a WLED device. It is expected that the blue phosphor prepared in this study can be used to assemble WLED devices to obtain efficient lighting.

The positional effect of arylamines on pyrene core in a blue fluorescent dopant significantly affecting the performance of organic light emitting diodes

New blue fluorescent dopant materials based on pyrene moieties were synthesized by variation of the positions of N-phenylnaphthalene-1-amine functional groups to minutely control the molecular geometry and photophysical properties. A blue dopant with the functional groups at the 1, 6 position exhibited the highest photoluminescence quantum yield. 3,8-Diisopropyl-N1,N6-di(naphthalen-1-yl)-N1,N6-diphenylpyrene-1,6-diamine (DI-1,6-DAP) exhibited the best performances with a current efficiency of up to 6.89 cd/A and external quantum efficiency of 5.45% among the new synthetic dopants prepared in this study. In terms of color purity, the case of substituting arylamine groups at the 1,7 position of the pyrene core unit [N1,N7-di(naphthalen-1-yl)-N1,N7-diphenylpyrene-1,7-diamine (1,7-DAP)] was superior to the case of attaching them at the 1,6 position of the same core unit [N1,N6-di(naphthalen-1-yl)-N1,N6-diphenylpyrene-1,6-diamine (1,6-DAP)] (y < 0.098).

Boron-containing thermally activated delayed blue fluorescence materials via donor tuning: A theoretical study

Based on the boron-containing thermally activated delayed fluorescence (TADF) compound p-AC (AC: acridine) 5,9-dioxa-13b-boranaphtho [3,2,1-de] anthracene (a), a series of new TADF molecules b1−b4 were designed via adding two nitrogen atoms at the AC donor part. Density functional theory and time-dependent density functional theory calculations were performed on the frontier orbital energy levels, emission spectra, singlet-triplet states energy gaps (ΔEST), reverse intersystem crossing (RISC) rate constant (kRISC) for compounds a and b1−b4. Our calculation results show that the maximum emission wavelengths of b1−b4 are significantly blue-shifted by 47−125 nm compared with that of a. Molecules b1 and b3 exhibit dark-blue emission, while molecules b2 and b4 display light-blue emission, indicating that these four derivatives could be potential organic light-emitting diode (OLED) candidates with blue-light emitting. Moreover, we found the RISC processes in a, b2, and b4 can occur not only from T1 state to S1 state, but also from T2 state to S1 state significantly, while the RISC processes in b1 and b3 mainly take place via the T2→S1 hot exciton way. Importantly, the T1→S1 kRISC values of b2 and b4 are predicted to be two to three times of that of a, indicating enhanced TADF property. Our results not only provide two promising boron-based TADF candidates (b2 and b4), but also offer useful theoretical basis for the design of blue OLED materials.

Anthracene-based blue fluorescence materials utilized in non-doped OLEDs with high luminance and a low efficiency roll-off

In this work, we designed and synthesized two novel blue-emitting compounds (m-TAC and p-TAC) with a twisted D-π-A configuration by incorporation of 2,4,6-triphenyl-1,3,5-triazine as an acceptor and carbazole as a donor through an anthracene π-spacer. Therein, p-TAC exhibits a hybridized local and charge-transfer (HLCT) characteristic with a sky-blue emission at 462 nm in toluene while m-TAC shows emission maximum at 431 nm. The two compounds exhibit superb thermal stability in the company of a thermal decomposition temperature (Td) as high as 507 and 516 °C. It is noticed that the non-doped devices with m-TAC and p-TAC as blue emitters display a turn-on voltage (Von) of 3.2 V and achieve sky-blue emission at 460 and 476 nm. In particular, the optimized device based on p-TAC realizes a maximum luminance above 10 000 cd m−2 and the maximum external quantum efficiency (EQEmax) reaching 5.03%. As a sky-blue HLCT emitter, p-TAC reveals high-efficiency electroluminescence (EL) performance, providing a new insight for further industrial applications.

Flexible White Lighting Fabricated With Quantum Dots Color Conversion Layers Excited by Blue Organic Light-Emitting Diodes

In this study, HATCN is coated on flexible PET/indium tin oxide (ITO) substrate as a modified layer and a hole injection layer to improve the hole injection from ITO. Then a blue organic light emitting diode (OLED) can successfully be fabricated without a surface treatment procedure (O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> plasma or UV Ozone treatment). The new blue TADF series fluorescent material is employed as emitting layer with a luminescence wavelength of 456 nm. Also, it has a narrow full width at a half maximum (FWHM) of 26 nm featuring excellent color chromaticity. Quantum dot (QD) photoresist is a perfect color conversion material featuring good color adjustability, narrow emission spectrum, high luminous efficiency, and simple spin-coating processes. In this study, the photoresist mixed with green and red quantum dots is used as a color conversion layer (CCL), and a blue OLED is utilized to excite green and red CCL. To test the material of QD photoresist, it is coated on the substrate of another piece of glass first and then the blue OLED is utilized to remotely excite green and red QD CCL. The fluorescence characteristic of QD photoresist is explored to acquire a spectrum of 528 nm and 620 nm. In the device structure of a blue OLED, the electron-and hole-only current density is compared and the hole transport layer TAPC thickness is adjusted to improve the luminance and efficiency. Finally, green and red quantum dot photoresist is mixed using a proper ratio and then directly coated on the back of the PET/ITO substrate. Furthermore, the thickness of the QD photoresist is adjusted to increase the QD excited fluorescence. The blue OLED and QD CCL was integrated to generate three primary colors, i.e., blue, green, and red. Finally, a flexible white OLED lighting panel is successfully fabricated using simple processes. Moreover, it features high-spectrum stability. The CIE coordinates will not drift with bias, thus, it can resist the voltage variation.

High-quality all-fluorescent white organic light-emitting diodes obtained by balancing carriers with hole limit layer

Broad-spectrum white organic light-emitting diodes (WOLEDs) based on all-fluorescent materials with excellent color stability were realized by precisely optimizing the doping concentrations of guests and the thickness of each functional layer. High-efficiency blue fluorescent emissive material 9,10-bis[4-(6-methylbenzothiazol-2-yl)phenyl]anthracene (DBzA) was selected as blue emitter and doped into first light emitting layer (EML), while red-emitting dopant 4-(dicyanomethylene)-2-tert-butyl-6-(1,1,7,7-tetramethyljulolidn-4-yl-vinyl)- 4H-pyran (DCJTB) was doped into green-emitting host material tris(8-hydroxyquinoline) aluminum (Alq3) as the second EML. Thin hole limit layer (HLL) was inserted to balance carriers' distribution within the two EMLs and to modulate the luminous intensity ratio of different emissions. Finally, the optimal WOLED exhibited the maximum current efficiency of 9.34 cd/A, power efficiency of 10.06 lm/W, brightness up to 29,364 cd/m2 and turn-on voltage of only 2.7 V. In addition, this device displayed stable Commission International de I'Eclairage coordinates from (0.339, 0.382) to (0.324, 0.354) with increasing current density. The highest color rendering index and corresponding correlated color temperature reach 85 and 5492 K, respectively, and the T50 lifetime reaches 7912 h. The achievement of these results fully exhibits the effectiveness of the HLL in improving spectral stability and operation lifetime.

Biindenophenanthrene derivatives as non-doped blue fluorescent materials for organic light-emitting diodes

We designed and synthesized biindenophenanthrene derivatives for blue fluorescent organic light-emitting diodes (OLEDs) materials to overcome the disadvantages of blue emitter caused by the wide band gap. To demonstrate the electroluminescence (EL) properties, the OLEDs devices were fabricated in the following sequence: indium-tin-oxide (180 nm)/4,4’,4’’-tris[2-naphthyl(phenyl)amino (30 nm)/4,4’-bis(N-(1-naphthyl)-N-phenylamino) biphenyl (20 nm)/Blue emitting materials (20 nm)/Bathophenanthroline (30 nm)/lithium quinolate (2 nm)/Al (100 nm). Device A that using 13,13,13',13'-tetramethyl-13H,13'H-11,11'-biindeno[1,2-l]phenanthrene in emitting layer showed luminous efficiency, power efficiency, and external quantum efficiency of 1.72 cd/A, 0.58 lm/W, 1.03% at 20 mA/cm2 with Commission Internationale d’Énclairage (CIE) coordinates of (0.15, 0.23) at 8.0 V.

7,7-Dimethyl-9-(10-phenylanthracen-9-yl)-7H-Benzo[b] Fluoreno[3,4-d]Thiophene Derivatives for Blue Fluorescent Organic Light-Emitting Diodes.

In this study, we designed and synthesized two blue fluorescence materials using 7,7-dimethyl-9-(10-phenylanthracen-9-yl)-7H-benzo[b]fluoreno[3,4-d]thiophene substituted anthracene derivatives. To characterize their electroluminescent properties, we fabricated the OLED devices using these two emitting materials. Particularly, a device using 7,7-dimethyl-9-(10-phenylanthracen-9-yl)-7Hbenzo[ b]fluoreno[3,4-d]thiophene showed maximum values of luminous efficiency, power efficiency, and external quantum efficiency of 2.42 cd/A, 1.48 lm/W, 3.08% at 20 mA/cm2, respectively with CIE (x, y) coordinates of (0.15, 0.09) at 8.0 V.