Blue Host Research Articles

Prussian Blue Analogue Framework Hosts for Li–S Batteries

Prussian Blue Analogue Framework Hosts for Li–S Batteries

Unveiling the role of external electric field on the charge transport and excited-state properties of high T1 host for blue OLED devices

Density functional theory (DFT) and time-dependent DFT (TDDFT) calculations were performed to understand the effect of the external electric field (EEF) on the reorganization (λ) and the lowest triplet excited-state (T1) energies of high T1 blue host materials. Depending on the direction and the strength of the external electric field (EEF), the positive and negative changes of hole and electron λ(h and λ e) values were found in these materials. More importantly, λ e seems to be more sensitive than λ h values under the EEF. It is also noticed that the calculated T1 energies are meaningfully changed in the application of EEFx and EEFy. In contrast, the effect of EEFz on the T1 energies can be negligible. From the results of theoretical investigation, the obvious evidence related to the influence of EEF on the charge transport and excited-state properties of high T1 blue host materials were obtained. In the present work, we expect that our theoretical study will provide new insight into understanding the influence of EEF as a key player in manipulating essential properties of the high T1 blue host material during the electrical operation.

Lopsided distribution of MATLAS and ELVES dwarf satellite systems around isolated host galaxies

The properties of satellite dwarf galaxies provide important empirical insights for verifying cosmological models on galaxy scales. Their phase-space correlations, in particular, offer interesting insights into a broad range of models, since they are dominated by gravity and are largely independent of the specific dark matter flavor or baryonic processes that are considered. Next to the much-debated planes-of-satellites phenomenon, the lopsided distribution of satellites relative to their host galaxy has been studied observationally and in cosmological simulations. The degree to which observed lopsidedness is consistent with expectations from simulations is still unclear. We quantified the level of lopsidedness in isolated observed satellite systems under six different metrics. We studied 47 systems from the MATLAS survey beyond the local volume (LV) as well as 21 LV satellite systems from the ELVES survey. The satellite systems are complete to an estimated absolute magnitude of M ∼ −9. We find that the so-called wedge metric, counting the number of dwarfs in wedges with varying opening angles, is best suited to capture a system’s overall lopsidedness. Under this metric, our analysis reveals that ∼16 percent of the tested satellite systems exhibit a statistically significant degree of lopsidedness when compared to systems with randomly generated satellite position angles. This presents a notable excess over the expected 5% (2σ level) of significantly lopsided systems in a sample with no overall inherent lopsidedness. To gain the most rounded picture, however, a combination of metrics that are sensitive to different features of lopsidedness should be used. Combining all tested metrics, the number of significantly lopsided systems increases to ∼21 percent. Contrary to recent results from the literature, we find more lopsided systems among the red early-type galaxies in the MATLAS survey compared to the mostly blue late-type hosts in ELVES. We further find that satellite galaxies at larger distances from the host, potentially recently accreted, are likely the primary contributors to the reported excess of lopsidedness. Our results set the groundwork that allows a comparison with similar systems in cosmological simulations to assess the consistency with the standard model.

Enabling robust near-infrared afterglow polymers through cascade energy transfer

Near-infrared afterglow materials, which can significantly reduce background fluorescence and improve penetration in living organisms, are vital for precision imaging. However, the practicability of near-infrared afterglow materials has been hindered by their short lifetime and low luminescence quantum efficiency. Herein, we propose an effective strategy for doping water-soluble afterglow polymer host materials with fluorescent dyes, leveraging the step-by-step Förster energy transfer principle to realize near-infrared afterglow. Benefiting from the ultralong lifetime of 4.2 s and high quantum efficiency of 20.1 % for the blue host PAMCz as well as efficient cascade energy transfer efficiency of 83.3 %, the developed NIR afterglow exhibits luminescence peaked at 750 nm, a lifetime of 1.4 s, and a quantum efficiency of 17.1 %. A successful demonstration of near-infrared afterglow biological imaging with a penetration depth of 3.4 mm and signal-to-background ratio of 48.3, has been established. These advancements expand the scope of near-infrared afterglow materials by combining an ultralong lifetime with high quantum efficiency, providing a roadmap for designing robust near-infrared materials.

Highly Efficient Blue Host Compound Based on an Anthracene Moiety for OLEDs

We designed and successfully synthesized a novel anthracene-based host material, 10-(4-(naphthalen-1-yl)phenyl)-9-(naphthalen-3-yl)anthracene (2-NaAn-1-PNa). The 2-NaAn-1-PNa exhibited a PL max at 440 nm in film state and demonstrated a wide band gap of 2.95 eV, indicating its suitability as a blue host material. In an OLED device using 2-NaAn-1-PNa as the host and 3Me-1Bu-TPPDA as the dopant, real blue emission was achieved with an electroluminescence maximum (ELmax) at 460 nm and Commission Internationale de L’Eclairage coordinates of (0.133, 0.141). The device exhibited excellent EL characteristics, with an external quantum efficiency of 8.3% and a current efficiency of 9.3 cd/A at 10 mA/cm2. Furthermore, the efficiency roll-off was limited to only 1.9% up to 4000 nits, demonstrating exceptional performance.

P‐253: Late‐News Poster: The Evaluation on the Stability of Electroluminescent Materials Using Polaron Pair Formation Kinetics

We developed the method for evaluation of the stability of electroluminescent materials by using QEMS (quantum efficiency measurement system). Relative PL (photoluminescence) intensity decay of BDs (blue dopants) with BHs (blue hosts) in solution under UV light irradiation were measured and the rate constants for polaron pair formation by electron transfer were determined through first‐order kinetics analyses. The rate constants of polaron pair formation (6.487E‐04 –1.805E‐03 min‐1 ) were inversely proportional to the lifetime of OLED (organic light‐emitting diode) devices. We expect that this evaluation method can be applied to the development of new OLED materials and longer lifetime OLED devices.

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).

Rational design of blue TADF host of various polarity according to cyano- group applicable to blue thermally activated delayed fluorescence emitter

Although remarkable progress has been made in the field of blue organic light-emitting diodes (OLEDs), many challenges persist. In particular, the emitting material layer of an OLED is composed of a host and a dopant, and the host material has a significant influence on the device efficiency and lifetime along with the dopant. Therefore, in this study, 9-(2′-(dibenzo[b,d]furan-4-yl)-[1,1′-biphenyl]-3-yl)-9H-carbazole, 3′-(9H-carbazol-9-yl)-2-(dibenzo[b,d]furan-4-yl)-[1,1′-biphenyl]-3-carbonitrile, and 3′-(9H-carbazol-9-yl)-2-(dibenzo[b,d]furan-4-yl)-[1,1′-biphenyl]-4-carbonitrile were synthesised to investigate the changes in the device efficiency and lifetime through various properties such as the polarity of the host molecule and anionic bond dissociation energies (BDEs) according to the substitution position of the CN group. In addition, 2,4,6-tris(2-(3,6-di-tert-butyl-9H-carbazol-9-yl)phenyl)-1,3,5-triazine, a blue thermally activated delayed fluorescence dopant, was synthesised and evaluated. The roll-off at 5000 nit decreased from 30.2% to 21.9% depending on the polarity of the host molecule, whereas the lifetime increased from 7.95 to 15.5 h according to the anionic BDE of blue thermally activated delayed fluorescence hosts.

Novel blue multiresonance thermally activated delayed fluorescence host materials, including Ge-based bulky groups

We synthesized three materials, namely, TDBA-Ge, mTDBA-Ge, and mTDBA-2Ge, as blue host emitters. Among the three materials, mTDBA-2Ge exhibited the highest efficiency, with an EQEmax of 24.41%.

Enhanced Horizontal Dipole Orientation by Novel Penta-Helicene Anthracene-Based Host for Efficient Blue Fluorescent OLEDs.

Due to the relatively low photoluminescence quantum yield (PLQY) and horizontal dipole orientation of doped films, anthracene-based fluorescent organic light-emitting diodes (F-OLEDs) have faced a great challenge to achieve high external quantum efficiency (EQE). Herein, a novel approach is introduced by incorporating penta-helicene into anthracene, presented as linear-shaped 3-(4-(10-phenylanthracen-9-yl)phenyl)dibenzo[c,g]phenanthrene (BABH) and 3-(4-(10-(naphthalen-2-yl)anthracen-9-yl)phenyl)dibenzo[c,g]phenanthrene (NABH). These blue hosts exhibit minimal intermolecular overlap of π-π stacking, effectively suppressing excimer formation, which facilitates the effective transfer of singlet energy to the fluorescent dopant for PLQY as high as 90%. Additionally, the as-obtained two hosts of BABH and NABH have effectively demonstrated major horizontal components transition dipole moments (TDM) and high thermal stability with glass transitional temperature (Tg) surpassing 188°C, enhancing the horizontal dipole orientation of their doped films to be 89% and 93%, respectively. The OLEDs based on BABH and NABH exhibit excellent EQE of 10.5% and 12.4% at 462nm and device lifetime up to 90% of the initial luminance over 4500h at 100cdm-2, which has firmly established them as among the most efficient blue F-OLEDs based on anthracene to date to the best knowledge. This work provides an instructive strategy to design an effective host for highly efficient and stable F-OLEDs.

Increasing Chemical Diversity of B2 N2 Anthracene Derivatives by Introducing Continuous Multiple Boron-Nitrogen Units.

Increasing the chemical diversity of organic semiconductors is essential to develop efficient electronic devices. In particular, the replacement of carbon-carbon (C-C) bonds with isoelectronic boron-nitrogen (B-N) bonds allows precise modulation of the electronic properties of semiconductors without significant structural changes. Although some researchers have reported the preparation of B2 N2 anthracene derivatives with two B-N bonds, no compounds with continuous multiple BN units have been prepared yet. Herein, we report the synthesis and characterization of a B2 N2 anthracene derivative with a BNBN unit formed by converting the BOBN unit at the zigzag edge. Compared to the all-carbon analogue 2-phenylanthracene, BNBN anthracene exhibits significant variations in the C-C bond length and a larger highest occupied molecular orbital-lowest unoccupied molecular orbital energy gap. The experimentally determined bond lengths and electronic properties of BNBN anthracene are confirmed through theoretical calculations. The BOBN anthracene organic light-emitting diode, used as a blue host, exhibits a low driving voltage. The findings of this study may facilitate the development of larger acenes with multiple BN units and potential applications in organic electronics.

Increasing Chemical Diversity of B2N2 Anthracene Derivatives by Introducing Continuous Multiple Boron‐Nitrogen Units

AbstractIncreasing the chemical diversity of organic semiconductors is essential to develop efficient electronic devices. In particular, the replacement of carbon‐carbon (C−C) bonds with isoelectronic boron‐nitrogen (B−N) bonds allows precise modulation of the electronic properties of semiconductors without significant structural changes. Although some researchers have reported the preparation of B2N2 anthracene derivatives with two B−N bonds, no compounds with continuous multiple BN units have been prepared yet. Herein, we report the synthesis and characterization of a B2N2 anthracene derivative with a BNBN unit formed by converting the BOBN unit at the zigzag edge. Compared to the all‐carbon analogue 2‐phenylanthracene, BNBN anthracene exhibits significant variations in the C−C bond length and a larger highest occupied molecular orbital–lowest unoccupied molecular orbital energy gap. The experimentally determined bond lengths and electronic properties of BNBN anthracene are confirmed through theoretical calculations. The BOBN anthracene organic light‐emitting diode, used as a blue host, exhibits a low driving voltage. The findings of this study may facilitate the development of larger acenes with multiple BN units and potential applications in organic electronics.

4.2: A 9‐(4‐diphenylphosphinylphenyl)anthracene derivative as a blue emitter host and a hole‐blocking layer in Deep Blue OLEDs

We investigated 10‐(4‐phenylphenyl)‐9‐(3‐diphenylphosphinyl‐phenyl)anthracene as a host material in the emitting layer and a hole‐blocking layer in deep blue OLEDs, respectively. By contrast, introducing a thin layer of this triphenylphosphine oxide moiety‐modified anthracene derivative as the hole blocker exhibits a maximum external quantum efficiency of 5.49% with CIE (0.126, 0.118) and in particular, high device stability with lifetime LT95 of ca. 540 h @ 1000 cd m–2.

Lopsided Satellite Distributions around Isolated Host Galaxies in a ΛCDM Universe

A recent observational study found that the projected spatial distributions of the satellites of bright, isolated host galaxies tend to be lopsided with respect to the locations of the hosts. Here, we examine the spatial distributions of the satellites of a large number of bright, isolated host galaxies that were obtained from mock redshift surveys of a Λ-cold dark matter (ΛCDM) simulation. Host galaxies and their satellites were identified using selection criteria that are identical to those used in the observational study, allowing for a direct comparison of the results for the simulated and observed systems. To characterize the spatial distribution of the satellites, we adopt two statistics: (1) the pairwise clustering of the satellites and (2) the mean resultant length. In agreement with the observational study, we find a strong tendency for satellites in the simulation to be located on the same side of their host, and the signal is most pronounced for the satellites of blue hosts. These lopsided satellite distributions are not solely attributable to incompleteness of the observed satellite catalog or the presence of objects that have been falsely identified as satellites. In addition, satellites that joined their hosts’ halos in the distant past (≳8 Gyr) show a pronounced lopsidedness in their spatial distributions and, therefore, the lopsidedness is not solely attributable to the late-time accretion of satellites.

Cross-Hemispheric Genetic Diversity and Spatial Genetic Structure of Callinectes sapidus Reovirus 1 (CsRV1).

The movement of viruses in aquatic systems is rarely studied over large geographic scales. Oceanic currents, host migration, latitude-based variation in climate, and resulting changes in host life history are all potential drivers of virus connectivity, adaptation, and genetic structure. To expand our understanding of the genetic diversity of Callinectes sapidus reovirus 1 (CsRV1) across a broad spatial and host life history range of its blue crab host (Callinectes sapidus), we obtained 22 complete and 96 partial genomic sequences for CsRV1 strains from the US Atlantic coast, Gulf of Mexico, Caribbean Sea, and the Atlantic coast of South America. Phylogenetic analyses of CsRV1 genomes revealed that virus genotypes were divided into four major genogroups consistent with their host geographic origins. However, some CsRV1 sequences from the US mid-Atlantic shared high genetic similarity with the Gulf of Mexico genotypes, suggesting potential human-mediated movement of CsRV1 between the US mid-Atlantic and Gulf coasts. This study advances our understanding of how climate, coastal geography, host life history, and human activity drive patterns of genetic structure and diversity of viruses in marine animals and contributes to the capacity to infer broadscale host population connectivity in marine ecosystems from virus population genetic data.

Recent Advances in Triplet–Triplet Annihilation-Based Materials and Their Applications in Electroluminescence

Efficient and stable blue organic light-emitting devices (OLEDs) represent one of the most important components in future solid-state lighting and full color displays. Although red and green OLEDs have been successfully commercialized, it remains challenging to realize blue OLEDs showing high efficiency and high stability simultaneously, restricting their commercialization. Triplet–triplet annihilation (TTA)-based materials have been emerging as a new category of electroluminescent or host materials with promising potential for highly efficient and stable blue devices due to their appealing photophysical properties (e.g., ability to generate emissive singlet excited states through TTA process, high photoluminescence quantum yield, ease of molecular design, etc.). Recently, research on TTA-based materials toward high-performance blue OLEDs has received an increasing attention. In this review, recent research advances on the molecular design strategies, photophysical properties of TTA-based materials (both blue emitters and host materials), mechanism of TTA-based electroluminescence, as well as their OLED applications are presented comprehensively. Moreover, potential perspectives with future research opportunities in this field are also described. We believe that the emerging TTA-based materials will bring more opportunities for developing a large family of novel photofunctional materials showing appealing and tunable photophysical properties, thus providing new opportunities for high-efficiency and stable blue electroluminescence in the future.

Thermally activated delayed fluorescence dendrimers with AIE property and functional dendrons for high-efficiency solution-processed white OLEDs

Thermally activated delayed fluorescence (TADF) materials with encapsulation dendrons have exhibited superior advantages in the solution-processed OLEDs. Herein, we utilized electron-donating carbazole and electron-withdraw phenylbenzimidazole as the peripheral wrapping unit to design and synthesize two TADF materials, TRZCz-Cz and TRZCz-Bz, to discuss the distinction about different encapsulations for one identical emissive core. The photophysical investigation demonstrate that both compounds have small ΔE ST and clearly aggregation-induced enhancement (AIE) properties, which are benefit for enhancing the exciton unitization of electroluminescence devices. Despite similar characters in photophysical property, the blue phosphorescence OLEDs host with TRZCz-Cz obtain the maximum current efficiency and external quantum efficiency of 38.6 cd A −1 and 18.4%, respectively, which far exceed TRZCz-Bz based one. Thanks to the high performance of blue device, the fully phosphorescent white OLEDs with Ir(MDQ) 2 (acac) as red phosphorescent dopant achieves the maximum luminescence, current efficiency, external quantum efficiency as high as 12874 cd m −2 , 33.8 cd A −1 and 16.5%, respectively, which are among the highest efficiency of solution-processed white OLEDs. Moreover, the hybrid white OLEDs with TADF as blue host and red phosphor as dopant was also achieved with a low turn-on voltage of 3.2 V, and more standard white emission with CIE coordinate of (0.34,0.33). Thus, this work significantly extends the range of AIE TADF materials and paves the useful way for the fabrication of high efficiency white OLEDs through solution-process. • The optimized wrapping unit enhance the device performance almost two times higher. • The TADF host ensure the solution-processed blue phosphorescence OLEDs with the EQE max of 18.4%. • Both the fully phosphorescent and hybrid white OLEDs achieves high luminescence and stable color purity.

Supramolecular [2]pseudo-rotaxane polymer containing blue anthracene donor guest and green naphthalimide acceptor host as a FRET-ON sensor for hydrogen sulfide detection

A supramolecular host-guest [2]pseudo-rotaxane polymer containing blue-emissive (λem = 425 nm) anthracene-based di-topic donor guest (AN-G) and green-emissive (λem = 530 nm) napthalimide-based di-topic acceptor host (NP–H) after hydrogen sulfide (HS− anion) detection in semi-aqueous media was developed in this study. Towards HS− detection, the bi-fluorophoric [2]pseudo-rotaxane polymer possessed the best FRET process in the THF/Water solution (60% H2O, v/v), which was confirmed by TRPL measurements with the shortest lifetime of 1.1 ns and FRET efficiency of 81.7% in comparison with the longer lifetime of 6.0 ns for mono-fluorophoric [2]pseudo-rotaxane polymer analogue before detection of HS−. The 1:1 host–guest molar ratio and the formation of the [2]pseudo-rotaxane polymer can be further verified using 1H NMR complexation and DOSY experiments. The effects of pH and temperature were also investigated to find that an efficient FRET process of the host-guest could occur at lower and neutral pH values (i.e., pH = 1–9) and in the normal temperature range of 25–40 °C. As the napthalimide can react with HS− anion to induce green turn-on emission behavior, the napthalimide-based mono-fluorophoric guest could detect HS− anion by turn-on photoluminescence with a corresponding limit of detection (LOD) value of 1.04 μM, which was also confirmed to possess a very high selectivity of HS− detection compared with another 23 analytes, including 16 anionic species. In contrast, the optimum LOD value of 0.30 μM for bi-fluorophoric host-guest polymer as a FRET-ON sensor material towards HS− detection was achieved due to the ratiometric emission of distinct color change from blue donor to green acceptor. Therefore, host-guest [2]pseudo-rotaxane polymer can be employed for the future bio-imaging applications of HS− anion detection in living cells.

O2-induced emission color changing/sensing via the combination of red-emitting COF and blue-emitting halogen-bridging Cu(I) phosphor: In-situ synthesis and performance

Covalent organic frameworks (COFs) have shown virtues of structural diversity and porous diversity, due to their versatile organic building blocks. These advantages make COFs a promising host for O2 gas sensors. In this work, a porous COF (denoted as COF-X, X = Br or Cl) having halogen ions (Br or Cl ions) in its micropores was firstly synthesized as host, then Cu clusters [Cu2(PPh3)3X2] were in-situ synthesized. The obtained composite structure was discussed in detail focusing on its photophysical parameters and optical oxygen sensing performance. Probe doping ratio was determined as 2:1 (C162H120N18O12X4@C54H45X2Cu2P3, X = Br or Cl). Host COF-X showed red emission around 628 nm, while probe Cu2(PPh3)3X2 exhibited blue emission around 436 nm with lifetime of 5.21 μs and quantum yield of 0.41 under pure N2 atmosphere. Upon pure O2 atmosphere, probe Cu2(PPh3)3Br2 lifetime and quantum yield were decreased to 1.16 μs and 0.09. Probe emission intensity followed a linear calibration curve with maximum sensitivity of 20.25 (a.u.) and response/recovery time of 9/41 s. This sensitivity was by far the highest one among phosphorescent Cu(I)-based sensors. The relative emission intensity variation between dopant blue emission and host red emission led to an emission color change between blue (under pure N2 atmosphere) and red (under pure O2 atmosphere).

The Distribution of Satellite Galaxies in the IllustrisTNG100 Simulation

We investigate the spatial distribution of the satellites of isolated host galaxies in the IllustrisTNG100 simulation. In agreement with a previous, similar analysis of the Illustris-1 simulation, the satellites are typically poor tracers of the mean host mass density. Unlike the Illustris-1 satellites, here the spatial distribution of the complete satellite sample is well fitted by an NFW profile; however, the concentration is a factor of ∼2 lower than that of the mean host mass density. The spatial distributions of the brightest 50% and faintest 50% of the satellites are also well fitted by NFW profiles, but the concentrations differ by a factor of ∼2. When the sample is subdivided by host color and luminosity, the number density profiles for blue satellites generally fall below the mean host mass density profiles, while the number density profiles for red satellites generally rise above the mean host mass density profiles. These opposite, systematic offsets combine to yield a moderately good agreement between the mean mass density profile of the brightest blue hosts and the corresponding number density profile of their satellites. Lastly, we subdivide the satellites according to the redshifts at which they joined their hosts. From this, we find that neither the oldest one-third of the satellites nor the youngest one-third of the satellites faithfully trace the mean host mass density.