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Nanostructured ionic compounds have driven major technological advancements in displays, photovoltaics, and catalysis. Current research focuses on refining the chemical composition of such compounds. In this study, a strategy for creating stoichiometrically well‐defined nanoscale multiple‐cation systems, where the atomically precise structure maximizes the synergistic cooperation between cations at the atomic scale is reported. The unprecedented construction of Heusler‐type PtRuP2 double‐walled nanotubes through sequential anion/cation exchange reactions is demonstrated. The PtRuP2 catalyst exhibits record‐high catalytic performance and durability for the hydrogen evolution reaction (HER) in alkaline electrolytes and anion‐exchange membrane water electrolyzers. The investigations highlight the crucial role of Pt/Ru dual centers, providing multiple active sites that accelerate the HER kinetics within a single phosphide material, in the sequential operation of H2O activation/dissociation at Ru and H2 production at adjacent Pt sites. These findings open new avenues for optimizing ionic compound‐based HER electrocatalysts, offering platinum‐metal alternatives in acidic and alkaline media. [ABSTRACT FROM AUTHOR]

Repetitive stimulation procedures are used in neuromodulation techniques to induce persistent excitatory or inhibitory brain activity. The directivity of modulation is empirically regulated by modifying the stimulation length, interval, and strength. However, bidirectional neuronal modulations using ultrasound stimulations are rarely reported. This study presents bidirectional control of epileptiform activities with repetitive transcranial‐focused ultrasound stimulations in a rat model of drug‐induced acute epilepsy. It is found that repeated transmission of elongated (40 s), ultra‐low pressure (0.25 MPa) ultrasound can fully suppress epileptic activities in electro‐encephalography and cerebral blood volume measurements, while the change in bursting intervals from 40 to 20 s worsens epileptic activities even with the same burst length. Furthermore, the suppression induced by 40 s long bursts is transformed to excitatory states by a subsequent transmission. Bidirectional modulation of epileptic seizures with repeated ultrasound stimulation is achieved by regulating the changes in glutamate and γ‐Aminobutyric acid levels, as confirmed by measurements of expressed c‐Fos and GAD65 and multitemporal analysis of neurotransmitters in the interstitial fluid obtained via microdialysis. [ABSTRACT FROM AUTHOR]

The popularly used global, meta‐GGA, and range‐separated hybrid DFT functionals are examined to compare the predictive qualities of singlet excited state (S1) properties in HLCT materials. Among these hybrid DFT functionals, it is clarified that both M06 and LC‐ω*HPBE functionals show quantitatively and qualitatively excellent predictions of absorption energies, compared to experiments. However, a discrepant behavior in predicting the emission energy is found that LC‐ω*HPBE functional obviously predicts more accurate emission energy than M06 functional. Also, the calculated τs values by means of M06 and LC‐ω∗HPBE functionals show that LC‐ω∗HPBE functional gives quantitatively and qualitatively superior prediction. Consequently, it is suggested that LC‐ω*HPBE functional should be used to conduct the essential photo‐physical properties of HLCT materials in S1 state. [ABSTRACT FROM AUTHOR]

Electron leakage is one of the most critical factors for the degradation of blue fluorescent organic light‐emitting diodes (FOLEDs), as it occurs when electrons injected from the cathode flow to an electron‐blocking layer (EBL) without being entirely consumed within an emissive layer (EML). To address this issue, this study introduces the concept of an electron leakage‐pathway (ELP). Anthracene core materials, used as hosts for blue FOLEDs were doped in the EBL to prevent its direct damage to the EBL molecules by constructing the ELP. This study shows that using an anthracene core with high bond dissociation energy (BDE) in the anionic state as the ELP is the most effective way to increase the lifetime of the FOLED, demonstrating over 400 h. of LT90 (the time taken for the luminance to decrease to 90% of its initial value), which corresponds to an increase of 33% compared to the lifetime without the ELP. Remarkably, under a commonly used brightness level of 500 cd m−2 in smartphones, an LT50 of over 10 000 h was obtained. Ultimately, this study outlines a strategy for increasing the lifetime of blue FOLEDs through simple modifications to the device structure, without requiring the development of EBL materials or complex device engineering. [ABSTRACT FROM AUTHOR]

Metal–halide perovskite nanocrystals (NCs) have emerged as suitable light‐emitting materials for light‐emitting diodes (LEDs) and other practical applications. However, LEDs with perovskite NCs undergo environment‐induced and ion‐migration‐induced structural degradation during operation; therefore, novel NC design concepts, such as hermetic sealing of the perovskite NCs, are required. Thus far, viable synthetic conditions to form a robust and hermetic semiconducting shell on perovskite NCs have been rarely reported for LED applications because of the difficulties in the delicate engineering of encapsulation techniques. Herein, a highly bright and durable deep‐blue perovskite LED (PeLED) formed by hermetically sealing perovskite NCs with epitaxial ZnS shells is reported. This shell protects the perovskite NCs from the environment, facilitates charge injection/transport, and effectively suppresses interparticle ion migration during the LED operation, resulting in exceptional brightness (2916 cd m−2) at 451 nm and a high external quantum efficiency of 1.32%. Furthermore, even in the unencapsulated state, the LED shows a long operational lifetime (T50) of 1192 s (≈20 min) in the air. These results demonstrate that the epitaxial and hermetic encapsulation of perovskite NCs is a powerful strategy for fabricating high‐performance deep‐blue‐emitting PeLEDs. [ABSTRACT FROM AUTHOR]

Multimaterial emission layer (EML) with host and dopant is known for its advantages in efficiency and lifetime for organic light‐emitting diodes (OLEDs). However, as the compositions and the mixing ratio in the EML diversify, complex device physics and photophysics and complicated fabrication processes become challenging issues. Herein, a new concept to integrate exciton donor (host) and acceptor (dopant) into a single emitting molecule is suggested. 9‐(8,9,10,11‐Tetradeuterospiro[benzo[de]anthracene‐7,9′‐fluoren]‐2'‐yl)‐9H‐carbazole (SBAF‐Cz) and 8,9,10,11‐tetradeutero‐N‐(9,9‐dimethyl‐9H‐fluoren‐2‐yl)‐N‐phenylspiro[benzo[de]anthracene‐7,9′‐fluoren]‐3‐amine (FPA‐SBAF) are used as host and dopant, respectively. By integrating two units, 8,9,10,11‐tetradeutero‐2′‐(9H‐carbazol‐9‐yl)‐N‐(9,9‐dimethyl‐9H‐fluoren‐2‐yl)‐N‐phenylspiro[benzo[de]anthracene‐7,9′‐fluoren]‐3‐amine (FPA‐SBAF‐Cz) is synthesized, and photophysical and electrical properties are characterized. Density functional theory and experimental results consistently reveal that SBAF‐Cz and FPA‐SBAF are photophysically and electrically independent. The electrical properties of FPA‐SBAF‐Cz behave independently, while the photophysical properties are the sum of those of SBAF‐Cz and FPA‐SBAF, which is attributed to the zero radius of intramolecular energy transfer (ZRIET) between donor and acceptor in FPA‐SBAF‐Cz. The single‐component blue OLED with FPA‐SBAF‐Cz exhibits a maximum external quantum efficiency of 4.18%, which is higher than those of OLEDs with SBAF‐CZ:FPA‐SBAF multicomponent EMLs. Surprisingly, the device lifetime to 50% decrease from initial luminance is 114 h in FPA‐SBAF‐Cz OLED, which is 2.2 times longer than that of SBAF‐Cz:FPA‐SBAF OLEDs. [ABSTRACT FROM AUTHOR]

We analyzed the degradation mechanism by deteriorating the exciplex host‐based phosphorescent organic light‐emitting diodes (PhOLEDs) while repeatedly applying voltages in the range of several nA to mA. To identify the most significant degradation factors represented by bleaching, quenching, and charge imbalance, the degradation process was described from various perspectives by the capacitance (C)‐voltage (V) curves (CV), and magneto‐electroluminescence (MEL). Comparing the MEL of the non‐doped and the doped devices, the bleaching of the dopant was confirmed as degradation progressed. Since the highest occupied molecular orbital (HOMO) of the dopant aligns with that of the hole‐transporting layer, the injected holes are easily trapped. As a result, the trap‐induced Shockley‐Read Hall recombination became dominant. Thus, it was identified that the bleaching of the dopant itself acts as the major degradation factor. [ABSTRACT FROM AUTHOR]

A highly efficient anthracene‐based 5‐(4‐(10‐phenylanthracen‐9‐yl)phenyl)‐5H‐benzofuro[3,2‐c]carbazole (ATDBF) with nearly 100% exciton utilization efficiency is developed for highly efficient nondoped blue organic light‐emitting diodes (OLEDs) through inter‐ and intramolecular triplet exciton up‐converting mechanisms. The ATDBF emitter opens hybridized hot excitons, triplet–triplet fusion (TTF), and mixed TTF/hot exciton channels for triplet exciton to singlet exciton conversion. The molecular design adopting a benzofuro[3,2‐c]carbazole (BFCz) donor manages the singlet and triplet excited states for hybridized triplet exciton up‐conversion mechanisms, which enable a high external quantum efficiency (EQE) of 7.93% in the ATDBF blue device with color coordinates of (0.15, 0.06). This is one of the best efficiencies of the nondoped blue OLEDs with a y color coordinate below 0.06. [ABSTRACT FROM AUTHOR]

An electroplex is an excited state charge transfer complex formed between a donor molecule and an acceptor molecule upon electrical excitation. Since the spatial overlap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of electroplex is small likewise exciplex, the energy difference between the singlet and the triplet charge transfer (1CT and 3CT) states can be very small, which facilitate the conversion of triplet excitons into singlet excitons by the assistance of thermal energy and the emission as delayed fluorescence. However, in contrast to exciplex, the detailed analysis of the reverse intersystem crossing (RISC) from 3CT to 1CT and the exciton‐related annihilation processes in electroplex OLEDs have been rarely reported. In this talk, the magnetic field effects (MFEs) on the electroplex host using 2,2'‐di(9H‐carbazol‐9‐yl)‐1,1'‐biphenyl (oCBP) and 9‐(4,6‐bis(3‐(triphenylsilyl)phenyl)‐1,3,5‐triazin‐2‐yl)‐9H‐carbazole (DSiCzTrz) were investigated. Temperature‐dependent MFE measurements revealed that RISC channel co‐exists with the intersystem crossing (ISC) channel and triplet‐polaron quenching process prevails in the electroplex EML. It was also found that 3CT excitons behave as charge scattering sites. [ABSTRACT FROM AUTHOR]

Transition metal phosphides (TMPs) as ever‐evolving electrocatalytic materials have attracted increasing attention in water splitting reactions owing to their cost‐effective, highly active and stable catalytic properties. This work presents a facile synthetic route to NiCoP nanoparticles with Ru dopants which function as highly efficient electrocatalysts for oxygen evolution reaction (OER) in alkaline media. The Ru dopants induced a high content of Ni and Co vacancies in NiCoP nanoparticles, and the more defective Ru doped NiCoP phase than undoped NiCoP ones led to a greater number of catalytically active sites and improved electrical conductivity after undergoing electrochemical activation. The Ru doped NiCoP catalyst exhibited high OER catalytic performance in alkaline media with a low overpotential of 281 mV at 10 mA cm−2 and a Tafel slope of 42.7 mV dec−1. [ABSTRACT FROM AUTHOR]

We have developed the 2,400ppi FMM using UV laser patterning technology and the RGB side‐by‐side OLED micro‐display using Si‐wafer pixel driving circuits. These two key technologies enable us to realize AR devices with ultra‐high pixel resolution, high brightness, long lifetime and high color purity. [ABSTRACT FROM AUTHOR]

Commercialization of energy conversion technologies, such as water electrolysis or fuel cells, has become a common prioritized goal in academia and industry due to the accelerated environmental crisis caused by the rapid increase in demand for fossil fuel‐based energy resources. However, these state‐of‐the‐art technologies require the use of expensive noble metal‐based electrocatalysts, which significantly undermine the feasibility of their commercial success. The introduction of less expensive elements into the noble metal‐based electrocatalysts, namely, doping, has become common in nanocatalysis research because of the lower catalyst preparation costs. Interestingly, recent studies have revealed additional roles of dopants in noble metal catalysts; doping can enhance the catalytic activity and selectivity by modulating the band structure, optimizing the surface energy of the catalysts, controlling the binding strength of adsorbates, and thus affecting the reaction kinetics. Dopants can also intervene in the nanocrystal growth mechanism, leading to shape‐ and phase‐controlled nanocrystals. This review discusses the great versatility of dopants in nanoparticle‐based catalysis in all aspects, from nanocrystal growth to nanocatalyst performance. The future challenges and outlook for dopants in nanocrystals and their applications are further discussed. [ABSTRACT FROM AUTHOR]

We have developed the 2,400ppi FMM using UV laser patterning technology and the RGB side‐by‐side OLED micro‐display using Si‐wafer pixel driving circuits. These two key technologies enable us to realize AR devices with ultra‐high pixel resolution, high brightness, long lifetime and high color purity. [ABSTRACT FROM AUTHOR]

Dissolution of Ir oxides in Ir‐based catalysts, which is closely linked to the catalyst activity and stability toward the oxygen evolution reaction (OER) in acidic media, is a critical unresolved problem in the commercialization of water electrolysis. Doping foreign elements into the Ir oxides can accomplish an optimal combination of Ir oxidation states that is conducive to the leaching‐resistance of active catalytic sites. Here, it is reported that Pt doping into IrOx‐based nanoframe is beneficial in both terms of activity and stability. The Pt‐doped IrOx‐based nanoframe achieves the mass activity of 0.644 A mg−1Ir+Pt at 1.53 VRHE, which is 15‐fold higher than that of the commercial IrO2. During the accelerated durability test, the IrIV‐to‐IrIII ratio of 5 is maintained in the presence of Pt dopant to effectively mitigate the degradation of Ir catalyst, leading to the superb catalyst durability in acidic media. [ABSTRACT FROM AUTHOR]

Considerable attention on sustainable clean energy resources has led to the development of a plethora of catalytic materials, specifically geared toward water electrolysis. Among various developed catalysts, noble‐metal‐based electrocatalysts have shown promising performances for oxygen and hydrogen evolution reactions (OER and HER). However, their high price and scarcity have always been roadblocks to the commercialization of the water‐splitting technology. Recently, transition metal phosphides (TMP) and phosphates (TMPi) have emerged as alternative electrocatalysts for the OER and HER under neutral conditions; water splitting under a neutral conditions eco‐friendly and free of the corrosion issues that are present for acidic or alkaline conditions. Herein, we present the recent progress in TMP(i) based water splitting under neutral conditions, particularly focusing on the synthetic strategies and design concepts for improved catalytic performances. Challenges and outlook for further development of these promising catalysts are also discussed. [ABSTRACT FROM AUTHOR]

We analyzed the change of electrical characteristics of hyper‐fluorescence OLED according to the doping concentration using Modulus spectroscopy. As the concentration of the thermally activated delayed fluorescence (TADF) sensitizer increased, the turn‐on voltage was reduced by forming a conductive path by the sensitizer. However, it was not related to the external quantum efficiency (EQE). The difference between the two trends can be understood from the electrical and photophysical perspectives such as Modulus spectroscopy, EL spectrum and capacitance‐voltage (C‐V) curve. The ratio of 5:1 device with the most suitable doping ratio showed the highest 14.86% of EQE and 46.82 cd/A of current efficiency (CE). The reason for this result is that the distance between the sensitizer and the dopant is most suitable considering the Förster energy transfer (FRET) radius. This contributed to the closest match between the point at which the maximum value of capacitance and the turn‐on voltage of the device in the C‐V curve. [ABSTRACT FROM AUTHOR]

A high triplet energy host is developed using a silane moiety, 9‐(4‐(triphenylsilyl)dibenzo[b,d]furan‐2‐yl)‐9H‐carbazole (SiDBFCz), is designed through extensive density functional theory (DFT) calculations to obtain appropriate hole and electron injection barriers. The chemical hardness and the charge transport characteristics are comprehensively investigated to realize a bipolar host with high triplet energy over 2.9 eV for deep blue phosphorescent organic light‐emitting diodes (PHOLEDs). The synthesized SiDBFCz clearly exhibits the bipolar characteristics especially with emitter molecules doped. An external quantum efficiency over 19 % without any microcavity optimization is achieved thanks to the good charge balance in the SiDBFCz PHOLED. The device lifetime of the SiDBFCz PHOLED is improved more than 1000 %, compared to the unipolar control devices at an initial luminance of 500 cd m−2. The dramatic enhancement of the operational stability of the deep blue PHOLED is also thoroughly investigated in terms of electrochemical stability of host molecules in charged or excited states. The results clearly indicate that the device lifetime is strongly correlated with the bond dissociation energy and the activation energy for the bond dissociation reaction in triplet excited state. [ABSTRACT FROM AUTHOR]

Few studies have directly compared the neural correlates of spatial attention (i.e., attention to a particular location) and nonspatial attention (i.e., attention to a feature in the visual scene) using well-controlled tasks. Here, we investigated the neural correlates of spatial and nonspatial attention in humans using intracranial electroencephalography. The topography and number of electrodes showing significant event-related desynchronization (ERD) or event-related synchronization (ERS) in different frequency bands were studied in 13 epileptic patients. Performance was not significantly different between the two conditions. In both conditions, ERD in the low-frequency bands and ERS in the high-frequency bands were present bilaterally in the parietal cortex (prominently on the right hemisphere) and frontal regions. In addition to these common changes, spatial attention involved right-lateralized activity that was maximal in the right superior parietal lobule (SPL), whereas nonspatial attention involved wider brain networks including the bilateral parietal, frontal, and temporal regions, but still had maximal activity in the right parietal lobe. Within the parietal lobe, spatial attention involved ERD or ERS in the right SPL, whereas nonspatial attention involved ERD or ERS in the right inferior parietal lobule. These findings reveal that common as well as different brain networks are engaged in spatial and nonspatial attention. Hum Brain Mapp 37:3041-3054, 2016. © 2016 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

ABSTRACT The hippocampus plays a key role in the encoding and retrieval of information related to novel environments during spatial navigation. However, the neural basis for these processes in the human hippocampus remains unknown because it is difficult to directly measure neural signals in the human hippocampus. This study investigated hippocampal neural oscillations involved in encoding novel environments during spatial navigation in a virtual environment. Seven epileptic patients with implanted intracranial hippocampal depth electrodes performed three sessions of virtual environment navigation. Each session consisted of a navigation task and a location-recall task. The navigation task consisted of eight blocks, and in each block, the participant navigated to the location of four different objects and was instructed to remember the location of the objects. After the eight blocks were completed, a location-recall task was performed for each of the four objects. Intracranial electroencephalography data were monitored during the navigation tasks. Theta (5-8 Hz) and delta (1-4 Hz) oscillations were lower in the first block (novel environment) than in the eighth block (familiar environment) of the navigation task, and significantly increased from block one to block eight. By contrast, low-gamma (31-50 Hz) oscillations were higher in the first block than in the eighth block of the navigation task, and significantly decreased from block one to block eight. Comparison of sessions with high recall performance (low error between identified and actual object location) and low recall performance revealed that high-gamma (51-100 Hz) oscillations significantly decreased from block one to block eight only in sessions with high recall performance. These findings suggest that delta, theta, and low-gamma oscillations were associated with encoding of environmental novelty and high-gamma oscillations were important for the successful encoding of environmental novelty. © 2014 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Efficient and durable electrocatalysts toward alkaline hydrogen evolution reaction (HER) are of great significance for the widespread application of anion‐exchange membrane water electrolyzer (AEMWE). Numerous single‐phase catalysts, such as Ru2P, have been explored as efficient HER catalysts; however, many have failed to overcome the inherent sluggish kinetics of the two separate steps involved in the alkaline HER: water dissociation and hydrogen production. In this study, density functional theory calculations are conducted to identify promising combinations of Ir2P and Ru2P materials that promote fast cascade water dissociation and H2 production via kinetically favorable hydrogen spillover from the Ru2P surface to the adjacent Ir2P. An unprecedented construction of Ir2P cluster‐decorated Ru2P hollow nanotubes (c‐RP/IP HNTs), which feature a cooperative heterostructural synergy are developed. This configuration shows greater performance than commercial Pt/C, achieving an overpotential of 23.2 mV at 10 mA cm−2 and maintaining long‐term stability for 55 h in half‐cell tests. Furthermore, the practical AEMWE test, incorporating c‐RP/IP HNTs, demonstrated a remarkable single‐cell performance of 12.23 A cm−2 at 2.0 V and operated stably under 1.0 A cm−2 for over 250 h. This surpasses that of the state‐of‐the‐art proton‐exchange membrane WE. [ABSTRACT FROM AUTHOR]

High triplet energy exciplex hosts are developed using new electron transport type hosts with triphenylsilyl blocking groups to obtain high solid state triplet energy and exciplex triplet energy. Two triphenyltriazine derived hosts, 2‐phenyl‐4,6‐bis(4‐(triphenylsilyl)phenyl)‐1,3,5‐triazine (pSiTrz) and 2‐phenyl‐4,6‐bis(3‐(triphenylsilyl)phenyl)‐1,3,5‐triazine (mSiTrz), are synthesized as the high triplet energy hosts with electron transport properties. The two hosts show high triplet energy over 2.90 eV both in solution and solid film, and afford high triplet energy over 2.90 eV in the mixed hosts with a hole transport type 2,2′‐di(9H‐carbazol‐9‐yl)‐1,1′‐biphenyl (oCBP) host. The doping of a deep blue phosphorescent emitter in the mixed host oCBP:mSiTrz achieves high external quantum efficiency over 20% with a color coordinate of (0.14, 0.16) and device lifetime of longer than 1000 h at 100 cd m‐2. This is the first demonstration of simultaneous achievement over 20% external quantum efficiency (EQE) and 1000 h lifetime in the deep blue organic light‐emitting diodes with a x+y color coordinate value below 0.30. [ABSTRACT FROM AUTHOR]