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In this study, metallic glass is designed tunable for promising functional applications via a facile and stable, one-step process. Creative approach about alloy design and process is based on the unique properties of the Ti-Cu-Ni-Sn metallic glass that are afforded by the varying oxygen affinities of the four constituent elements. This metallic glass exhibits homogeneous nucleation of oxides and uniform formation of the various metal oxides. The alloy design and hydrothermal synthesis to customize the metallic glasses are the most critical factors that determine the characteristics of the metal oxides and the resulting nanostructures and photoelectrode properties. This enables the desired element to be selectively grown via a facile single-step process. These results provide a promising road map for the application of metallic glasses to photoelectrochemical (PEC) solar water splitting, as well as various other new possibilities.

The advancement of electrolyte systems has enabled the development of high-performance Li metal batteries (LMBs), which have tackled intractable dendritic Li growth and irreversible Li plating/stripping. In particular, the robust electrode–electrolyte interfaces created by electrolyte additives inhibit the deterioration of the cathode and the Li metal anode during repeated cycles. This paper reports the application of electrode–electrolyte interface modifiers, namely lithium nitrate (LiNO3) and lithium difluoro(bisoxalato) phosphate (LiDFBP) as a N donor and F donor, respectively. LiDFBP and LiNO3 with different electron-accepting abilities construct a mechanically robust, LiF-rich inner solid electrolyte interphase (SEI) and ion-permeable, Li3N-containing outer SEI layers on the Li metal anode, respectively. A well-structured dual-layer SEI capable of transporting Li+ ions is formed on the Li metal anode, while the cathode–electrolyte interface (CEI) on the LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode is strengthened. Ether-based electrolytes containing LiDFBP and LiNO3 lead to a long cycle life (600 cycles) of Li|NCM811 full cells at C/2 with 80.9% capacity retention and a high Coulombic efficiency (CE) of 99.94%. Structural optimization of the SEI and CEI provides an opportunity for advancing the practical uses of LMBs.

In phosphor-sensitized-fluorescent organic light-emitting diodes (PSF-OLEDs), triplet excitons generated in the emitting layer (EML) are harvested by the sensitizer and the excitonic energy is efficiently transferred to the fluorescent dopant molecules. Since a phosphorescent sensitizer is typically doped at around 10 wt.%, the sensitizer not only affects cascade energy transfer but also electrical transporting in the PSF-OLEDs. However, the electrical role of phosphorescent metal complex molecules in the EML is unclear. In this study, we report the impact of the phosphorescent sensitizer on the electrical properties of PSF-OLEDs. Through a comprehensive analysis using impedance spectroscopy in conjunction with current density (J)-voltage (V)-luminance (L) properties of the PSF-OLED, it was revealed that 10 wt.% phosphorescent sensitizer forms an electron transporting pathway inside the EML. Thus, the sensitizer molecules transform a unipolar single host into a bipolar mixed host. In other words, the phosphorescent sensitizer is an n-type host in the PSF-OLEDs. As a result, the charge balance and the operating voltage were simultaneously and significantly improved in the PSF-OLEDs.

Microscale lasers efficiently deliver coherent photons into small volumes for intracellular biosensors and all-photonic microprocessors. Such technologies have given rise to a compelling pursuit of ever-smaller and ever-more-efficient microlasers. Upconversion microlasers have great potential owing to their large anti-Stokes shifts but have lagged behind other microlasers due to their high pump power requirement for population inversion of multiphoton-excited states. Here, we demonstrate continuous-wave upconversion lasing at an ultralow lasing threshold (4.7 W cm−2) by adopting monolithic whispering-gallery-mode microspheres synthesized by laser-induced liquefaction of upconversion nanoparticles and subsequent rapid quenching (“liquid-quenching”). Liquid-quenching completely integrates upconversion nanoparticles to provide high pump-to-gain interaction with low intracavity losses for efficient lasing. Atomic-scale disorder in the liquid-quenched host matrix suppresses phonon-assisted energy back transfer to achieve efficient population inversion. Narrow laser lines were spectrally tuned by up to 3.56 nm by injection pump power and operation temperature adjustments. Our low-threshold, wavelength-tunable, and continuous-wave upconversion microlaser with a narrow linewidth represents the anti-Stokes-shift microlaser that is competitive against state-of-the-art Stokes-shift microlasers, which paves the way for high-resolution atomic spectroscopy, biomedical quantitative phase imaging, and high-speed optical communication via wavelength-division-multiplexing., Upconversion microlasers present a lot of advantages but also require high pumping powers. Here the authors present a high-performing microlaser based on anti-Stokes-shift in upconversion nanoparticles synthesized using a technique of liquid quenching.

The use of role-assigned ionic additives with different adsorption energies and distinct electron-accepting abilities enables the construction of a multilayer solid electrolyte interphase (SEI) wit...

Extremely stable white emission out of a hybrid white quantum dot-organic light-emitting diode (WQD-OLED) was achieved by developing a novel concept of device architecture. The new inverted device structure employs a thermally-evaporated red phosphorescent emitting layer (EML) with an n-type modulation and a multi-stacked hole transporting layer (HTL) on the top of solution-processed ZnO nanoparticles for an electron transporting layer and blue and green QD-mixed EML. The multi-stacked HTL, tris(4-carbazoyl-9-ylphenyl)amine (TCTA)/1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC), and the n-type modulation layer, 2,2′,2′′-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi) successfully balanced low-mobility holes with high-mobility electrons, and uniformly distributed the charges across the blue/green QD and red EMLs. In particular, the role of the n-type modulation layer was comprehensively analyzed with impedance spectroscopy and verified to minimize the undesired Auger recombination by excess charges and broaden the recombination zone. Consequently, highly stable white emission (0.32 ± 0.02, 0.31 ± 0.02) in CIExy color coordinates over 4 V operating voltage range (or two decades of current density), 3.92% external quantum efficiency, and 3.83 h device lifetime at 500 cd m−2 up to 50% of the initial luminance (LT50) were simultaneously obtained.

This study reports the effects of NiO nanoparticle (NP) size on the sensing performance of NiO NP-decorated SnO2 nanorods (NRs). NiO NP-decorated SnO2 NRs were synthesized using a two-step process: 1) thermal evaporation of tin powders in an oxidizing atmosphere based on the vapor-liquid-solid growth mechanism and 2) solvothermal decoration of SnO2 NRs with NiO NPs. X-ray diffraction and transmission electron microscopy analyses revealed that both the SnO2 NRs and the NiO NPs were polycrystalline. Scanning electron microscopy images showed that the diameters of the NRs ranged from 100 to 200 nm and that those of the small and the large NiO NPs ranged from 20 to 30 nm and from 80 to 180 nm, respectively. The small NiO NP-decorated SnO2 NRs showed stronger response to NO2 than did the large NiO NP-decorated SnO2 NRs over the concentration range of 0.5–100 ppm. Decoration of SnO2 NRs with small NiO NPs resulted in enhanced sensing performance whereas decoration of SnO2 NRs with large NiO NPs deteriorated the sensing performance. The superior NO2 gas sensing performance of the small NiO NP-decorated SnO2 NR sensor as compared to that of the large NiO NP-decorated SnO2 NR sensor was attributed to a higher ratio of n-SnO2 to p-NiO and a higher number of p-n heterojunctions for the same volume of NiO in the former than in the latter. In addition, the small NiO NP-decorated SnO2 NR sensors showed selectivity toward NO2 against other competing gases such as SO2, CO2, CO, H2, C7H8 and C6H6.

In2O3/SnO2 composite nanoparticles (NPs) were synthesized by a hydrothermal method. Fringes and spotty patterns were observed in high-resolution TEM images and corresponding selected area electron diffraction pattern, respectively, suggesting the nanoparticles were single crystals. X-ray diffraction results revealed that the In2O3/SnO2 composite NP sensor consisted of three phases: In2O3, SnO2 and In2Sn2O7−x (indium tin oxide: ITO). Energy-dispersive X-ray spectrum of the 9:1 In2O3/SnO2 composite NPs showed the atomic ratio of In2O3 to SnO2 was close to 9:1. The response of the chemiresistive sensor to CO was 9.2, which is within the highest 15% among the response values reported for the past 10 years. The ITO NP-based gas sensor is selective toward CO against other reducing gases such as toluene, acetone and benzene. The enhanced response of the 9:1 In2O3/SnO2 composite NP sensor to CO compared to the pure In2O3 NP sensor can be explained mainly by the stronger resistance modulation at the In2O3/SnO2 junctions.

Force calculation, stress, and fatigue analysis are major issues in machine design to ensure the life expectancy of sprocket-gear power transmission systems. Therefore, this study aims to conduct a theoretical analysis of bending stresses to select the size and component materials for the power transmission part of a Chinese cabbage collector that is under development. The three-dimensional models of a 14T sprocket gear for two steel materials, SCr420H and SM45C, were generated, employing commercial software. The bending stresses, deformations, and fatigue damages of the designed sprocket were determined by varying the face width and pressure angle of the sprocket teeth. The Lewis and American Gear Manufacturer Association (AGMA) equations were used to calculate the bending stresses. The calculated bending-stress values were compared with the stress values obtained from finite-element analysis (FEA). The maximum stress values on the gear teeth were 650.07, 826.23, and 840.77 MPa for a 20° pressure angle by using the Lewis, AGMA, and FEA methods, respectively. The simulated maximum stress value was higher than the yield strength of the SM45C steel and lower than the yield strength of the SCr420H steel. In addition, the maximum face width showed the minimum bending stress and fatigue damage for the selected material. Hence, considering the safety factor, the steel material SCr420H was selected with a 4.5-mm face width for designing the power transmission part of the Chinese cabbage collector. The analysis of bending stresses presented in this research can guide the design of a sprocket for the efficient transfer of Chinese cabbages using the proposed Chinese cabbage collector.

The disposal of by-products of duck production, including duck skin, is a serious concern as it results in environmental pollution. The objectives of this study were to investigate the optimal pretreatment conditions for swelling duck skin and their extraction methods as a novel source. Gelatin was extracted using water bath, sonication, superheated steam, and microwave extraction methods. The gelatin extraction yield and gelatin powder yield were the highest with the superheated steam extraction method. The melting point and gel strength of gelatin extracted using the superheated steam method were the lowest. The viscosity of gelatin extracted with the superheated steam and microwave extraction methods was higher than that of gelatin extracted with the other methods. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis patterns of gelatin extracted using the superheated steam and microwave extraction methods showed more intense bands than those of gelatin extracted using the other methods. Our results showed that gelatin extracted from duck skin using the superheated steam extraction method had optimal physical properties and therefore can be used in meat products.

Ultimate device performances of blue phosphorescent organic light-emitting diodes, an external quantum efficiency of 27.6%, a device lifetime over 10 000 h at 100 cd m−2, and pure blue color coordinates of (0.12, 0.13), were simultaneously achieved using a device architecture employing an electroplex host. A high triplet energy electron transport type host derived from a triazine core, a carbazole substituent, and a triphenylsilyl blocking unit was newly synthesized for the purpose of developing the high emission energy electroplex host. The electroplex host functioned as a carrier balancing host for high external quantum efficiency and a lifetime extending host of pure blue phosphorescent organic light-emitting diodes. This work demonstrates ultimate device performances, high external quantum efficiency and long lifetime, in pure blue phosphorescent organic light-emitting diodes. In particular, the lifetime limit of pure blue phosphorescent organic light-emitting diodes was overcome by demonstrating an over 10 000 h lifetime.

The effect of cationic chlorides has been studied to achieve high quality perovskite films, for high performance perovskite solar cells. However, the role of cationic chloride additives which form mixed-cations on the perovskite structure is still unclear. Investigating the crystal morphology and stability of perovskite films for various sizes or concentrations of cationic chlorides is an essential part of the optoelectronic perovskite study. This paper investigates how cationic chlorides GuCl, FACl, CsCl, RbCl, and KCl, with different cationic sizes and concentrations, affected FAPbI3 perovskite. By forming mixed-cations by the addition of cationic chlorides with appropriate cation size and concentration, based on the tolerance factor, the crystallinity of the perovskite film was improved, achieving a lifetime 2.50 times longer, and a grain size 2.44 times larger. As a result, the efficiency of the perovskite solar cells is increased to 23.28%, and certified as 22.65% at Newport with optimized cationic chlorides. To understand the effect of the cation size and concentration of the cationic chlorides, theoretical analysis of the mechanism by which the cationic chlorides increased the crystallinity was performed using density functional theory calculations. The results revealed the effect of the various cationic chlorides on perovskite phase structures and matched the experimental results.

Modern H2-based energy storage and conversion devices require a polymer electrolyte membrane (PEM) fuel cell–based integrated power system with synergistic heat integration. The key issue in integrated power systems is developing a PEM that can operate at 200–300 °C. However, currently used phosphoric-acid-based high-temperature PEM fuel cells limited stability at higher operating temperatures. Herein, we introduce a cerium hydrogen phosphate (CeHP) PEM that conducts protons above 200 °C through a self-assembled network (SAN). The SAN-CeHP-PBI reached maximum power densities of 2.4 W cm-2 and operate stably for over 7000 minute without any voltage decay at 250 ℃ under H2/O2 and anhydrous conditions. The developed fuel cell can be combined with an external hydrogen generator that uses a liquid hydrogen carrier such as N-ethylcarbazole and methanol as fuel, thus achieving a high energy efficiency. The thermal stability and fuel flexibility of these SAN-CeHP-PBI demonstrate potential for commercial applications.

The origin of efficiency-lifetime trade-off in triplet–triplet fusion (TTF) type blue fluorescent organic light-emitting diodes (OLEDs) was investigated and the device structure to resolve the issue was developed. The efficiency and lifetime were simultaneously improved in the blue OLEDs by developing a multilayer hole transport stack which can adjust carrier densities and recombination zone in the emitting layer (EML). It was found that electron leakage from EML and high spatial density of excitons in the vicinity of the electron blocking layer for high TTF rates by narrow recombination zone are the detrimental factors for efficiency-lifetime trade-off. A multilayer hole transport stack employing a deep highest occupied molecular orbital hole transport layer and an electron blocking layer combined with an appropriate hole blocking layer simultaneously improved the power efficiency by 16% at 500 cd/m2 and lifetime by almost 100% (from 73 h up to 145 h). In addition, the low efficiency in the low luminance region was also completely controlled, resulting in negligible efficiency variation in the entire luminance range.

Although polycarbonate (PC) materials are well known to have poor adhesion to other surfaces, few studies have been conducted on the improvement of their adhesive properties via surface chemical functionalization. Herein, we report the enhancement in the adhesion properties of PC by adapting two silane coupling agents, namely (3-glycidoxypropyl) methyldiethoxysilane (GPTMS) and (3-aminopropyl) trimethoxysilane (APTMS), on the surface. We tested the adhesion with an epoxy-based adhesive consisting of bisphenol A diglycidyl ether (BADGE) and trientine (trien). The chemical interaction between the amine groups of the hardener (trien) and the epoxy rings of an epoxy-functionalized PC (PC-GPTMS) sample surface was observed with X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. We found that the amine-functionalized PC (PC-APTMS) can also form crosslinked polymeric structures with the BADGE after curing. Compared to the bare PC, an increase in the shear strength of up to 168% and 163% was observed from the PC-GPTMS and PC-APTMS, respectively. In contrast, the ultraviolet-ozone (UVO) and O2 plasma-treated samples showed a negligible increase in adhesion strength. These results strongly suggest that the chemical functionalization of PC substrates with coupling agents significantly enhances the adhesion properties of PCs.

Summary One of the most effective methods to achieve high-performance perovskite solar cells has been to include additives that serve as dopants, crystallization agents, or passivate defect sites. Cl-based additives are among the most prevalent in literature, yet their exact role is still uncertain. In this work, we systematically study the function of methylammonium chloride (MACl) additive in formamidinium lead iodide (FAPbI3)-based perovskite. Using density functional theory, we provide a theoretical framework for understanding the interaction of MACl with a perovskite. We show that MACl successfully induces an intermediate to the pure FAPbI3 α-phase without annealing. The formation energy is related to the amount of incorporated MACl. By tuning the incorporation of MACl, the perovskite film quality can be significantly improved, exhibiting a 6× increase in grain size, a 3× increase in phase crystallinity, and a 4.3× increase in photoluminescence lifetime. The optimized solar cells achieved a certified efficiency of 23.48%.

Natural gas has been suggested as an alternative fuel for compression ignition (CI) engines because it generates significantly less pollutants and has a smaller carbon footprint, while maintaining the cycle efficiency. However, the high auto-ignition temperature of natural gas typically requires the use of a quasi-compression ignition method such as homogenous charge compression ignition (HCCI) or a dual-fuel mode. Yet, methods such as these are unable to realize the full potential of high efficiency and low emissions. This motivated us to evaluate the applicability of a high-pressure direct-injected natural gas jet for a pure CI engine under various engine load, injection timing, and injection pressure conditions using a single cylinder CI engine with a compression ratio of 15.5. The intake temperature was raised to 400 °C to achieve the auto-ignition temperature of methane after compression and a multi-hole GDI injector capable of operating at a pressure of 400 bar was used for fuel injection. As a result, CI operation was possible, but ignition occurred after the end of the injection in the form of a partially premixed flame rather than a diffusion flame for all conditions under which the engine was operated. A sufficient equivalence ratio of 0.8 was achieved at an injection pressure of 300 bar and injection duration of 1.6 ms with the multi-hole GDI injector, and the GMEP value varied from 2 bar to 5.5 bar according to the equivalence ratio. However, at an equivalence ratio of 0.7 or higher, the combustion efficiency decreased drastically because of the limit of the volume fraction of the piston bowl at TDC and the narrow nozzle distribution of the GDI injector. Measurement of the pollutants indicated that the total number of particles from methane CI operation exceeded that of diesel at an equivalence ratio of 0.74 in the same engine setup because of incomplete combustion; however, the total mass of the particulate matter (PM) was approximately 15% of the diesel because the average particle size from methane CI was approximately one third smaller than that of diesel. However, the high post-compression temperature for the auto-ignition of methane gas resulted in a high peak temperature, which resulted in the production of approximately 2000 ppm NOx under all test conditions. The results of the parametric study showed that, as the injection timing retarded, the ignition timing was almost equally retarded, thus the combustion was still observed in the form of a diffusion flame. As the injection pressure increased, the ignition delay became shorter and the emission of PM could be further reduced, but the NOx emission increased.

Practical electronic device applications using graphene-based materials dictate that their band gap must be tunable. The synthesis of hydrogenated graphene has received much attention due to the de...

A series of M-quinolate complexes were theoretically investigated to understand the effect of metal ions on electronic and charge transport properties by employing density functional theory simulation. It was found that both electronic and carrier transport properties in M-quinolate materials significantly depend on singly oxidized metal ions. In particular, Csq apparently showed an excellent advantage over other M-quinolate materials (M = Li, Na, K, Rb, Cs, Cu, Ag, and Au) in terms of electron mobility and injection. In addition, the dimerization and vertical detachment energies of all M-quinolate materials were compared to understand self-aggregation effect on carrier transport. As a result, it is expected that Csq is not only likely to be present in dimer form, but also reduce the density of electron traps in electron transporting materials.

Charge transport and electronic transition properties of a series of newly designed anthracene-based non-doped blue emitters were investigated by density functional theory calculations. For a highly efficient non-doped device, Cz3PhAn-based emitters were designed to suppress the hole and electron reorganization energies required for structural relaxation with respect to the changes of charged states. As a result, the hole hopping rates of triphenylamine (TPA) and phenylbenzimidazole (PBI) substituted Cz3PhAn derivatives (1, 4, and 5–7) were tremendously enhanced as compared to that of Cz3PhAn due to the suppression of the reorganization energy of holes, λh. Moreover, 1 and 4 emitters showed almost identical hopping rates of holes and electrons, which can possibly lead to a perfect charge balance and high efficiency. The photo-physical properties showed that the emission energy of all 1–10 emitters is in 439–473 nm range. It is expected that our rational design strategy can help develop non-doped blue fluorescent emitters for high efficiency.

The study focuses on evaluating fully coupled conjugate heat transfer (CHT) simulation in a ribbed cooling passage with a fully developed flow assumption using large eddy simulation (LES) with the immersed boundary method (IBM-LES-CHT). The IBM-LES and the IBM-CHT frameworks are validated by simulating purely convective heat transfer in the ribbed duct, and a laminar boundary layer flow over a 2D flat plate with heat conduction, respectively. For the main conjugate simulations, a ribbed duct geometry with a blockage ratio of 0.3 is simulated at a bulk Reynolds number of 10,000 with a conjugate boundary condition applied to the rib surface. The nominal Biot number is kept at 1, which is similar to the comparative experiment. It is shown that the time scale disparity between turbulent fluid flow and heat conduction in solid can be overcome by using an artificially high solid thermal diffusivity. While the diffusivity impacts the instantaneous fluctuations in temperature and heat transfer, it has an insignificant effect on the predicted Nusselt number. Comparison between IBM-LES-CHT and iso-flux heat transfer simulations shows that the iso-flux case predicts higher local Nusselt numbers at the back face of the rib. Furthermore, the local Nusselt number augmentation ratio (EF) predicted by IBM-LES-CHT is compared with experiment and another LES conjugate simulation. The present LES calculations predict higher EFs on the leading face of the rib and show a different trend at the trailing face when CHT is activated.

Solid electrolyte interphases generated using electrolyte additives are key for anode-electrolyte interactions and for enhancing the lithium-ion battery lifespan. Classical solid electrolyte interphase additives, such as vinylene carbonate and fluoroethylene carbonate, have limited potential for simultaneously achieving a long lifespan and fast chargeability in high-energy-density lithium-ion batteries (LIBs). Here we report a next-generation synthetic additive approach that allows to form a highly stable electrode-electrolyte interface architecture from fluorinated and silylated electrolyte additives; it endures the lithiation-induced volume expansion of Si-embedded anodes and provides ion channels for facile Li-ion transport while protecting the Ni-rich LiNi0.8Co0.1Mn0.1O2 cathodes. The retrosynthetically designed solid electrolyte interphase-forming additives, 5-methyl-4-((trifluoromethoxy)methyl)-1,3-dioxol-2-one and 5-methyl-4-((trimethylsilyloxy)methyl)-1,3-dioxol-2-one, provide spatial flexibility to the vinylene carbonate-derived solid electrolyte interphase via polymeric propagation with the vinyl group of vinylene carbonate. The interface architecture from the synthesized vinylene carbonate-type additive enables high-energy-density LIBs with 81.5% capacity retention after 400 cycles at 1 C and fast charging capability (1.9% capacity fading after 100 cycles at 3 C)., Interface architecture generated from electrolyte additives is a key element for high performance lithium-ion batteries. Here, the authors present that a stable and spatially deformable solid electrolyte interphase mitigates interfacial degradation of Si-embedded anodes and Ni-rich cathodes.

Upconversion nanocrystals (UCNs)‐embedded microarchitectures with luminescence color transition capability and enhanced luminescence intensity under extreme conditions are suitable for developing a robust labeling system in a high‐temperature thermal industrial process. However, most UCNs based labeling systems are limited by the loss of luminescence owing to the destruction of the crystalline phase or by a predetermined luminescence color without color transition capability. Herein, an unusual crystal phase transition of UCNs to a hexagonal apatite phase in the presence of SiO2 nanoparticles is reported with the enhancements of 130‐fold green luminescence and 52‐fold luminance as compared to that of the SiO2‐free counterpart. By rationally combining this strategy with an additive color mixing method using a mask‐less flow lithography technique, single to multiple luminescence color transition, scalable labeling systems with hidden letters‐, and multi‐luminescence colored microparticles are demonstrated for a UCNs luminescence color change‐based high temperature labeling system., The multiple luminescence color tuning of upconversion nanocrystals (UCNs) with enhanced intensity is realized via a SiO2‐NPs involved unique crystal phase transition method. As a proof of concept demonstration, the robust optical labeling system through stepwise alteration of the luminescence color or hidden pattern generation in UCNs embedded microarchitectures are suggested.

Polymeric materials have been used to realize optical systems that, through periodic variations of their structural or optical properties, interact with light-generating holographic signals. Complex holographic systems can also be dynamically controlled through exposure to external stimuli, yet they usually contain only a single type of holographic mode. Here, we report a conjugated organogel that reversibly displays three modes of holograms in a single architecture. Using dithering mask lithography, we realized two-dimensional patterns with varying cross-linking densities on a conjugated polydiacetylene. In protic solvents, the organogel contracts anisotropically to develop optical and structural heterogeneities along the third dimension, displaying holograms in the form of three-dimensional full parallax signals, both in fluorescence and bright-field microscopy imaging. In aprotic solvents, these heterogeneities diminish as organogels expand, recovering the two-dimensional periodicity to display a third hologram mode based on iridescent structural colours. Our study presents a next-generation hologram manufacturing method for multilevel encryption technologies.

We present evaluation results of the 940nm 400mW transverse single-mode laser diodes (LDs) with real reflective index self-aligned (RISA) structure based on graded index separate confinement hetero structures (GRIN-SCH) for a three-dimensional (3D) depth sensor. The AlGaAs/InGaAs laser diodes that are adopted with RISA structure have many advantages over conventional complex refractive index guided lasers, what include low operating current, high temperature operation and stable fundamental transverse-mode operation up to high power levels. Simultaneously, the RISA process is easy to control the waveguide channel width and does not require stable oxide mask for the regrowth of aluminum alloys, so it is possible to manufacture high output power and high reliability laser diodes. At the optical power 400mW under the continuous-wave (CW) operation, Gaussian narrow far-field patterns (FFP) are measured with the full-width at half-maximum vertical divergence angle of 23°. A threshold current (Ith) of 33mA, slope efficiency (SE) of 0.81mW/mA and operating current (Iop) of 503mA are obtained at room temperature. Also, we could achieve catastrophic optical damage (COD) of 657mW and long-term reliability of 60°C with TO-56 package.

Lifetime study of blue phosphorescent and thermally activated delayed fluorescent organic light-emitting diodes was carried out to understand the dominant degradation process during electrical operation of the devices. Doping concentration dependence of the phosphorescent and thermally activated delayed fluorescent organic light-emitting diodes was studied, which demonstrated long lifetime at low doping concentration in the phosphorescent devices and at high doping concentration in the thermally activated delayed fluorescent devices. Detailed mechanism study of the two devices described that triplet–triplet annihilation is the main degradation process of phosphorescent organic light-emitting diodes, whereas triplet–polaron annihilation is the key degradation factor of the thermally activated delayed fluorescent devices.

By utilizing a novel design of an electronic device with microfabricated through-etched slits for transmission electron microscopy (TEM), single-walled carbon nanotubes (SWNTs) suspended over two metal electrodes were successfully characterized. A semiconducting-semiconducting intramolecular junction (IMJ) was found from a change in chirality along the tube. Interestingly non-linear current-voltage characteristic was found despite almost negligible difference in the band-gap energy (13 meV). The non-linear electrical transport property can be caused by asymmetric defect states positioned in the band-gap of two semiconducting tubes, which make one as donor (similar to a p-type semiconductor) and the other as acceptor (similar to n-type semiconductor). The strain by deformation along the tube can also cause the electrical non-linearity.

Summary Organometallic perovskite devices have been intensively studied in recent years; however, a comprehensive understanding of their many unique material properties remains to be unveiled. In this work, we demonstrate for the first time a simple, reversible, and non-destructive post-treatment method of anion exchange between CsPbX3 perovskite nanocrystals (CsPbCl3 ⇌ CsPbBr3 ⇌ CsPbI3) with halogenated solvents, which is mediated by nucleophilic phosphine ligands. Anion exchange between CsPbX3 perovskite nanocrystals and haloalkane solvents (CHCl3, CHBr3, CH3CH2I) proceeded readily upon addition of nucleophilic trialkyl phosphines and could be controlled via nucleophile concentration and reaction time, allowing precise tuning of the anion composition and band gap. With our simple method, we obtained luminescence covering the entire visible spectrum from 400 to 700 nm. Furthermore, saturated and vivid RGB LED devices were successfully fabricated using the anion-exchanged nanocrystals.

Comprehensive study to understand the degradation mechanism of high efficiency blue organic light-emitting diodes by charge transport layers was carried out by managing the device parameters and charge transport materials. Although it has been generally accepted that the charge transport layers are important for long lifetime, the degradation mechanism was not clear. From this work, it was revealed that exciton quenching of emitters by the degradation products of charge transport layers is the main degradation pathway of blue phosphorescent and thermally activated delayed fluorescent organic light-emitting diodes. It was described that the degradation of the blue devices by the charge transport layers would be largely avoided by separating the exciton generating emitters from the charge transport layers by shifting the exciton formation zone to the center of the emitting layer. Eventually, the lifetime of the blue devices with the emission zone fall apart from the charge transport layers was not affected by the charge transport layers because exciton quenching by the degradation products of the charge transport layers was suppressed.

As a new class of sensitizers, poly(3,4-ethylenedioxythiophene) (PEDOT) and poly(hydroxymethyl-3,4-ethylenedioxythiophene) (PEDOT-OH) quantum dots (QDs) are successfully introduced for solid-state QD-sensitized solar cells utilizing polymer electrolyte with I–/I3– redox couple for the first time. These two polymer QDs were prepared by facile top-down nanoprecipitation method from dodecyl sulfate-doped PEDOT and PEDOT-OH nanofibers. In particular, PEDOT-OH QDs containing -OH anchoring groups have a wider range of light absorption, and tighter adsorption onto the TiO2 surface, compared to PEDOT QDs, yielding higher photocurrent density and consequently higher energy conversion efficiency beyond 1% under 1 sun conditions, which is higher than that of most carbon nanodot sensitizers ever reported. Interestingly the range of the light absorption is further broadened by spontaneous re-doping the polymer QDs by I2 and/or I3– dissolved in the polymer electrolyte. Moreover, QDSCs utilizing both polymer QDs show ex...

The electrical conductivity and catalytic activity of nanofibrous poly(3,4-ethylenedioxythiophene)s (PEDOT NFs) was improved by redoping with dimethyl imidazolium iodide (DMII) as a charge transfer facilitator. Addition of the new DMII dopant into the PEDOT NFs reduced the concentration of dodecyl sulfate anions (DS–) predoped during the polymerization process and concomitantly enhanced the doping concentration of I– by ion exchange. Redoping with DMII increased the mobility of the PEDOT NFs by up to 18-fold and improved the conductivity due to the enhanced linearization, suppressed aggregation, and improved crystallinity of the PEDOT chains. The catalytic activity was also improved, primarily due to the increase in the compatibility and the effective surface area upon replacement of sticky DS– with the more basic and smaller I– of DMII on the surface of the PEDOT NFs. The charge-transfer resistance across the interface between the poly(ethylene oxide)-based solid polymer electrolyte and PEDOT NF counter ...

High-capacity Si-embedded anodes and Li-rich cathodes are considered key compartments for post lithium-ion batteries with high energy densities. However, the significant volume changes of Si and the irreversible phase transformation of Li-rich cathodes prevent their practical application. Here we report lithium fluoromalonato(difluoro)borate (LiFMDFB) as an unusual dual-function additive to resolve these structural instability issues of the electrodes. This molecularly engineered borate additive protects the Li-rich cathode by generating a stable cathode electrolyte interphase (CEI) while simultaneously tuning the fluoroethylene carbonate (FEC)-oriented solid electrolyte interphase (SEI) on the Si–graphite composite (SGC) anode. The complementary electrolyte design utilizing both LiFMDFB and FEC exhibited an improved capacity retention of 85%, a high Coulombic efficiency of ∼99.5%, and an excellent energy density of ∼400 W h kg−1 in Li-rich/SGC full cells at a practical mass loading after 100 cycles. This dual-function additive approach offers a way to develop electrolyte additives to build a more favorable SEI for high-capacity electrodes.

An extremely long lifetime blue organic light-emitting diode (OLED) was developed through managing the electron density and an S-shaped variation of efficiency in blue fluorescent organic light-emitting diodes (FOLEDs) using carrier blocking layers and systematically analyzed in conjunction with the efficiency–lifetime interrelationship. Firstly, with a sensing layer, the majority carriers in the emitting layer were identified as a function of applied voltage and found to be electrons in our FOLEDs. In our reference device, both hole and electron leakage currents are present. To analyze the influence of leakage current on the efficiency variation and lifetime in our devices, two different classes of hole blocking layers were inserted between the emitting layer and the electron transport layer. By managing electron injection into the emitting layer, we successfully and simultaneously controlled the S-shape feature in efficiency and improved the operational stability, which resulted in a state of the art blue lifetime of 300 h at 500 cd m−2 up to 97% of the initial luminance. The lifetime of the blue FOLEDs was extended by more than 5 times by introducing an electron-leakage suppressing carrier blocking material at the interface between charge transport layers and emitting layers.

In general, electron transport layer (ETL) in organic light-emtting diodes (OLEDs) consists of single component of electron transporting material (ETM) or a mixture with n-dopant such as 8-hydroxyquinolinolato-lithium (Liq). However, there exists a limit to controlling a wide range of carrier density in OLEDs according to the required characteristics of the devices due to electrically insulating property of Liq. Here, we suggest a universal strategy to construct an efficient ETL. We synthesized two ETMs, diphenyl-[4-(10-phenyl-anthracene-9-yl)-phenyl]-amine (An-Ph) and phneyl-[4-(10-phenyl-anthracene-9-yl)-phenyl]-pyridin-3-yl-amine (An-Py) that have the same core structures with different polarities in functional groups. The electrical characteristics of electron-only-devices (EODs) were investigated by space charge limited current (SCLC) modeling and impedance spectroscopy analysis. Interestingly, the homostructure type ETL composed of An-Ph and An-Py showed not only superior electron transporting capability, but also the possibility of controlling electron injection and transporting in a wide range compared to the heterostructure type ETL of An-Ph and Liq. Compared to the An-Ph-only EOD, the electron mobility in 75% An-Py-mixed homostructure EOD increased by almost 4 orders of magnitude. Such dramatic variation of electron mobility was achieved thanks to the molecular design strategy to separate charge injection and charge transport regions within a molecule, which consequently induced the giant surface potential (GSP) effect between the ETL/cathode interface. As a result, the external quantum efficiency (EQE) of blue fluorescent and phosphorescent OLEDs with the homostructure ETLs was enhanced by 28.6% and 34%, respectively, compared to that of each control device without manipulating outcoupling effects.

In this study, a Cohesive Zone Model (CZM) was used to predict the progressive failure behavior of adhesive joining of a domeseparated composite pressure vessel according to variation in the temperatures. A set of cohesive zone parameters for the adhesive material were obtained through Mode I, Mode II, and Mixed Mode I/II interfacial fracture toughness tests. In order to evaluate the effect of temperature on the interfacial fracture toughness, in situ temperature environments were simulated in the range -30 to 60oC, using an environmental chamber and furnace. The double-lap joint test was suggested as a way to verify the proposed CZM and simulation procedure. It was found that good accuracy in the prediction of debonding loads, and the damage onset and growth of adhesive joining, was obtained between the numerical predictions and the experimental results. The results of progressive failure analysis of the adhesive joining of the dome-separated composite pressure vessel showed that the maximum debonded length was predicted to be about 6.0% of the total adhesive length and that the damage onset and propagation behavior of the adhesive joining showed a similar tendency under room and low-temperature environments. However, in the high-temperature environment (60oC), the debonding of the adhesive joining tended to propagate early and quickly compared to the same action under room and low-temperature conditions.

A highly luminescent CsPbBr3-perovskite structure was synthesized by dropping a PbBr2-DMF solution to bulk CsBr. The bulk CsBr was used as the matrix for the CsPbBr3. The product showed a strong green emission with a narrow full width at half maximum (FWHM). This method is very fast, and it is suitable for mass production and large-area coating. The particle sizes are more than hundreds of nanometers, and orthorhombic crystal structures are also evident. Interestingly, the case here shows a strong photoluminescence (PL) emission at room temperature (RT). A new hypothesis between the particle size of CsPbBr3 and the quantum yield (QY) is therefore suggested by the authors. The free charge carriers in the bigger particles have enough space for free migration, and as a result, the probability of recombination is decreased and a low QY is observed. The migration of the free charge carriers in small particles is inhibited by a spatial limit. The CsPbBr3 particles can be directly synthesized on diverse substrates including glass, fabric, and paper. The finding of this study can provide a novel way to achieve applications and scalable processes; especially, owing to the substrate diversity, it can be applied to continuous processes such as R2R for mass production.

We report the effects of a combination of Pd-decoration and Bi 2 O 3 -ZnO core-shell formation on the response of the Bi 2 O 3 nanorod gas sensor to benzene. Pd-decorated Bi 2 O 3 –ZnO core–shell nanorods were synthesized by a four-step process including thermal evaporation of Bi powders in an oxygen atmosphere, atomic layer deposition of ZnO, and Pd decoration, followed by high-temperature annealing. The formation of Pd-decorated Bi 2 O 3 –ZnO core–shell nanorods was confirmed by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and energy-dispersive spectrometric elemental mapping. The Pd-decorated Bi 2 O 3 –ZnO core–shell nanorod sensor showed far stronger response to benzene improved compared to those of the Bi 2 O 3 –ZnO core–shell nanorod and Pd-decorated ZnO nanorod sensors. The Pd-decorated Bi 2 O 3 –ZnO core–shell nanorod sensor exhibited a response ( R a /R g ) of 28.0 to 200 ppm of benzene at 300 °C, whereas those of the Bi 2 O 3 –ZnO core–shell nanorod, and Pd-decorated ZnO nanorod sensors were 9.1 and 8.3, respectively. The extraordinarily strong response of the Pd-decorated Bi 2 O 3 –ZnO core–shell nanorod sensor compared to other sensors might be attributed to the intensified potential barrier modulation at the Bi 2 O 3 –ZnO interface due to the Pd-induced enhanced generation of electrons. The Pd-decorated Bi 2 O 3 –ZnO core–shell nanorod sensor also showed very good selectivity toward benzene against other reducing gases, such as ethanol, toluene, carbon monoxide, and acetone.

Poly(3,4-ethylene dioxythiophene)/ammonium vanadate nanofiber (E-AVNF) composites, with a diameter of 20–30 nm and length of 2–5 μm were synthesized by a simple refluxing method using ammonium persulfate ((NH 4 ) 2 S 2 O 8 ) and vanadium pentoxide (V 2 O 5 ), accompanied intercalation of ammonium cation during reflux process. 3,4-ethylene dioxythiophene (EDOT) was co-intercalated into ammonium vanadate nanofiber layers and simultaneously its polymerization occurred. This intercalation mechanism of E-AVNF was confirmed by X-ray diffractometer (XRD), infrared spectroscopy (IR), thermogravimetric analysis (TGA) scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The photovoltaic and catalytic performances were characterized by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). As a result, new nanocomposite electrodes were fabricated without relying on autoclave, high temperature/pressure, surfactants, catalysts or harmful solvents. Moreover, well-defined E-AVNF composite shows a power conversion efficiency of 6.0% as a counter electrode (CE) in the dye-sensitized solar cells (DSCs).

Functionally Graded Materials (FGMs) have been used as advanced structures in high temperature regions for excellent thermal barriers. In this regard, present study considers the compensation of the shear stress effects in thermal environments to be more crucial than conventional evaluation. As the beam model with thermo-mechanical behavior, the material properties are considered temperature-dependent and vary continuously in the thickness direction. For the structure, First-order Shear Deformation Theory (FSDT) is employed in the formulation. And the model is based on the neutral surface concept to consider the un-symmetric properties of materials in the thickness direction. To check the validity of present works, results are compared with previous data. Furthermore, numerical analyses are performed with the temperature-dependent shear correction factors. Also, three types of model such as the Power-law (P-), Exponential (E-) and Sigmoid (S-) FGMs are discussed in detail.

Degradation of Ir based blue phosphorescent emitters was analyzed from the viewpoint of triplet-polaron annihilation (TPA) of the emitters. Two different classes of Ir emitters, F substituted phenylpyridine type Ir emitter and F substituted phenylimidazole type Ir emitter, were compared as the blue emitters. Aging test of singlet carrier devices of the Ir emitters under polaron, exciton, and exciton-polaron revealed that the phenylimidazole type Ir emitter was relatively more resistant to the TPA degradation than the phenylpyridine type Ir emitter and extended the lifetime of blue phosphorescent organic light-emitting diodes. In addition, the lifetime and degradation of the short-living blue phosphorescent devices were improved by the host material suppressing the TPA under negative polaron using an electron scattering emitting layer structure.