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An inorganic p-type CuInS2 semiconductor was combined with the semiconducting polymer of PNDI3OT-Se1 and PNDI3OT-Se2 with different HOMO/LUMO levels for photoelectrochemical hydrogen production. Charge transfer behaviors at polymer/CuInS2 junctions were investigated by electrochemical impedance spectroscopy. The heterojunction of p-CuInS2 and n-type polymer (both PNDI3OT-Se1 and Se2) successfully made p-n junctions and showed improved charge transfer. However, we found that higher HOMO levels of polymer than valence band maximum (VBM) of CuInS2 spurred charge recombination at interfaces. As a result, CuInS2 /PNDI3OT-Se1/TiO2 /Pt, which has suitable energy levels matched between PNDI3OT-Se1 and CuInS2 , shows photocurrent (-15.67 mA cm-2 ) improved concretely when compared to a CuInS2 /TiO2 /Pt photoelectrode (-7.11 mA cm-2 ) at 0.0 V vs. RHE applied potential. Additionally, the photoelectrochemical stability of CuInS2 /PNDI3OT-Se1/TiO2 /Pt photoelectrode was also investigated.

Male infertility is a multifactorial condition. Unexplained male infertility is often caused by spermatogenesis dysfunction. Knockout of Pin1, an important regulator of cell proliferation and differentiation, produces male infertility phenotypes such as testicular immaturity and azoospermia with spermatogonia depletion and blood-testis barrier (BTB) dysfunction. Gene therapy has been clinically considered for the treatment of male infertility, but it is not preferred because of the risks of adverse effects in germ cells. Direct intracellular protein delivery using nanoparticles is considered an effective alternative to gene therapy; however, in vivo testicular protein delivery remains a pressing challenge. Here, we investigated the direct intracellular protein delivery strategy using a fibroin nanoparticle-encapsulated cationic lipid complex (Fibroplex) to restore intratesticular PIN1. Local intratesticular delivery of PIN1 via Fibroplex in Pin1 knockout testes produced fertile mice, achieving recovery from the infertile phenotypes. Mechanistically, PIN1-loaded Fibroplex was successfully delivered into testicular cells, including spermatogonial cells and Sertoli cells, and the sustained release of PIN1 restored the gene expression required for the proliferation of spermatogonial cells and BTB integrity in Pin1 knockout testes. Collectively, testicular PIN1 protein delivery using Fibroplex might be an effective strategy for treating male infertility.

RUNX2 is a master transcription factor of osteoblast differentiation. RUNX2 expression in the bone and osteogenic front of a suture is crucial for cranial suture closure and membranous bone morphogenesis. In this manner, the regulation of RUNX2 is precisely controlled by multiple posttranslational modifications (PTMs) mediated by the stepwise recruitment of multiple enzymes. Genetic defects in RUNX2 itself or in its PTM regulatory pathways result in craniofacial malformations. Haploinsufficiency in RUNX2 causes cleidocranial dysplasia (CCD), which is characterized by open fontanelle and hypoplastic clavicles. In contrast, gain-of-function mutations in FGFRs, which are known upstream stimulating signals of RUNX2 activity, cause craniosynostosis (CS) characterized by premature suture obliteration. The identification of these PTM cascades could suggest suitable drug targets for RUNX2 regulation. In this review, we will focus on the mechanism of RUNX2 regulation mediated by PTMs, such as phosphorylation, prolyl isomerization, acetylation, and ubiquitination, and we will summarize the therapeutics associated with each PTM enzyme for the treatment of congenital cranial suture anomalies., Regenerative medicine: Manipulating modifications that control bone-building Therapies that modulate the activity of the regulatory protein RUNX2 could potentially restore normal bone development in a range of skeletal disorders, and repair damage from injury or degeneration. RUNX2 is an essential regulator of genes that drive formation of bone-producing osteoblast cells. It can be activated or inactivated by the enzymatic addition of various chemical groups. Hyun-Mo Ryoo and colleagues at Seoul National University, South Korea, review the role of such modifications in bone disorders. For example, the loss of modifications activated by RUNX2 can result in delayed integration of the bones that form the skull. The authors highlight potential opportunities to manipulate these modification processes to treat this and other developmental disorders. Similar strategies could also promote repair of fractures or counter osteoporotic bone loss.

We report on high-performance polymeric field-effect transistors (PFETs) operating at low voltages (Vop) using a self-assembled monolayer (SAM)-passivated HfOx dielectric layer. A diketopyrrolopyrrole and quaterthiophene-based copolymer (PDPP2DT-T2) was spin-coated in air as an active channel material on top of a HfOx gate dielectric that was passivated with n-octyltrichlorosilane (OTS), n-octadecyltrichlorosilane (ODTS), and n-dodecylphosphonic acid (PAC12) SAMs. The high capacitance and low leakage current of the SAM-passivated HfOx dielectrics enabled the devices to operate at |Vop| of less than 4 V. In particular, the PFETs using ODTS-passivated HfOx demonstrated a high hole mobility (μeffh) of 1.98 cm2 V−1 s−1, a current on/off ratio of 1.4 × 104, and a threshold voltage of −0.8 V despite the fact that the device fabrication and all measurements were conducted under ambient conditions without encapsulation. Moreover, the μeffh value observed in this study is the best for high-k-dielectric-based low-voltage PFETs reported to date. This work demonstrates that our facile modification of high-k dielectrics with SAMs is a highly effective method for realizing high-performance semiconducting copolymer-based transistors working at a low Vop regime with low power consumption.

On-chip micro-supercapacitors are promising miniaturized micro-power sources for wireless sensors, portable electronic devices, and implantable medical devices due to their advanced features such as high power densities, fast charge-discharge, and superior cycling lifetimes. Transition metal silicide nanowires can meet the desired requirements for electrode materials for on-chip micro-supercapacitors, as they provide advantages such as high conductivity, high surface area, effective electrolyte transport, and ease of fabrication and integration on silicon. In the present work, we introduce freestanding single-crystalline Co2Si nanowires directly synthesized on a Si substrate for application in a high-performance on-chip micro-supercapacitor. Compared with the previously reported supercapacitors comprising Si-based nanowires, the single-crystalline Co2Si nanowires-based supercapacitor exhibits good supercapacitor performance, namely, high areal capacitance (∼983 μF cm−2 at 2 μA cm−2), high energy density (∼629 μJ cm−2 at 2 μA cm−2), and excellent cyclability (∼94% after 4000 cycles) in an ionic liquid electrolyte. To the best of our knowledge, this is the first report on the electrochemical performance of metal silicide nanowires directly grown on a Si substrate for supercapacitor application. Our results demonstrate the potential of metal silicide nanowires as electrode materials for on-chip micro-supercapacitor application.

Atomic layer deposition (ALD) is an effective coating technique for angstrom- to nanometer-scale film deposition; its advantages include uniform and conformal coverage, controlled thickness, high reproducibility, and facile synthesis of various functional materials. In this study, we analyzed sol–gel-processed ZnO films coupled with interface-engineered ALD ZnS as electron buffer layers (EBLs) for inverted polymer solar cells (IPSCs). The thickness of the ZnO film was optimized to 10 nm by adjusting the solution concentration. Subsequently, we investigated the effect of the thickness of the ALD ZnS (formed on top of the ZnO film using diethyl zinc and H2S gas) on the photovoltaic properties of the IPSCs. The IPSC device fabricated with 1.8 nm-thick ALD ZnS on ZnO EBL (ZnS C) exhibited a power conversion efficiency (PCE) of 3.17%, which represents a 22% increase over that of equivalent reference cell devices containing only a pristine ZnO EBL. Characterization of the ZnO and ALD ZnS on the ZnO films revealed that the ALD ZnS films reduced the electron resistivity and surface defects of the ZnO films; this in turn reduced the interfacial carrier recombination in the IPSCs. Overall, we demonstrated that the interface engineering of ALD ZnS favorably influenced the electrical properties of the ZnO films.

We developed a patternable synthesis method of wafer-scale NbS2, which can be applied for the fabrication of source and drain electrodes of p- and n-type organic field-effect transistors (OFETs) and logic gates. NbS2 film with high uniformity was synthesized directly on a 2-in Si wafer. NbS2 patterns of various sizes and shapes were readily synthesized onto an entire wafer. OFETs with NbS2 electrodes exhibited superior performances to those with conventional metal electrodes. The superior performance of the former OFETs was primarily a result of the enhanced crystallinity of the organic semiconductor layer deposited onto the NbS2 electrode surface. Furthermore, organic complementary circuits such as NOT, NAND, and NOR gates were successfully assembled using the resulting OFETs as a proof of applicability of these devices to complex logic circuits.

Midface hypoplasia is a major manifestation of Apert syndrome. However, the tissue component responsible for midface hypoplasia has not been elucidated. We studied mice with a chondrocyte-specific Fgfr2S252W mutation (Col2a1-cre; Fgfr2S252W/+) to investigate the effect of cartilaginous components in midface hypoplasia of Apert syndrome. In Col2a1-cre; Fgfr2S252W/+ mice, skull shape was normal at birth, but hypoplastic phenotypes became evident with age. General dimensional changes of mutant mice were comparable with those of mice with mutations in EIIa-cre; Fgfr2S252W/+, a classic model of Apert syndrome in mice. Col2a1-cre; Fgfr2S252W/+ mice showed some unique facial phenotypes, such as elevated nasion, abnormal fusion of the suture between the premaxilla and the vomer, and decreased perpendicular plate of the ethmoid bone volume, which are related to the development of the nasal septal cartilage. Morphological and histological examination revealed that the presence of increased septal chondrocyte hypertrophy and abnormal thickening of nasal septum is causally related to midface deformities in nasal septum-associated structures. Our results suggest that careful examination and surgical correction of the nasal septal cartilage may improve the prognosis in the surgical treatment of midface hypoplasia and respiratory problems in patients with Apert syndrome.

The molecular orientation of organic semiconductors (OSCs) is of fundamental importance to anisotropic electrical behavior as well as superior properties in practical applications. Here, a simple and effective method is demonstrated to fabricate highly oriented semiconducting polymers, poly(3-hexylthiophene) (P3HT) and poly{[N,N'-bis(2-octyldodecyl)-1,4,5,8-naphthalenediimide-2,6-diyl]-alt-5,5'-(2,2'-bithiophene)} (P(NDI2OD-T2)), by mass transfer effect under microchannel molds by diffusion and convection. Furthermore, parallel or perpendicular molecular arrangements relative to the channel direction were achieved by varying the widths of the microchannels, which are directly observed using polarized optical microscopy and two-dimensional grazing-incidence X-ray diffraction experiments. The method could enable the fabrication of organic field-effect transistors that exhibit anisotropic electrical properties indicating inter- or intrachain charge transport. The resulting platform will provide a simple approach for multidirectional orientations of anisotropic OSCs.

Establishing multi-colour patterning technology for colloidal quantum dots is critical for realising high-resolution displays based on the material. Here, we report a solution-based processing method to form patterns of quantum dots using a light-driven ligand crosslinker, ethane-1,2-diyl bis(4-azido-2,3,5,6-tetrafluorobenzoate). The crosslinker with two azide end groups can interlock the ligands of neighbouring quantum dots upon exposure to UV, yielding chemically robust quantum dot films. Exploiting the light-driven crosslinking process, different colour CdSe-based core-shell quantum dots can be photo-patterned; quantum dot patterns of red, green and blue primary colours with a sub-pixel size of 4 μm × 16 μm, corresponding to a resolution of >1400 pixels per inch, are demonstrated. The process is non-destructive, such that photoluminescence and electroluminescence characteristics of quantum dot films are preserved after crosslinking. We demonstrate that red crosslinked quantum dot light-emitting diodes exhibiting an external quantum efficiency as high as 14.6% can be obtained., Designing high-resolution displays based on colloidal quantum dots remains a challenge. Here, the authors demonstrate a photo-patterning method to develop CdSe-based core-shell quantum dots patterns of red, green and blue colours with diameters ranging from 7 to 20 nm and resolution of 1400 pixels per inch.

A suitable insulating polymer material that is compatible with the fabrication process of organic transistors and has excellent electrical properties is critically required for the next-generation flexible organic electronics. In this study, using a one-step polymerization method, we synthesized two different solution-processable polyimides (PIs) incorporated with abundant trifluoromethyl groups. Not only were the two resulting PIs-termed 6FDA-6FDAM-PI and 6FDA-TFMB-PI-well soluble in organic solvents, but also they showed transparent and colorless optical properties. The fluorinated PI films showed smooth surface topographies and surface energy values that were appropriate for their use in bottom-gate organic transistors. Organic transistors separately fabricated with 6FDA-6FDAM-PI and 6FDA-TFMB-PI as the gate insulators showed excellent device performance and electrical stability under various testing conditions, especially for pentacene-based devices. The excellent performance of the devices with fluorinated PIs was attributed to the enhanced microstructure of the organic semiconductor and the fluorine-rich characteristic of the underlying gate insulator. Furthermore, organic complementary circuits including the basic logic gates of NOT, NOR, and NAND were demonstrated using these devices.

The hard X-ray free-electron laser at the Pohang Accelerator Laboratory (PAL-XFEL) in the Republic of Korea achieved saturation of a 0.144 nm free-electron laser beam on 27 November 2016, making it the third hard X-ray free-electron laser in the world, following the demonstrations of the Linac Coherent Light Source (LCLS) and the SPring-8 Angstrom Compact Free Electron Laser (SACLA). The use of electron-beam-based alignment incorporating undulator radiation spectrum analysis has allowed reliable operation of PAL-XFEL with unprecedented temporal stability and dispersion-free orbits. In particular, a timing jitter of just 20 fs for the free-electron laser photon beam is consistently achieved due to the use of a state-of-the-art design of the electron linear accelerator and electron-beam-based alignment. The low timing jitter of the electron beam makes it possible to observe Bi(111) phonon dynamics without the need for timing-jitter correction, indicating that PAL-XFEL will be an extremely useful tool for hard X-ray time-resolved experiments. The Pohang Accelerator Laboratory X-ray Free Electron Laser (PAL-XFEL) in South Korea has now entered operation with a timing jitter of just 20 fs.

In this manuscript, the fabrication of polymer nonvolatile memory cells based on one-transistor–one-transistor (1T1T) device geometries is reported. A spin-coated diketopyrrolopyrrole (DPP)-based polymer semiconductor was used as the active channel layer for both the control transistor (CT) and memory transistor (MT); thermally deposited gold nanoparticles (Au NPs) were inserted between the tunneling and blocking gate dielectrics as a charge-trapping layer of the MT. In the 1T1T memory cell, the source electrode of the CT was connected to the gate electrode of the MT, while the drain electrode of the MT was connected to the gate electrode of the CT. The reading and writing processes of the memory cells operated separately, which yielded a nondestructive read-out capability. The fabricated 1T1T polymer memory cells exhibited excellent device performances with a large memory window of 16.1 V, a high programming–erasing current ratio >103, a long retention of 103 s, a cyclic stability of 500 cycles, and a 2-...

For patients with medically intractable temporal lobe epilepsy (TLE), anterior temporal resection has been mostly frequent treatment...

Post-operative pain management in spinal surgery is often a challenge. This is further complicated by the large proportion of patients with chronic pain and the significant number of patients using opioid analgesics preoperatively..

We synthesized a planar pDPPTTi-OD polymer based on diketopyrrolopyrrole (DPP) and thieno [2,3- b ]thiophene (TTi) and investigated the electrical properties of the pDPPTTi-OD polymer. pDPPTTi-OD films displayed a low optical bandgap of 1.57 eV, and HOMO and LUMO levels of −5.40 and −3.74 eV, respectively. The 150°C-annealed pDPPTTi-OD films showed a high hole mobility of 0.16 cm 2 V −1 s −1 in organic thin-film transistor (OTFT) devices. The photovoltaic properties of polymer solar cells (PSCs) incorporating the pDPPTTi-OD were also measured. A pDPPTTi-OD:PC 71 BM blend film was spin-coated at 25, 70 and 90 °C. High-temperature processing significantly improved the power conversion efficiency of PSCs by effectively reducing the PC 71 BM domain sizes, which improved the miscibility between pDPPTTi-OD and PC 71 BM. This work demonstrated that the TTi moiety is a useful donor building block for high- performance D–A type polymers in OTFTs and PSCs, and that processing temperatures should be controlled to fully realize the materials' beneficial intrinsic properties.

The Pohang Accelerator Laboratory’s X-ray free electron laser (PAL-XFEL) is a research facility currently under construction. It will provide ultra-bright (1 × 1012 photons/pulse at 12.4 keV) and ultra-short (10 − 60 femtosecond) X-ray pulses. The CXI (coherent X-ray imaging) hard X-ray experimental station is designed to deliver brilliant hard X-rays (2 − 20.4 keV) and to measure diffraction signals with a forward scattering geometry. It will not only offer imaging studies of biological, chemical and physical samples with the “diffraction-before-destruction” scheme, but also be helpful in high-field hard X-ray physics and material science. The scientific programs are currently aimed at serial femtosecond crystallography (SFX) and coherent diffraction imaging (CDI) for bio specimens, nano materials, etc. In this paper, we describe the beamline layout, beam diagnostics, X-ray focusing optics, sample environments and detector system at the CXI experimental hutch.

We observed the collision of single Pt nanoparticles (NPs) onto an Au nanowire (NW) electrode by using electrocatalytic amplification. Previously, such observations had typically been performed by using a microscale disk-type ultramicroelectrode (UME). The use of a NW electrode decreased the background noise current and provided a shielding effect, owing to adsorption of the NPs onto the insulating sheath. Therefore, the transient current signal that was caused by the collision of single NPs could be more clearly distinguished from the background current by using a NW electrode instead of a UME. Furthermore, the use of a NW electrode increased the collisional frequency and the magnitude of the transient current signal. The experimental data were analyzed by using a theoretical model and a random walk simulation model.

The performances of organic thin film transistors (OTFTs) produced by polymer solution casting are tightly correlated with the morphology and chain-ordering of semiconducting polymer layers, which depends on the processing conditions applied. The slow evaporation of a high boiling point (bp) solvent permits sufficient time for the assembly of polymer chains during the process, resulting in improving the film crystallinity and inducing favorable polymer chain orientations for charge transport. The use of high bp solvents, however, often results in dewetting of thin films formed on hydrophobic surfaces, such as the commonly used octadecyltrichlorosilane (ODTS)-treated SiO2 gate dielectric. Dewetting hampers the formation of uniform and highly crystalline semiconducting active channel layers. In this manuscript, we demonstrated the formation of highly crystalline dithienothienyl diketopyrrolopyrrole (TT-DPP)-based polymer films using a flow-coating method to enable the fabrication of ambipolar transistors an...

The Pohang Accelerator Laboratory X-ray Free Electron Laser project, a new worldwide-user facility to deliver ultrashort, laser-like x-ray photon pulses, will begin user operation in 2017 after one year of commissioning. Initially, it will provide two beamlines for hard and soft x-rays, respectively, and two experimental end-stations for the hard x-ray beamline will be constructed by the end of 2015. This article introduces one of the two hard x-ray end-stations, which is for hard x-ray pump-probe experiments, and primarily outlines the overall design of this end-station and its critical components. The content of this article will provide useful guidelines for the planning of experiments conducted at the new facility.

Thermoelectric (TE) waste heat recovery from automotive exhaust streams is a potential technology that can significantly increase the overall efficiency of vehicles and subsequently reduce the consumption of fossil fuels. By reducing the consumption of fossil fuels, vehicular application of TE generators may also potentially reduce the emission of greenhouse gases (GHGs) and other air pollutants from the transportation sector. In this study, we analyse the economic benefit and feasibility of TE waste heat recovery systems in conventional vehicles operated in Korea by analytically modeling related vehicle systems and by analyzing driving patterns in urban environments. The economic effects of the associated efficiency improvement and the reduction of GHGs and air pollutants are simultaneously considered. Vehicular application of a TE generator may reduce 0.15 kL/year for a mid-size sedan and 1.04 kL/year for a medium-duty truck through fuel savings at a typical driving speed of 80 km/h. Based on the benefit–cost ratio analysis, it is shown that the economically acceptable costs of TE waste heat recovery systems are 744 $/kW for the mid-size sedan and 2905 $/kW for the medium-duty truck, respectively, when an operation period of 10 years is assumed. In terms of GHGs and air pollutants, the reduction annually amounts to 0.334 tCO2e of GHGs, 0.142 kg of CO, 0.00290 kg of VOC, 0.0150 kg of NO X , 0.198 kg of NH3, and 0.00006 kg of SO X for the mid-size sedan, while 2.65 tCO2e of GHGs, 1.974 kg of CO, 0.401 kg of VOC, 6.98 kg of NO X , 0.00034 kg of NH3, and 0.00229 kg of SO X can be annually reduced by applying a TE generator in the medium-duty truck.

We prepared a series of small molecules based on 7,7'-(4,4-bis(2-ethylhexyl)-4H-silolo[3,2-b:4,5-b']dithiophene-2,6-diyl)bis(4-(5'-hexyl-[2,2'-bithiophene]-5-yl)benzo[c][1,2,5]thiadiazole) with different fluorine substitution patterns (0F-4F). Depending on symmetricity and numbers of fluorine atoms incorporated in the benzo[c][1,2,5]thiadiazole unit, they show very different optical and morphological properties in a film. 2F and 4F, which featured symmetric and even-numbered fluorine substitution patterns, display improved molecular packing structures and higher crystalline properties in a film compared with 1F and 3F and thus, 2F achieved the highest OTFT mobility, which is followed by 4F. In the bulk heterojunction solar cell fabricated with PC71BM, 2F achieves the highest photovoltaic performance with an 8.14% efficiency and 0F shows the lowest efficiency of 1.28%. Moreover, the planar-type perovskite solar cell (PSC) prepared with 2F as a dopant-free hole transport material shows a high power conversion efficiency of 14.5% due to its high charge transporting properties, which were significantly improved compared with the corresponding PSC device obtained from 0F (8.5%). From the studies, it is demonstrated that low variation in the local dipole moment and the narrow distribution of 2F conformers make intermolecular interactions favorable, which may effectively drive crystal formations in the solid state and thus, higher charge transport properties compared with 1F and 3F.

In the past decade of robust innovation, the inverted organic solar cells (IOSCs) have been considered as a substitute photovoltaic technology with the potential to provide comparable power conversion efficiencies (PCEs) combined with low processing cost and ease in fabrication. The doping of metal oxides is an expedient technique for controlling the electronic band gap configurations of the electron buffer layer (EBL) in inverted organic solar cells for better performance. In addition, the sol-gel method is utilized for doping various functional materials as EBLs in IOSCs due to its cost effectiveness and uniform nanoscale film deposition. In this report, we analyzed the sol-gel-based ZnO films as EBLs for P3HT: PCBM based IOSCs. The ZnO film thickness was optimized and we studied the effect of lanthanum doping into the ZnO films by measuring the power conversion efficiency of the devices. In our study, lanthanum nitrate hexahydrate was selected as a potential lanthanum dopant. The IOSC device made with 1.57 atomic.%-lanthanum-doped ZnO (La-ZnO B) EBL showed a PCE of 4.34%, which is an increment of 12% as compared to the reference cell device containing a pure ZnO EBL. Therefore, we demonstrated that the lanthanum doping enhanced the interfacial electrical properties in terms of conductivity and carrier density.

Electron donor (D)–acceptor (A)-type conjugated polymers (CPs) have emerged as promising semiconductor candidates for organic field-effect transistors. Despite their high charge carrier mobilities, optimization of electrical properties of D–A-type CPs generally suffers from complicated post-deposition treatments such as high-temperature thermal annealing or solvent-vapor annealing. In this work, we report a high-mobility diketopyrrolopyrrole-based D–A-type CP nanowires, self-assembled by a simple but very effective solvent engineering method that requires no additional processes after film deposition. In situ grown uniform nanowires at room temperature were shown to possess distinct edge-on chain orientation that is beneficial for lateral charge transport between source and drain electrodes in FETs. FETs based on the polymer nanowire networks exhibit impressive hole mobility of up to 4.0 cm2 V–1 s–1. Moreover, nanowire FETs showed excellent operational stability in high temperature up to 200 °C because of...

A scanning transmission X-ray microscope is operational at the 10A beamline at the Pohang Light Source. The 10A beamline provides soft X-rays in the photon energy range 100–2000 eV using an elliptically polarized undulator. The practically usable photon energy range of the scanning transmission X-ray microscopy (STXM) setup is from ∼150 to ∼1600 eV. With a zone plate of 25 nm outermost zone width, the diffraction-limited space resolution, ∼30 nm, is achieved in the photon energy range up to ∼850 eV. In transmission mode for thin samples, STXM provides the element, chemical state and magnetic moment specific distributions, based on absorption spectroscopy. A soft X-ray fluorescence measurement setup has been implemented in order to provide the elemental distribution of thicker samples as well as chemical state information with a space resolution of ∼50 nm. A ptychography setup has been implemented in order to improve the space resolution down to 10 nm. Hardware setups and application activities of the STXM are presented.

In this paper, we describe the first tests of a dual-readout fiber calorimeter in which silicon photomultipliers are used to sense the (scintillation and Cherenkov) light signals. The main challenge in this detector is implementing a design that minimizes the optical crosstalk between the two types of fibers, which are located very close to each other and carry light signals that differ in intensity by about a factor of 60. The experimental data, which were obtained with beams of high-energy electrons and muons as well as in lab tests, illustrate to what extent this challenge was met. The Cherenkov light yield, a limiting factor for the energy resolution of this type of calorimeter, was measured to be about twice that of the previously tested configurations based on photomultiplier tubes. The lateral profiles of electromagnetic showers were measured on a scale of millimeters from the shower axis and significant differences were found between the profiles measured with the scintillating and the Cherenkov fibers., Accepted for publication in Nuclear Instruments and Methods in Physics Research A (29 pages, 19 figures)

We synthesized a solution-processable low band gap small molecule, Si1TDPP-EE-COC6, for use as a semiconducting channel material in organic thin film transistors (OTFTs). The Si1TDPP-EE-COC6 is composed of electron-rich thiophene–dithienosilole–thiophene (Si1T) units and electron-deficient diketopyrrolopyrrole (DPP) and carbonyl units. SiTDPP-EE-COC6-based OTFTs with Au source/drain electrodes were fabricated, and their electrical properties were systematically investigated with increasing thermal annealing temperature. The hole and electron mobilities of as-spun Si1TDPP-EE-COC6 were 3.3 × 10–4 and 1.7 × 10–4 cm2 V–1 s–1, respectively. The carrier mobilities increased significantly upon thermal annealing at 150 °C, yielding a hole mobility of 0.003 cm2 V–1 s–1 and an electron mobility of 0.002 cm2 V–1 s–1. The performance enhancement upon thermal annealing was strongly associated with the formation of a layered edge-on structure and a reduction in the π–π intermolecular spacing. Importantly, the use of at...

A highly flexible and transparent conductive electrode based on consecutively stacked layers of conductive polymer (CP) and silver nanowires (AgNWs) fully embedded in a colorless polyimide (cPI) is achieved by utilizing an inverted layer-by-layer processing method. This CP-AgNW composite electrode exhibits a high transparency of >92% at wavelengths of 450–700 nm and a low resistivity of 7.7 Ω ◻−1, while its ultrasmooth surface provides a large contact area for conductive pathways. Furthermore, it demonstrates an unprecedentedly high flexibility and good mechanical durability during both outward and inward bending to a radius of 40 μm. Subsequent application of this composite electrode in organic solar cells achieves power conversion efficiencies as high as 7.42%, which represents a significant improvement over simply embedding AgNWs in cPI. This is attributed to a reduction in bimolecular recombination and an increased charge collection efficiency, resulting in performance comparable to that of indium tin oxide-based devices. More importantly, the high mechanical stability means that only a very slight reduction in efficiency is observed with bending (

High-mobility and low-voltage-operated organic field-effect transistors (OFETs) are demonstrated by the design of a new fluorinated benzothiadiazole-based conjugated polymer with fluorinated high-k polymer dielectrics. A record-breaking high hole mobility of 9.0 cm(2) V(-1) s(-1) for benzothiadiazole-based semiconducting polymers is achieved by the excellent planarity of the semiconducting polymer.

To achieve commercialization and widespread application of next-generation photovoltaics, it is important to develop flexible and cost-effective devices. Given this, the elimination of expensive transparent conducting oxides (TCO) and replacement of conventional glass substrates with flexible plastic substrates presents a viable strategy to realize extremely low-cost photovoltaics with a potentially wide applicability. To this end, we report a completely TCO-free and flexible dye-sensitized solar cell (DSSC) fabricated on a plastic substrate using a unique transfer method and back-contact architecture. By adopting unique transfer techniques, the working and counter electrodes were fabricated by transferring high-temperature-annealed TiO2 and Pt/carbon films, respectively, onto flexible plastic substrates without any exfoliation. The fabricated working electrode with the conventional counter electrode exhibited a record efficiency for flexible DSSCs of 8.10%, despite its TCO-free structure. In addition, the completely TCO-free and flexible DSSC exhibited a remarkable efficiency of 7.27%. Furthermore, by using an organic hole-transporting material (spiro-MeOTAD) with the same transfer method, solid-state flexible TCO-free DSSCs were also successfully fabricated, yielding a promising efficiency of 3.36%.

Aim To determine the root canal anatomy of mandibular second molars in a Korean population by analysing cone-beam computed tomography (CBCT) images. Methodology The CBCT images of 960 subjects were examined. The number and configuration of roots and canals were categorized according to Vertucci's and modified Melton's classifications. Results Of the 1920 mandibular second molars, 41% had one root, 58% had two roots, and

Bottom-contact bottom-gate organic field-effect transistors (OFETs) are fabricated using a low band gap pDTTDPP-DT polymer as a channel material and single-layer graphene (SLG) or Au source/drain electrodes. The SLG-based ambipolar OFETs significantly outperform the Au-based ambipolar OFETs, and thermal annealing effectively improves the carrier mobilities of the pDTTDPP-DT films. The difference is attributed to the following facts: (i) the thermally annealed pDTTDPP-DT chains on the SLG assume more crystalline features with an edge-on orientation as compared to the polymer chains on the Au, (ii) the morphological features of the thermally annealed pDTTDPP-DT films on the SLG electrodes are closer to the features of those on the gate dielectric layer, and (iii) the SLG electrode provides a flatter, more hydrophobic surface that is favorable for the polymer crystallization than the Au. In addition, the preferred carrier transport in each electrode-based OFET is associated with the HOMO/LUMO alignment relative to the Fermi level of the employed electrode. All of these experimental results consistently explain why the carrier mobilities of the SLG-based OFET are more than 10 times higher than those of the Au-based OTFT. This work demonstrates the strong dependence of ambipolar carrier transport on the source/drain electrode and annealing temperature.

Highly oriented single-crystalline ferromagnetic Co nanowire (NW) arrays were synthesized on sapphire substrates via a single-step chemical vapor deposition (CVD) method. On an m-cut sapphire substrate, Co NWs were vertically grown in epitaxial relationship with the substrate without using any catalysts or templates. On an r-cut sapphire substrate, Co NWs were horizontally grown in two perpendicular directions. Furthermore, we report that the Co NWs were transformed into Co3O4 nanotubes by thermal annealing under dilute O2 conditions. Such formation of hollow structures is ascribed to favored outward diffusion of Co ions. The present vertically aligned arrays of single-crystalline Co NWs could be utilized for advanced magnetic memory applications owing to their uniform orientations.

In this Article, low-bandgap pTTDPP-BT polymers based on electron-accepting pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione (DPP) and benzothiadiazole (BT) and electron-donating thienothiophene (TT) moieties were synthesized. Phototransistors have been fabricated using ambipolar-behaving pTTDPP-BT polymers as active channel materials. The electrical and photoresponsive properties of the pTTDPP-BT phototransistors were strongly dependent on the film annealing temperature. As-spun pTTDPP-BT phototransistors exhibited a low hole mobility of 0.007 cm2/(V·s) and a low electron mobility of 0.005 cm2/(V·s), which resulted in low photocurrent detection due to the limited transport of the charge carriers. Thermal treatment of the polymer thin films led to a significant enhancement in the carrier mobilities (hole and electron mobilities of 0.066 and 0.115 cm2/(V·s), respectively, for 200 °C annealing) and thus significantly improved photoresponsive properties. The 200 °C-annealed phototransistors showed a wide-range wavelen...

Organic solar cells utilizing a P3HT/PCBM bilayer ( BL ) as their photoactive layer are fabricated using a sequential solution process. The film morphology and solar cell performance are investigated by changing the thickness of PCBM layer. The power conversion efficiency (PEC) of a BL solar cell strongly depends on the thickness of the PCBM layer; this value increases significantly after thermal annealing above the glass transition temperature of the P3HT. Based on the water contact angle and photoluminescence (PL) measurements, most of the PCBM was diffused into the amorphous P3HT region after thermal annealing. The external quantum efficiency spectrum reveals that the morphology of the P3HT in the BL solar cell is crystalline, even without thermal annealing, in contrast to the bulk heterojunction films. Moreover, thermal annealing improves charge collection efficiency by generating crystalline P3HT and PCBM domains. The transient photovoltage experiments suggest that the morphology of P3HT and PCBM in the BL solar cell reduces the charge recombination better than that in the BHJ solar cell. The BL solar cell exhibits a PEC of 3.54%, similar to that of the BHJ solar cell.

As a p-type semiconducting oxide that can absorb visible light, cuprous oxide (Cu2O) is an attractive material for solar energy conversion. This work introduces a high-temperature, vapor-phase synthesis that produces faceted Cu2O nanowires that grow epitaxially along the surface of a lattice-matched, single-crystal MgO substrate. Individual wires were then fabricated into single-wire, all-oxide diodes and solar cells using low-temperature atomic layer deposition (ALD) of TiO2 and ZnO films to form the heterojunction. The performance of devices made from pristine Cu2O wires and chlorine-exposed Cu2O wires was investigated under one-sun and laser illumination. These faceted wires allow the fabrication of well-controlled heterojunctions that can be used to investigate the interfacial properties of all-oxide solar cells.

We characterized the electrical properties of a field-effect transistor (FET) and a nonvolatile memory device based on a solution-processable low bandgap small molecule, Si1TDPP-EE-C6. The small molecule consisted of electron-rich thiophene-dithienosilole-thiophene (Si1T) units and electron-deficient diketopyrrolopyrrole (DPP) units. The as-spun Si1TDPP-EE-C6 FET device exhibited ambipolar transport properties with a hole mobility of 7.3×10(-5) cm2/(Vs) and an electron mobility of 1.6×10(-5) cm2/(Vs). Thermal annealing at 110 °C led to a significant increase in carrier mobility, with hole and electron mobilities of 3.7×10(-3) and 5.1×10(-4) cm2/(Vs), respectively. This improvement is strongly correlated with the increased film crystallinity and reduced π-π intermolecular stacking distance upon thermal annealing, revealed by grazing incidence X-ray diffraction (GIXD) and atomic force microscopy (AFM) measurements. In addition, nonvolatile memory devices based on Si1TDPP-EE-C6 were successfully fabricated by incorporating Au nanoparticles (AuNPs) as charge trapping sites at the interface between the silicon oxide (SiO2) and cross-linked poly(4-vinylphenol) (cPVP) dielectrics. The device exhibited reliable nonvolatile memory characteristics, including a wide memory window of 98 V, a high on/off-current ratio of 1×10(3), and good electrical reliability. Overall, we demonstrate that donor-acceptor-type small molecules are a potentially important class of materials for ambipolar FETs and nonvolatile memory applications.

We designed and synthetized a new poly{4,8-bis((2-ethylhexyl)thieno[3,2-b]thiophene)-benzo[1,2-b:4,5-b′]dithiophene-alt-2-ethylhexyl-4,6-dibromo-3-fluorothieno[3,4-b]thiophene-2-carboxylate} (PTTBDT-FTT) comprising bis(2-ethylhexylthieno[3,2-b]thiophenylbenzo[1,2-b:4,5-b′]dithiophene (TTBDT) and 2-ethylhexyl 3-fluorothieno[3,4-b]thiophene-2-carboxylate (FTT). The optical bandgap of PTTBDT-FTT was 1.55 eV. The energy levels of the highest occupied and lowest unoccupied molecular orbitals of PTTBDT-FTT were −5.31 and −3.73 eV, respectively. Two-dimensional grazing-incidence X-ray scattering measurements showed that the film’s PTTBDT-FTT chains are predominantly arranged with a face-on orientation with respect to the substrate, with strong π–π stacking. An organic thin-film transistor fabricated using PTTBDT-FTT as the active semiconductor showed high hole mobility of 2.1 × 10–2 cm2/(V·s). Single-junction bulk heterojunction photovoltaic cells with the configuration ITO/PEDOT:PSS/PTTBDT-FTT:PC71BM/Ca/Al were...

We report a highly sensitive detection method for anti-CCP autoantibodies using a SERS-based magnetic immunosensor. The proposed immunoassay technique is expected to be a new clinical tool for the early diagnosis of rheumatoid arthritis (RA).

The main concern of user-guided segmentation (UGS) is to achieve high segmentation accuracy with minimal user interaction. A novel convolutional neural network (CNN)-based UGS method is proposed, which employs a single click as the user interaction. In the proposed method, the input image in the Cartesian coordinate system is first converted into the polar transformed image with the user-guided point (UGP) as the origin of the polar coordinate system. The transformed image not only effectively delivers the UGP to the CNN, but also enables a single-scale convolution kernel to act as a multi-scale kernel, whose receptive field in the Cartesian coordinate system is altered based on the UGP without any extra parameters. In addition, a feature selection module (FSM) is introduced and utilised to additionally extract radial and angular features from the polar transformed image. Experimental results demonstrate that the proposed CNN using the polar transformed image improves the segmentation accuracy (mean intersection over union) by 3.69% on PASCAL VOC 2012 dataset compared with the CNN using the Cartesian coordinate image. The FSM achieves additional performance improvement of 1.32%. Moreover, the proposed method outperforms the conventional non-CNN-based UGS methods by 12.61% on average.

The open-circuit voltage of bulk heterojunction polymer solar cells utilizing 1,8-diiodooctane (DIO) as a processing additive was greatly improved by using an organic layer coated TiO 2 nanoparticle interfacial layer inserted between the active layer and the Al electrode. The transient photovoltage measurement revealed that there was significant non-geminate recombination at the DIO-processed active layer/Al electrode interface. Reduced open-circuit voltage ( V OC ) of the photovoltaic devices and high water contact angle of the DIO-processed active layer showed that the DIO-processed active layer has an undesirable surface composition for the electron collection. The organic layer coated TiO 2 nanoparticle interfacial layer effectively prevented the non-geminate recombination at the active layer/Al interface. As a result, we were able to significantly improve the V OC and power conversion efficiency from 0.46 V and 2.13% to 0.62 V and 3.95%, respectively.

We report a promising approach to fabricate organic–inorganic hybrid tandem photovoltaic devices with a reversed configuration. High bandgap hydrogenated amorphous silicon (a-Si:H) was deposited with plasma-enhanced chemical vapor deposition onto a solution-processed low bandgap organic photovoltaic (OPV) subcell. Two important factors for efficient tandem solar cells, interfacial series resistance (RS,int) and balanced photocurrents, were investigated. The intimate interfacial contact eliminated the RS,int, and sufficient transmittance of the OPV front subcell led to the well-balanced photocurrents. As a result, this reversed hybrid tandem device showed an enhanced efficiency of 3.3% and an open-circuit voltage of 1.51 V.

Nanomechanical resonators were fabricated using defect-free single-crystalline Au nanowires (NWs), and their mechanical properties were investigated by using the magneto-motive detection method. The fabricated Au NW resonators exhibited a resonance frequency of 33–119 MHz and a quality factor of 1800 ∼ 11000, depending on the resonator’s dimensions. Compared to its amorphous film counterpart, the Au NW resonator showed noticeable increases in both the resonance frequency and the quality factor. Also observed was a significant increase in the dynamic range for the NW resonator. These improvements could be attributed to low and uniform energy dissipation by the defect-free single-crystalline Au NW resonator. In addition, the length dependence of the nonlinear characteristics was observed. Mechanical softening was observed in the case of short (l = 2 µm and 3 µm) resonators while mechanical hardening was observed in the case of long (l = 4 µm) resonators.

Although 30–50 % of patients with brain tumors experience epileptic seizure as the presenting clinical symptom, and another 10–30 % are at risk for developing epilepsy in the later stages of the disease, the mechanisms of tumor-related epileptogenesis are poorly understood. We used magnetoencephalography (MEG) to investigate sensory evoked fields (SEFs) in patients with frontal lobe brain tumors as a means of evaluating the neuronal activity of peri-tumoral cortex. Twelve patients with frontal lobe brain tumors underwent MEG. We calculated the equivalent current dipole strength of two components of the primary sensory cortical response (N20m and P35m) and compared the P35m/N20m ratio in the tumor hemisphere vs. the normal hemisphere. There were two subsets of patients: group I, in which P35m/N20m was higher in the tumor hemisphere (n = 7), and group II, in which P35m/N20m was higher in the normal hemisphere (n = 5). We looked for associations between clinical factors and P35m/N20m within each group. All patients with seizure presentation were in group I, whereas only two patients without seizure presentation were in group I (Fisher exact test, p = 0.028). No other clinical factors were related to P35m/N20m. The mean ratio of P35m/N20m equivalent current dipole strength in patients with seizure presentation was 4.07 ± 2.38 in the tumor hemisphere and 2.00 ± 0.55 in the normal hemisphere. This difference was statistically significant (Mann-Whitney test, p = 0.030). The paradoxical increase in P35m/N20m in patients with seizure presentation suggests that decreased inhibitory neuronal activity is a potential cause of tumor-related epilepsy.