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Extrasensory neuromorphic devices that can recognize, memorize, and learn stimuli imperceptible to human beings are of considerable interest in interactive intelligent electronics research. This study presents an artificially intelligent magnetoreceptive synapse inspired by the magnetocognitive ability used by birds for navigation and orientation. The proposed synaptic platform is based on arrays of ferroelectric field-effect transistors with air-suspended magneto-interactive top-gates. A suspended gate of an elastomeric composite with superparamagnetic particles laminated with an electrically conductive polymer is mechanically deformed under a magnetic field, facilitating control of the magnetic-field-dependent contact area of the suspended gate with an underlying ferroelectric layer. The remanent polarization of the ferroelectric layer is electrically programmed with the deformed suspended gate, resulting in analog conductance modulation as a function of the magnitude, number, and time interval of the input magnetic pulses. The proposed extrasensory magnetoreceptive synapse may be used as an artificially intelligent synaptic compass that facilitates barrier-adaptable navigation and mapping of a moving object.

The growth control of a molybdenum disulfide (MoS2) thin film, including the number of layers, growth rate, and electrical property modulation, remains a challenge. In this study, we synthesized MoS2 thin films using the metal-organic chemical vapor deposition (MOCVD) method with a 2 inch wafer scale and achieved high thickness uniformity according to the positions on the substrate. In addition, we successfully controlled the number of MoS2 layers to range from one to five, with a growth rate of 10 min per layer. The layer-dependent optical and electrical properties were characterized by photoluminescence, Raman spectroscopy, differential reflectance spectroscopy, and field effect transistors. To guide the growth of MoS2, we summarized the relation between the growth aspects and the precursor control in the form of a growth map. Reference to this growth map enabled control of the growth rate, domain density, and domain size according to the application purposes. Finally, we confirmed the electrical performance of MOCVD-grown MoS2 with five layers under a high-κ dielectric environment, which exhibited an on/off current ratio of 10∼6 and a maximum field effect mobility of 8.6 cm2 V-1 s-1.

MXenes (Ti3C2TX) are two-dimensional transition-metal carbides and carbonitrides with high conductivity and optical transparency. However, transparent MXene electrodes with high environmental stability suitable for various flexible organic electronic devices have rarely been demonstrated. By laminating a thin polymer film onto a solution-processed MXene layer to protect the MXene film from harsh environmental conditions, we present transparent and flexible MXene electronic devices. A thin polymer layer spin-coated onto a transparent MXene electrode provides environmental stability even under air exposure longer than 7 d at high temperatures (up to 70 °C) and humidity levels (up to 50%) without degrading the transparency of the electrode. The resulting polymer-laminated (PL) MXene electrode facilitates the development of a variety of field-driven photoelectronic devices by exploiting the electric field exerted between the MXene layer and the counter electrode through the insulating polymer. Field-induced electroluminescent displays, based on both organic and inorganic phosphors, with PL-MXene electrodes are demonstrated with high transparency and mechanical flexibility. Furthermore, our PL-MXene electrode exhibits high versatility through successful implementation in capacitive-type pressure sensors and triboelectric nanogenerators, resulting in field-driven sensing and energy harvesting electronic devices with excellent operation reliability.

Two-dimensional (2D) materials have recently provided a new perspective on optoelectronics because of their unique layered structure and excellent physical properties. However, their potential use as optoelectric devices has been limited by the trade-off between photoresponsivity and response time. Here, based on a vertically stacked atomically thin p-n junction, we propose a gap-mode plasmon structure that simultaneously enables enhanced responsivity and rapid photodetection. The atomically thin 2D materials act as a spacer for enhancing the gap-mode plasmons, and their short transit length in the vertical direction allows fast photocarrier transport. We demonstrate a high responsivity of up to 8.67 A/W with a high operation speed that exceeds 35 MHz under a 30 nW laser power. Spectral photocurrent, absorption, and a numerical simulation are used to verify the effectiveness of the gap-mode plasmons in the device. We believe that the design strategy proposed in this study can pave the way for a platform to overcome the trade-off between responsivity and response time.

In this study, technology computer-aided design (TCAD) was used to investigate carrier selective contact solar cell performance based on the boundary of tunneling oxide and electron selective contact layer properties. The role of tunneling oxide quality in the passivation and inter-diffusion properties of the plasma-enhanced chemical vapor deposition of phosphorus-doped amorphous silicon as an electron selective contact layer is studied for carrier selective contact solar cells. Tunnel oxide quality varies according to the ratio of Si4+ to Si2+ state. For the Si4+/Si2+ ratio of 4, open-circuit voltage of 730 mV and the lowest interface trap density of 5.3 × 1010 cm−2 eV−1 are achieved. The change in diffusion depth of the doped layer with respect to the annealing temperature is analysed by transmission electron microscopy (TEM)/energy dispersive X-ray spectroscopy (EDS) measurement. Carrier selective contact solar cell parameters are optimized by incorporating the experimental values of interface trap density, inter-diffused impurity concentration, and depth in the Quokka 3 TCAD tool. Solar cell conversion efficiency of 24.31% was obtained. To understand the response of carrier selective solar cell to the environmental changes, the output characteristics of the solar cell were studied by varying the illumination temperature by 10% of the standard test conditions (STC) and temperature from 277 K to 377 K (difference of 100 K).

Ecofriendly cation metal oxide quantum dots (QDs) are one of the promising candidates to replace for QDs containing expensive indium (In) or hazardous Cd- and Pb-elements. Super-Eg excitation wavel...

This work demonstrates a high-performance and hysteresis-free field-effect transistor based on two-dimensional (2D) semiconductors featuring a van der Waals heterostructure, MoS2 channel, and GaS gate insulator. The transistor exhibits a subthreshold swing of 63 mV/dec, an on/off ratio over 106 within a gate voltage of 0.4 V, and peak mobility of 83 cm2/(V s) at room temperature. The low-frequency noise characteristics were investigated and described by the Hooge mobility fluctuation model. The results suggest that the van der Waals heterostructure of 2D semiconductors can produce a high-performing interface without dangling bonds and defects caused by lattice mismatch. Furthermore, a logic inverter and a NAND gate are demonstrated, with an inverter voltage gain of 14.5, which is higher than previously reported by MoS2-based transistors with oxide dielectrics. Therefore, this transistor based on van der Waals heterostructure exhibits considerable potential in digital logic applications with low-power integrated circuits.

Human-interactive displays (HIDs) facilitate the visualization of sensible information such as touch, smell, and sound and have attracted significant interest owing to their potential in emerging IoT-connected wearable electronics. Furthermore, the visualization of phenomena that is rarely sensible, such as magnetic fields, ultrasonic waves, and odorless toxic gases or liquids, can further broaden the utilization of HIDs. Field-induced electroluminescence (EL) of either organic or inorganic fluorescent materials under alternating current (AC) has been extensively studied and its unique device architecture in which an emitting layer is separated with an insulator from electrode offers a new platform for designing and developing emerging HIDs. Here, we present various sensory and extra-sensory interactive displays based on AC EL.

In our study, to optimize the electron–hole balance through controlling the electron transport layer (ETL) in the QD-LEDs, four materials (ZnO, ZnGaO, ZnMgO, and ZnGaMgO NPs) were synthesized and applied to the QD-LEDs as ETLs. By doping ZnO NPs with Ga, the electrons easily inject due to the increased Fermi level of ZnO NPs, and as Mg is further doped, the valence band maximum (VBM) of ZnO NPs deepens and blocks the holes more efficiently. Also, at the interface of QD/ETLs, Mg reduces non-radiative recombination by reducing oxygen vacancy defects on the surface of ZnO NPs. As a result, the maximum luminance (Lmax) and maximum luminance efficiency (LEmax) of QD-LEDs based on ZnGaMgO NPs reached 43 440 cd m−2 and 15.4 cd A−1. These results increased by 34%, 10% and 27% for the Lmax and 450%, 88%, and 208% for the LEmax when compared with ZnO, ZnGaO, and ZnMgO NPs as ETLs.

Objective The aim of this study was to describe magnetic resonance imaging findings of newly categorized ovarian seromucinous tumors. Methods We retrospectively reviewed the images of 29 patients with seromucinous tumor for the following factors: size, configuration, signal intensity (SI), and accompanying ovarian endometriosis. Results Thirty-two tumors (17 benign, 7 borderline, 8 carcinoma) were found on computed tomography or magnetic resonance imaging. Their mean size was 11.4 cm. Benign tumors appeared as unilocular or multilocular cystic masses. Borderline tumors and carcinomas appeared as complex cystic-solid masses. T2-weighted SI of the solid portion was hyperintense in borderline tumors and intermediate in carcinomas. Endometriosis was present in 18 tumors, and hemorrhage (on images) in 20. Conclusions The imaging features of seromucinous tumors varied by tumor type. More than half of tumors were accompanied by endometriosis. High T2-weighted SI of the solid portion could be a specific feature of borderline tumors. It is hard to differentiate seromucinous carcinomas from other endometriosis-related carcinomas.

Ternary metal-oxy-chalcogenides are emerging as next-generation layered semiconductors beyond binary metal-chalcogenides (i.e., MoS2). Among ternary metal-oxy-chalcogenides, especially Bi2O2Se has been demonstrated in field-effect transistors and photodetectors, exhibiting ultrahigh performance with robust air stability. The growth method for Bi2O2Se that has been reported so far is a powder sublimation based chemical vapor deposition. The first step for pursuing the practical application of Bi2O2Se as a semiconductor material is developing a gas-phase growth process. Here, we report a cracking metal-organic chemical vapor deposition (c-MOCVD) for the gas-phase growth of Bi2O2Se. The resulting Bi2O2Se films at very low growth temperature (∼300 °C) show single-crystalline quality. By taking advantage of the gas-phase growth, the precise phase control was demonstrated by modulating the partial pressure of each precursor. In addition, c-MOCVD-grown Bi2O2Se exhibits outstanding electrical and optoelectronic performance at room temperature without passivation, including maximum electron mobility of 127 cm2/(V·s) and photoresponsivity of 45134 A/W.

We develop a non-lithographic method for fabricating ordered micro/nanostructures of polymer thin films based on controlled dewetting of the films on topographically pre-patterned substrates with a large area. An ordered nanopattern of polystyrene (PS) is accomplished by thermal treatment of a thin PS film above its Tg spin coated on a topographically patterned substrate. We investigate the influence of pattern geometry on the final morphology of the dewetted polymer films using both mesa and indent patterned substrates. The controlled dewetting, initiated preferentially at the edges of individual pre-patterned mesas, in particular gives rise to spherical cap domains located at the center of the mesas. The domains are much smaller than the individual mesas as a consequence of the significant pattern reduction to nearly 300%. The arrays of 70 nm PS nano-sphere caps are obtained from arrays of 200 nm square pre-patterned mesas. Our method is also applicable for other polymers such as a poly(4-vinyl pyridine) (P4VP) containing Rhodamine 6G (Rh6G) dye on a pre-patterned PS substrate and successfully produced highly fluorescent stable nanopatterned films.

Lightweight and flexible tactile learning machines can simultaneously detect, synaptically memorize, and subsequently learn from external stimuli acquired from the skin. This type of technology holds great interest due to its potential applications in emerging wearable and human‐interactive artificially intelligent neuromorphic electronics. In this study, an integrated artificially intelligent tactile learning electronic skin (e‐skin) based on arrays of ferroelectric‐gate field‐effect transistors with dome‐shape tactile top‐gates, which can simultaneously sense and learn from a variety of tactile information, is introduced. To test the e‐skin, tactile pressure is applied to a dome‐shaped top‐gate that measures ferroelectric remnant polarization in a gate insulator. This results in analog conductance modulation that is dependent upon both the number and magnitude of input pressure‐spikes, thus mimicking diverse tactile and essential synaptic functions. Specifically, the device exhibits excellent cycling stability between long‐term potentiation and depression over the course of 10 000 continuous input pulses. Additionally, it has a low variability of only 3.18%, resulting in high‐performance and robust tactile perception learning. The 4 × 4 device array is also able to recognize different handwritten patterns using 2‐dimensional spatial learning and recognition, and this is successfully demonstrated with a high degree accuracy of 99.66%, even after considering 10% noise., An artificially intelligent electronic skin that is capable of sensing and learning tactile stimuli is presented. This ferroelectric field effect transistor platform can implement spatial sensory synaptic functions through electrical and/or tactile spikes without complicated integration. These unique characteristics enable the demonstrated device array to recognize different handwriting patterns with a high degree of accuracy, similar to biological neural networks.

A 3D touchless display is created where a human finger position is visualized in structural colors of a soft photonic crystal., The development of a lightweight, low-power, user-interactive three-dimensional (3D) touchless display in which a human stimulus can be detected and simultaneously visualized in noncontact mode is of great interest. Here, we present a user-interactive 3D touchless sensing display based on multiorder reflection structural colors (SCs) of a thin, solid-state block copolymer (BCP) photonic crystal (PC). Full-visible-range SCs are developed in a BCP PC consisting of alternating lamellae, one of which contains a chemically cross-linked, interpenetrated hydrogel network. The absorption of a nonvolatile ionic liquid into the domains of the interpenetrated network allows for further manipulation of SC by using multiple-order photonic reflections, giving rise to unprecedented visible SCs arising from reflective color mixing. Furthermore, by using a hygroscopic ionic liquid ink, a printable 3D touchless interactive display is created where 3D position of a human finger is efficiently visualized in different SCs as a function of finger-to-display distance.

Development of a human-interactive display enabling the simultaneous sensing, visualisation, and memorisation of a magnetic field remains a challenge. Here we report a skin-patchable magneto-interactive electroluminescent display, which is capable of sensing, visualising, and storing magnetic field information, thereby enabling 3D motion tracking. A magnetic field-dependent conductive gate is employed in an alternating current electroluminescent display, which is used to produce non-volatile and rewritable magnetic field-dependent display. By constructing mechanically flexible arrays of magneto-interactive displays, a spin-patchable and pixelated platform is realised. The magnetic field varying along the z-axis enables the 3D motion tracking (monitoring and memorisation) on 2D pixelated display. This 3D motion tracking display is successfully used as a non-destructive surgery-path guiding, wherein a pathway for a surgical robotic arm with a magnetic probe is visualised and recorded on a display patched on the abdominal skin of a rat, thereby helping the robotic arm to find an optimal pathway., Designing human-interactive displays enabling the simultaneous sensing, visualization, and memorization of a magnetic field remains a challenge. Here, the authors present a skin-patchable magneto-interactive electroluminescent display by employing a magnetic field-dependent conductive gate, thereby enabling 3D motion tracking.

Second shot arterial phase (SSAP) imaging is an additional arterial phase image obtained by re-injecting a small amount of contrast medium after routine dynamic imaging in gadoxetic acid-enhanced liver MRI. We aimed to evaluate the feasibility and additional value of a SSAP image in gadoxetic acid-enhanced liver MRI. One hundred seventy-two patients who underwent SSAP imaging after re-injection of 4 mL of contrast material after routine dynamic imaging (original) in gadoxetic acid-enhanced liver MRIs were included. Motion artifacts on arterial phase (AP) images were rated using a 5-point scale and were compared between the original AP images and SSAP images. We evaluated visual detection rates of arterial hypervascularity on the original AP and SSAP images and their subtraction images in patients with hypervascular hepatocellular carcinoma (HCC). The motion artifact of the SSAP images was significantly lower than that of the original AP images (mean score, 1.76 vs 2.06; p

Two-dimensional (2D) nanosheets of transition metal dichalcogenides (TMDs) are of significant interest for potential photoelectronic applications. However, the fabrication of solution-processed arrays of mechanically flexible thin TMD films-based vertical type p–n junction photodetectors over a large area is a great challenge. Our method is based on controlled solvent evaporation of MoSe2 suspension spread on water surface. Single or few-layered MoSe2 nanosheets modified with the dispersant amine-terminated poly(styrene) (PS-NH2) were homogeneously deposited and stacked on water upon solvent evaporation, giving rise to uniform MoSe2/PS-NH2 composite films that can be readily transferred onto other substrates. A p–n junction vertical diode of Al/p-type Si/p-type poly(9,9-di-n-octylfluorenyl-2,7-diyl)/n-type MoSe2 composite/Au stacked from bottom to top exhibited characteristic rectifying current behavior upon voltage sweep with a rectification ratio of 103. Subsequent illumination of near-infrared light on...

In c-Si solar cells, surface recombination velocity increases as the wafer thickness decreases due to an increase in surface to volume ratio. For high efficiency, in addition to low surface recombination velocity at the rear side, a high internal reflection from the rear surface is also required. The SiOxNy film with low absorbance can act as rear surface reflector. In this study, industrially feasible SiO2/SiOxNy stack for rear surface passivation and screen printed local aluminium back surface field were used in the cell structure. A 3 nm thick oxide layer has resulted in low fixed oxide charge density of 1.58 × 1011 cm−2 without parasitic shunting. The oxide layer capped with SiOxNy layer led to surface recombination velocity of 155 cm/s after firing. Using single layer (SiO2) rear passivation, an efficiency of 18.13% has been obtained with Voc of 625 mV, Jsc of 36.4 mA/cm2 and fill factor of 78.7%. By using double layer (SiO2/SiOxNy stack) passivation at the rear side, an efficiency of 18.59% has been achieved with Voc of 632 mV, Jsc of 37.6 mA/cm2, and fill factor of 78.3%. An improved cell performance was obtained with SiO2/SiOxNy rear stack passivation and local BSF.

We report femtosecond infrared laser-induced selective tailoring of carrier transport as well as surface morphology on a conducting polymer blend thin film. Maximal 2.4 times enhancement on vertical current transport in poly(3-hexylthiophene):phenyl-C61-butyric acid methyl ester, was achieved by this irradiation. The laser irradiation induced a photo expansion without deteriorating its molecular structure and the film morphology could be customized in the micron scale by adjusting the laser writing parameters. In the photoexpanded region, the face-on populations were about 2.2 times larger in comparison with the pristine region, which was a major contributor to the enhanced carrier transport.

Interactive displays involve the interfacing of a stimuli-responsive sensor with a visual human-readable response. Here, we describe a polymeric electroluminescence-based stimuli-responsive display method that simultaneously detects external stimuli and visualizes the stimulant object. This organic light-emitting board is capable of both sensing and direct visualization of a variety of conductive information. Simultaneous sensing and visualization of the conductive substance is achieved when the conductive object is coupled with the light emissive material layer on application of alternating current. A variety of conductive materials can be detected regardless of their work functions, and thus information written by a conductive pen is clearly visualized, as is a human fingerprint with natural conductivity. Furthermore, we demonstrate that integration of the organic light-emitting board with a fluidic channel readily allows for dynamic monitoring of metallic liquid flow through the channel, which may be suitable for biological detection and imaging applications., Kim et al. report a polymeric-based electroluminescent interactive display that actively detects and visualizes an external conductive object under an alternating current. Fingerprint visualization and dynamic monitoring of metallic liquid flow are demonstrated.

The development of pressure sensors that are effective over a broad range of pressures is crucial for the future development of electronic skin applicable to the detection of a wide pressure range from acoustic wave to dynamic human motion. Here, we present flexible capacitive pressure sensors that incorporate micropatterned pyramidal ionic gels to enable ultrasensitive pressure detection. Our devices show superior pressure-sensing performance, with a broad sensing range from a few pascals up to 50 kPa, with fast response times of

The incidence of detection of accessory hepatic vein (AHV) using MRI or CT has been reported. However, previous studies had a small sample size or only reported on the incidence of hepatic vein variants. To the best of our knowledge, there has been no previous report evaluating the factors predictive of the presence of an AHV. To evaluate the incidence and morphology of the accessory hepatic vein (AHV) using multidetector row computed tomography (MDCT) and to investigate the factors which may be helpful in predicting the presence of an AHV. We enrolled 360 patients who underwent abdominal MDCT. We investigated whether the AHV was present and evaluated the frequency of AHVs greater than 5 mm in diameter. We classified the morphology of the AHV entering the inferior vena cava (IVC). We also examined the factors that predicted the presence of an AHV by comparing the diameter of the middle hepatic vein (MHV) and the right hepatic vein (RHV). We identified an AHV in 164 of the 360 patients (45.6 %). Among the 164 AHVs, 56.7 % were larger than 5 mm in diameter. The most common morphologies of the inferior RHV were a single main trunk (58.5 %), followed by two main trunks with a V-shape (19.5 %) and two trunks entering the IVC separately (17.0 %). The possibility that an AHV will be present was significantly higher when the diameter of the RHV was smaller than that of the MHV. MDCT can provide important information regarding AHV incidence and morphology. The possibility of an AHV being present was significantly higher when the diameter of the RHV was smaller than that of the MHV.

Fabrication of highly flexible, inverted, indium tin oxide (ITO)-free top-emitting quantum-dot light-emitting diodes (QDLEDs) on elastic polyurethane (PU) substrates is reported here. To cope with the irregular surfaces of the PU substrate, polyvinyl alcohol (PVA) is used as a buffer layer. By adopting the PVA buffer layer, we demonstrate red-color and green-color top-emitting QDLEDs that show turn-on voltages from 4.0 V to 4.5 V, and maximum luminance values of 1200 cd m−2 (red) and 4800 cd m−2 (green). In addition, when the QDLEDs are stuck on the curved surfaces (vials and a tumbler), the devices still exhibit a clear light emission. These highly flexible QDLEDs can pave the way for further development of next-generation wearable or attachable displays, or solid-state lighting.

Polymer light-emitting diodes (PLEDs) have been of great interest for flexible mobile displays and large area solid-state lighting due to the possibility of achieving low production costs using solution processes combined with various printing technologies. Although monochromatic operation of PLEDs with high luminous efficiency and device stability has been achieved using numerous strategies, the development of color-tunable PLEDs capable of emitting a broad range of light upon the application of external stimuli still remains challenging. Here, we present a solution-processed broad range color-tunable tandem PLED of inverted and regular light emitting units (LEUs) stacked in series sharing a floating polymer electrode as a charge injection layer between two LEUs. Fine and broad wavelength color control from pure blue to pure orange is achieved when an AC field is applied with different positive-to-negative polarity heights in our tandem PLED. Our AC-driven tandem PLEDs offer a facile route to color-tunable polymer EL devices with a maximum current efficiency (CE) and luminance of 2.5 cd A−1 and 1300 cd m−2 for blue emission under DC reverse and 6.7 cd A−1 and 6000 cd m−2 for orange emission under DC forward as well as 3.1 cd A−1 and 6000 cd m−2 for white emission under AC, respectively.

Cholesteric liquid crystals (CLCs) possess a photonic bandgap owing to the helical arrangement of molecules. The CLCs reflect circularly-polarized light of a specific handedness and wavelength, exhibiting colors. The wavelength of the selective reflection, or the structural color, can be easily controlled by varying the concentration of a chiral dopant. Although this unique optical property renders CLCs promising for various applications, their fluidity severely limits the ease of processing and their structural stability. To overcome this limitation, we designed CLC microparticles (CLC-MPs) via photopolymerization of reactive mesogens (RMs) in CLC droplets. Using capillary microfluidic devices, highly uniform emulsion drops of CLC-RM mixtures were prepared in aqueous phase drops, which were then exposed to ultraviolet (UV) irradiation to obtain solid microparticles. The diameter of the CLC-MPs can be precisely controlled by either manipulating the flow rates of the dispersed and continuous phases or varying the diameter of the capillary orifice in the microfluidic devices. The wavelength of reflection and the handedness of the helical structure are selected via the composition of the dispersed phase. The photo-polymerization of RMs leads to the formation of a three-dimensional rigid network, thereby yielding CLC-MPs with high mechanical stability. The CLC-MPs could be further assembled to form two-dimensional hexagonal arrays on flat surfaces or deposited in pre-defined trenches or holes via mechanical rubbing. Moreover, two distinct CLC-MPs with opposite handedness can be patterned to show different color graphics depending on the selection of handedness of circularly-polarized light, which are appealing for anti-forgery patches.

Poly(3-hexylthiophene) (P3HT) is a promising p-type polymer to optimize the architecture, charge transfer, and environmental stability in electronic devices. Therefore, it can be a suitable material for a hole transporting layer in lead halide perovskite solar cells (PSCs). However, the mismatch of band alignment with perovskites suppresses efficient charge extraction and transfer. This results in the significant loss of open-circuit voltage (Voc) and resultant device performance deterioration. Therefore, modifying the energy level is essential to improve band alignment with perovskites. Here, a cobalt complex, tris(2-(1H-pyrazol-1-yl)pyridine) cobalt(II) di[bis(trifluoromethane)sulfonimide] (Co(II)-TFSI) is used as a p-dopant in P3HT. This enhances the conductivity and leads to a downward shift of the energy levels. The efficient charge extraction and transfer from perovskite considerably improves the device performance, resulting in a power conversion efficiency (PCE) of 16.28% and Voc of 1.061 V. Moreover, a flexible device incorporating Co-P3HT exhibits impressive 11.84% PCE and mechanical stability up to 600 bending cycles. And the flexible Co-P3HT device shows better air stability than the Li-doped P3HT (Li-P3HT) device for 40 days. These results suggest that Co(II)-TFSI is an alternative to Li salts to realize high performance in PSCs incorporating polythiophene derivatives.

Stretchable alternating-current electroluminescent (ACEL) devices are required due to their potential in wearable, biomedical, e-skin, robotic, lighting, and display applications; however, one of the main hurdles is to achieve uniform electroluminescence with an optimal combination of transparency, conductivity, and stretchability in electrodes. We therefore propose a fabrication scheme involving strategically combining two-dimensional graphene layers with a silver nanowire (Ag NW)-embedded PEDOT:PSS film. The developed hybrid electrode overcomes the limitations of commonly known metallic NWs and ionic conductor-based electrodes for ACEL applications. Furthermore, the potential of the hybrid electrode is realized in demonstrating large-area stretchable ACEL devices composed of an 8 × 8 passive array. The prototype ACEL passive array demonstrates efficient and uniform electroluminescence under high levels of mechanical deformation such as bending, rolling, twisting, and stretching.

The first metastable phase Ag, ZnS: α-In2S3 QDs were synthesized by ultrafast light-material interaction. The multiple irradiation of millisecond flash pulses facilitated thermodynamic non-equilibrium superheating and quenching for metastable QD formation, as well as sequential self-formation of α-In2S3 QD nucleation, Ag-doping and ZnS-passivation by photo-responsive ionic kinetics. Upon multiple illumination of flash pulses, the synthesis mechanism of Ag, ZnS: α-In2S3 QD was experimentally proved by atomic-resolution transmission electron microscopy (AR-TEM), scanning TEM (STEM) and diverse spectral analysis. To verify the metastable phase QD formation by superheating/quenching in reaction solution, the localized surface plasmon (LSP) properties and instantaneous temperature increment were theoretically calculated using finite-difference time-domain (FDTD) method. Finally, optoelectronic performance and long-term stability of as-synthesized QDs were evaluated by demonstrating the broad wavelength metal-semiconductor-metal (MSM) photoelectric device.

Thin-film silicon solar cells are promising candidates for the low-cost production of electricity from sunlight. However, their efficiency remains relatively low, which is one of the major issues for their commercialisation. In the thin-film silicon technology, light trapping is an important design consideration for achieving a higher device efficiency. An advanced light-trapping technology is expected to boost the efficiency of solar cells further. Therefore, we investigated the development of an advanced light-trapping scheme in a two-dimensional periodic surface structure produced via inductively coupled plasma reactive-ion etching. The texture of the glass surface was varied under various plasma conditions. For the various shapes and sizes of the obtained surface texture, the increased height and base angle of the individual texture showed an overall increase in the diffused transmission of light. In some cases, the diffused transmission was as high as 89 % of the total light transmitted through the glass. The effect of the textured glass on a solar cell was investigated through simulation. Results show that the efficiency of a single-junction solar cell can be enhanced significantly when such a textured glass is used instead of a non-textured glass.

Two dimensional (2D) p-MoTe2 channel-based nonvolatile memory transistors with ferroelectric P(VDF-TrFE) polymer has been studied using a bottom-gate device architecture, which is introduced to dramatically reduce both of the switching and drain voltages to minimum 8 V and 10 mV, respectively. In fact, most of 2D-channel ferroelectric FETs with the same P(VDF-TrFE) polymer have used top-gate architectures, utilizing high switching pulse voltages over 20–25 V due to the existence of dead layer, which is unavoidably formed at the interface between P(VDF-TrFE) and thermal-deposited Al top gate. Key effects to realize such a low 8–13 V switching thus originate from the bottom-gate architecture. On the one hand, keys to obtain the low operation/drain voltage come from anneal-free Ohmic contact which is obtained using H2O2 solution. Thanks to the low operation voltages of 10 mV, consuming power in the nonvolatile FETs can be minimized to ~a few pW for OFF/Erase state and ~a few hundred pW for ON/Program although it eventually becomes ~nW and ~30 nW for OFF and ON states in a practical circuit operation to switch organic light emitting diodes. Our approaches of bottom-gate architecture and H2O2 contact nicely work even for transparent nonvolatile memory FET.

Two-dimensional (2D) materials present various extraordinary properties that are advantageous in optoelectronic devices with atomically thin nature. Despite their excellent light–matter interaction, a low optical absorption that is proportional to thickness is considered to be a major limitation. In this study, a gap-mode plasmon structure is applied to the Schottky junction of Au–MoS2 to compensate for its low absorption. The magnitude of the gap-mode plasmon is generally known to be inversely proportional to the gap distance between two metal nanostructures; hence, an atomically thin 2D material can be considered to be a good candidate for a gap spacer. Owing to the gap-mode plasmon structure, the photoresponsivity of the proposed device is enhanced by approximately 11.6 times from 25 to 290 A W−1 under 1 nW of laser power, without photoresponse time degradation. Two operation modes, named the photovoltaic and the photoconductive mode, are also observed through different response times; these present different carrier transport mechanisms depending on the existence of bias voltage.

The purpose of this work was to evaluate cases of benign ovarian mature teratoma (MT) with enhancing solid components on pelvic magnetic resonance imaging (MRI) and to correlate the MRI findings with the pathology reports. We retrospectively reviewed MRI findings and pathologic reports of 126 patients with pathologically confirmed ovarian MT. Enhancing solid components were observed in 24 (18.8%) of 128 benign MTs. The largest diameter ranged from 5.9 to 42.2 mm. The appearance was variable. Of 24 tumors, 19 (79.2%) had regular borders. On pathologic analysis, solid components of benign MTs were identified as glial tissue, thyroid tissue, fibrous stroma, or vessels.

Purpose To identify the most reliable imaging features for differentiating hepatocellular carcinoma with paradoxical uptake on the hepatobiliary phase (HCCpara) from focal nodular hyperplasia (FNH)-like nodules using Gd-EOB-DTPA-enhanced MRI. Materials and Methods This was a retrospective study. Twenty patients with HCCpara and 21 patients with FNH-like nodules were included. The following MRI features were evaluated using 3.0 Tesla unit by two radiologists: signal intensity (SI) on T1-, T2-, and diffusion-weighted imaging (DWI), arterial enhancement pattern, washout appearance on the portal venous phase (PVP) and/or transitional phase (TP), uptake pattern on the hepatobiliary phase (HBP), “T2 scar,” “EOB scar,” and chemical shift on in- and out-of-phase images. Multivariate logistic regression analysis was performed to assess MRI features for prediction of HCCpara. Results Compared with FNH-like nodules, HCCpara had significantly more frequent heterogeneous T1 SI (P

In this article we present a mechanism for creating metastable defects in intrinsic hydrogenated amorphous silicon (a-Si:H) layers by changing the flow-rate ratio of SiH4 and H2. This is an important cardinal property that restricts the performance of both solar cells and thin-film transistors (TFT). Light or electrical bias results in generation of metastable dangling bonds. We evaluated the gas flow-rate ratio dependence of current decrease before and after application of electrical bias stress. Furthermore, we produced an a-Si:H TFT for comparison with a single-layer a-Si:H. Intrinsic layers deposited by SiH4 to H2 flow-rate ratios of 1:3 exhibited greater resistance to stress. In a-Si:H single layer experiment, we got a similar result, samples with SiH4 and H2 flow-rate ratios of 1:3 exhibited less decrease in current after application of electrical bias stress. These results will facilitate fabrication of more-stable a- Si:H thin film p-i-n solar cells.

n-type PERT (passivated emitter, rear totally diffused) bifacial solar cells with boron and phosphorus diffusion as p+ emitter and n+ BSF (back surface field) have attracted significant research interest recently. In this work, the influences of wafer thickness, bulk lifetime, emitter, BSF on the photovoltaic characteristics of solar cells are discussed. The performance of the solar cell is determined by using one-dimensional solar cell simulation software PC1D. The simulation results show that the key role of the BSF is to decrease the surface doping concentration reducing the recombination and thus, increasing the cell efficiency. A lightly phosphorus doped BSF (LD BSF) was experimentally optimized to get low surface dopant concentration for n type bifacial solar cells. Pre-oxidation combined with a multi-plateau drive-in, using limited source diffusion was carried out before pre-deposition. It could reduce the surface dopant concentration with minimal impact on the sheet resistance.

Electroluminescence (EL) of organic and polymeric fluorescent materials programmable in the luminance is extremely useful as a non-volatile EL memory with the great potential in the variety of emerging information storage applications for imaging and motion sensors. In this work, a novel non-volatile EL memory in which arbitrarily chosen EL states are programmed and erased repetitively with long EL retention is demonstrated. The memory is based on utilizing the built-in electric field arising from the remnant polarization of a ferroelectric polymer which in turn controls the carrier injection of an EL device. A device with vertically stacked components of a transparent bottom electrode/a ferroelectric polymer/a hole injection layer/a light emitting layer/a top electrode successfully emits light upon alternating current (AC) operation. Interestingly, the device exhibits two distinctive non-volatile EL intensities at constant reading AC voltage, depending upon the programmed direct current (DC) voltage on the ferroelectric layer. DC programmed and AC read EL memories are also realized with different EL colors of red, green and blue. Furthermore, more than four distinguishable EL states are precisely addressed upon the programmed voltage input each of which shows excellent EL retention and multiple cycle endurance of more than 105 s and 102 cycles, respectively.

Minimizing the carrier recombination and electrical loss through surface passivation is required for high efficiency c-Si solar cell. Usually, SiNX, SiOX, SiONX and AlOX layers are used as passivation layer in solar cell application. Silicon oxide layer is one of the good passivation layer in Si based solar cell application. It has good selective carrier, low interface state density, good thermal stability and tunneling effect. Recently tunneling based passivation layer is used for high efficiency Si solar cell such as HIT, TOPCon and TRIEX structure. In this paper, we focused on silicon oxide grown by various the method (thermal, wet-chemical, plasma) and passivation effect in c-Si solar cell.

The aims of this study were to objectively evaluate patient respiration and breathing change after contrast injection and to assess its potential impact on image quality for the hepatic arterial phase in gadoxetic acid-enhanced magnetic resonance imaging.This retrospective study was approved by the institutional review board, and the requirement for informed consent was waived. One hundred fifty-four patients underwent gadoxetic acid-enhanced liver magnetic resonance imaging with a 13-second breath-hold hepatic arterial phase. During the acquisition of precontrast and hepatic arterial phases, the respiratory motion signal was acquired and graded on a 4-point scale based on the SD of the respiratory waveform, with the highest grade indicating the worst breath-hold. Breath-holding grades 3 and 4 for the hepatic arterial phases were considered as breath-holding difficulty during the hepatic arterial phase. Gadoxetic acid-related dyspnea was defined as when the SD value of respiratory waveform during the hepatic arterial phase was 200 greater than that of the precontrast image. Then, the precontrast and hepatic arterial phase images were evaluated with respect to overall image quality and motion artifact using a 5-point scale, with the highest score indicating the worst image quality. In the hepatic arterial phase, the correlation between breath-holding degree and image quality parameters was evaluated using Pearson correlation. The differences in mean image quality scores between patients with and without gadoxetic acid-related dyspnea were evaluated using Student t test.Based on the analysis of the respiratory waveforms, the incidence of breath-holding difficulty during the hepatic arterial phase was 23.4% (33/154), and the incidence of gadoxetic acid-related dyspnea was 6.5% (10/154). By image analysis, the incidence of a degraded hepatic arterial phase (overall image quality score ≥4) was 5.2% (8/154). During the hepatic arterial phase, the breath-holding degree correlated with overall image quality and motion artifacts (r = 0.564 and 0.578, respectively). Patients with gadoxetic acid-related dyspnea showed significantly worse image qualities of the hepatic arterial phase than patients without gadoxetic acid-related dyspnea (all, P0.001), although image qualities for the precontrast image were not statistically significant between the 2 groups (all, P0.05).The objective analysis of respiratory patterns during a breath-hold is feasible and useful for evaluating gadoxetic acid-related dyspnea and its effect on image quality analysis.

The performance of alternating current driven electroluminescent devices significantly depends on the total amount of injected carriers as well as the balance of the number of injected carriers in an emission layer, which requires a careful design of the relative energy level structures of constituent layers. Here, we demonstrate a new field-induced hole generation layer between an emission layer and an insulator for high performance alternating current polymer electroluminescence (AC-PEL). Our hole generation layer of doped poly(3,4-ethylenedioxythiophene)–poly(styrene sulfonate) in the presence of multi-walled carbon nanotubes was also able to supply sufficient holes, giving rise to a good balance with the number of electrons readily injected from a top electrode. The resulting AC-PEL device exhibits high electroluminescence performance with a low turn-on root-mean-square voltage of 8.8 Vrms, a maximum luminance of 40 919 cd m−2, a maximum current efficiency of 3.74 cd A−1 and a power efficiency of 3.25 lm W−1. Other buffer layers such as WO3 and MoO3 are also suitable as field-induced hole generation layers. Moreover, our hole generation layer enables us to develop an extremely flexible and even foldable AC-PEL device when combined with a polymer insulator as well as a flexible transparent electrode based on the Ag nanowire network.