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Flexible carbon nanofibers networks (FCNNs) play a crucial role in flexible and portable energy storage devices. Doping conductive and reactive N-atoms can enhance charge transport and transfer properties vital for high energy storage and high power. However, synchronous-ultrahigh conductive-reactive N-atoms doped FCNNs (SH-FCNNs) are still challenged by the N-atoms instability at high temperatures. To resolve this problem, an in-situ synergistic-carbonization-nitridation strategy is reported using polyaniline (PANI) implanted highly porous polyacrylonitrile nanofibers as a precursor. The obtained SH-FCNNs were doped with 5.9 at% conductive and 4.73 at% reactive N-atoms. They exhibit a superhigh specific capacitance (580.9 F g−1@0.5 A g−1) and high-rate capability (307.2 F g−1@128 A g−1). The flexible solid-state supercapacitors can output specific energy and power density of 18.3 Wh kg−1 and 16.9 kW kg−1. As for flexible solid-state Zn-ion batteries, the constructed SH-FCNNs@PANI cathodes have specific energy (290 Wh kg−1@0.159 kW kg−1) and supercapacitor-like power performance (128.1 Wh kg−1@23.3 kW kg−1). The synergistic effects of ultrahigh conductive and reactive N-atoms promote these performances to reach the mountaintop of flexible solid-state energy storage devices. The novel strategy also presents new insights on designing high-performance FCNNs for electrochemical energy storage, catalysts, and sensors.

With the recent progress in electronic skin, wearable medical devices and robotic systems, efforts have been devoted to capacitive proximity sensor and organic semiconductor proximity sensor. The former shows the proximity perception ability towards the conductor, and the latter enables proximity detection of the electrically charged objects. Here, by embedding rubrene organic semiconductor proximity sensor (insulator detector) and a parallel plate capacitive proximity sensor (metal detector) on the polydimethylsiloxane (PDMS) elastic substrate, we merge two-type proximity sensors in a single platform to realize a flexible, conformal composite proximity sensor, which enables good adherence onto the curved objects and detection of fingers, metal, and insulators, showing the strong application potential in wearable electronics.

Background Intrahepatic cholangiocarcinoma is an aggressive liver carcinoma with increasing incidence and mortality. A good auxiliary prognostic prediction tool is desperately needed for the development of treatment strategies. The purpose of this study was to explore the prognostic value of the radiomics nomogram based on enhanced CT in intrahepatic cholangiocarcinoma. Methods In this retrospective study, 101 patients with pathological confirmation of intrahepatic cholangiocarcinoma were recruited. A radiomics nomogram was developed by radiomics score and independent clinical risk factors selecting from multivariate Cox regression. All patients were stratified as high risk and low risk by a nomogram. Model performance and clinical usefulness were assessed by calibration curve, ROC curve, and survival curve. Results A total of 101patients (mean age, 58.2 years old; range 36–79 years old) were included in the study. The 1-year, 3-year, and 5-year overall survival rates were 49.5%, 26.6%, and 14.4%, respectively, with a median survival time of 12.2 months in the whole set. The least absolute shrinkage and selection operator (LASSO) method selected 3 features. Multivariate Cox analysis found three independent prognostic factors. The radiomics nomogram showed a significant prognosis value with overall survival. There was a significant difference in the 1-year and 3-year survival rates of stratified high-risk and low-risk patients in the whole set (30.4% vs. 56.4% and 13.0% vs. 30.6%, respectively, p = 0.018). Conclusions This radiomics nomogram has potential application value in the preoperative prognostic prediction of intrahepatic cholangiocarcinoma and may facilitate in clinical decision-making.

Organic-inorganic hybrid halide perovskites (OIHPs) with inherent mixed ionic-electronic conduction ability have been proposed as promising candidates for memristors with unique optoelectronic characteristics. Despite the great achievements toward understanding the working mechanism and exploring their functionality as water-sensitive materials, the humidity effect on the resistive switching (RS) characteristics still remains to be studied. This study investigates the humidity effect on the RS characteristics of Au/CH3NH3PbI3/FTO memristor. The memristor works well at moderate relative humidity (RH

Ion doping strategy is a promising method to enhance the efficiency of Cu2ZnSn(S,Se)4 (CZTSSe) solar cells, however, most of the reported works focus on studying the single ion doping in CZTSSe absorber layers. Here, Li+&Ag+ and Li+&Cd2+ double-ion-doping strategy are applied to improve the microstructure and device performances. We found that the double-ion-doping strategy can obviously increase the grain size, reduce the thickness of fine-grain layers and enhance the device performances. Furthermore, the PCEs of Li+&Ag+ and Li+&Cd2+ doped CZTSSe solar cells are up to 8.87% and 8.39%, respectively. It shows an encouraging improvement of over 43.5% and 35.8% enhancement compared with the traditional method (6.18%), and significantly higher than single ion doping strategy (7.60%, 7.99% and 7.11% for Li+, Ag+, and Cd2+ doped CZTSSe solar cells). This work provides a new solution to improve the microstructure and device performances of CZTSSe solar cells.

An insulating elastomer, as one of the indispensable components of skin-like electronic devices, significantly affects the mechanical and electrical properties of devices. However, the detailed inf...

In this letter, the dual buffer layers of AgInSbTe (AIST) and monolayer defective graphene (DG) are introduced into amorphous carbon (a-C)-based electrochemical metallization (ECM) type memristor. The advantages of promoting Ag dissolution and localizing cation diffusion region of AIST and DG layers can effectively suppress the well-known current overshoot issue and break the current-retention dilemma. Compared with its counterpart without buffer layer (Ag/a-C/Pt), the device with dual buffer layers (Ag/AIST/DG/a-C/Pt) presents excellent resistive switching (RS) performance, such as lower forming voltage with reduced overshoot current, smaller parameter fluctuations, and better cycling endurance. More importantly, the nonvolatile RS with low operation current of 10 $\mu \text{A}$ and remarkable endurance ( $> {3.1}\times {10}^{{7}}$ cycles) is realized, which is among the best of reported a-C-based ECM memories. Benefit from the low operation current, the device also shows the capacity of multilevel memory with six nonvolatile resistance states through regulating the compliance current.

Colloidal quantum dot solar cells (CQDSCs) are good candidates for low-cost power generators, due to their wide light-response range, high theoretical efficiency, and solution processability. Never...

PbS colloidal quantum dot solar cells (CQDSCs) employ ZnO electron transport layer have achieved high efficiency. However, there is nearly no efficient and batch production method to balance the charge separation and recombination within the device, which is one of the most obviously barrier to a satisfactory conversion efficiency. Here, a n+-n double-layered ZnO electron transport layer (DETL) is prepared by a facile one-step magnetron sputtering under different Ar pressure, and employed in heterojunction PbS colloidal quantum dot solar cells (CQDSCs) for the purpose of increasing charge separation at heterojunction interface via energy-band alignment modulation. The ZnO DETL, composed of a 100-nm-thick n+-ZnO bottom layer (n = 8 × 1019 cm−3) and a 20-nm-thick n-ZnO top layer (n = 3 × 1016 cm−3) significantly improve the power conversion efficiency (PCE) of the CQDSCs by a factor of ~35% compared to the device with single-layered n- ZnO. Open-circuit photovoltage decay (OCVD) measurements prove that the graded energy alignment of ZnO DETL effectively reduces both interfacial and trapping-assisted charge recombination, relative to the single-layered ZnO. The facile Ar-pressure tuning method makes the energy-band alignment process more convenient and sheds a light on the application of DETL electrons transport layer, fabricated by the universal technique of magnetron sputtering.

Inefficient charge injection and transport across the electrode/semiconductor contact edge severely limits the device performance of coplanar organic thin-film transistors (OTFTs). To date, various approaches have been implemented to address the adverse contact problems of coplanar OTFTs. However, these approaches mainly focused on reducing the injection resistance and failed to effectively lower the access resistance. Here, we demonstrate a facile strategy by utilizing the blurring effect during the deposition of metal electrodes, to significantly reduce the access resistance. We find that the transition region formed by the blurring behavior can continuously tune the molecular packing and thin-film growth of organic semiconductors across the contact edge, as well as provide continuously distributed gap states for carrier tunnelling. Based on this versatile strategy, the fabricated dinaphtho[2,3

Lead sulfide (PbS) colloidal quantum dot solar cells (CQDSCs) are emerging photovoltaic technology due to their outstanding light-harvesting ability in the visible and near-infrared spectral region, long-term air stability, multiple exciton generation and solution processability. However, PbS CQDSCs have been limited by the unsatisfactory carrier collection in the CQD films. Band alignment engineering using p-type hole transport layer (HTL) was proved to efficiently promote the carrier collection in cells with both planar and ordered bulky heterojunctional (OBH) structures. Nevertheless, seeking for proper p-type materials suitable for the PbS CQDSCs is still an open question. Herein, we reported a new p-type metal-organic material, CuSx, could act as HTL of PbS CQDSCs with OBH structure. The CuSx possesses a Fermi level EF (−5.02 eV), shallower valence band energy (−5.48 eV) and conduction band energy (−3.19 eV), inducing a proper band alignment at the PbS light-harvesting layer/CuSx interface. This not only enhanced hole extraction proved by the increase of short-circuit current density (Jsc) from 19.12 to 22.33 mA/cm2, but also blocked back electron demonstrated by the extended carrier lifetime. Consequently, cells with CuSx HTL generated a power conversion efficiency of 5.2%, leading to a PCE increase of 13% compared with that of reference HTL-free cell (4.6%). Our work introduced a promoting CuSx hole extraction material which shows great potential application in quantum-dot-based devices suffering from the insufficient carrier collection.

Flexibly manipulating optical and electrical properties of 2D materials is of great importance to extend their functional applications in the advanced optoelectronic field. Herein, a type II 2D/0D ...

In the past two decades, ZnO related materials and devices are widely used for various applications, such as thin-film transistors, photodetectors, light-emitting diodes, and transparent conductors because ZnO has several appealing features like abundant raw materials, environmental friendliness, wide and direct band gap, high electron mobility, and large exciton bonding energy. Especially, ZnO has been recognized as one of the most promising candidates for substituting commercial transparent conductors ITO which is exploited as transparent electrodes in solar cells and flat planar display and transparent heaters etc. For example, aluminum doped ZnO (AZO) transparent conducting films have been commercialized successfully. However, the figure of merits and stability of ZnO transparent conducting films still need to be further improved in order to meet the strict demands of practical large-scale applications. So far, various techniques have been developed to alleviate that contradiction between conductivity and visible light transmittance. In the past few years, a new strategy called anion and cation co-doping in ZnO has been widely implemented to improve the figure of merit, in which IIIA group elements are used as cation dopants and fluorine is used as anion dopants. It is worth noting that F has several advantages as anion dopant in ZnO. First, fluorine has a similar ionic radius with oxygen, which will avoid large lattice distortion. Second, the substitution for oxygen with fluorine only disturbs the valence band of ZnO and leaves the conduction band unaffected, which is beneficial for achieving high electron mobility. In this review, the latest researches of F and boron, or aluminum, or gallium, or indium co-doped ZnO thin films are summarized from both the theoretical and the experimental aspects. Effects of anion and cation co-doping on the optical and electrical properties and thermal stability of ZnO thin films are systematically discussed. Both theoretical and experimental results show that cation and anion co-doping can effectively improve the conductivity and visible light transmittance, no matter ZnO thin films were prepared by physical vapor deposition or synthesized by chemical solution processs. Taking Al and F co-doped ZnO (AFZO) thin films prepared with pulse laser deposition as an example, the mobility of AFZO thin film was apparently higher than that of Al-doped ZnO at the same carrier concentration. The high carrier mobility of AFZO is due to that the F can passivate the surface defects and acceptor-like complex defects in ZnO. In addition, the highly electronegative F makes the AFZO thin films exhibit excellent thermal stability, e.g. maintaining high conductive even after air-annealing at 600°C. These results indicate that anion and cation co-doping can effectively improve the performance of ZnO transparent conductive thin films and broaden their applications. Despite these exciting achievements, challenges still remain in the field of anion and cation co-doped ZnO thin films. For example, the mechanism of the co-doping strategy has not been clarified because the formation energy of intrinsic defects in ZnO is relatively low and the defects configurations for anion and cation co-doping are more complicated than single element doping case. Besides, we are still short of effective techniques and theoretical methods to reveal and simulate the behavior of defect clusters in co-doped ZnO. It is also urgent to establish the industrial standard of ceramic targets for co-doped ZnO to eliminate the discrepancies between different groups. More efforts should also be made in developing new equipment for large-scale manufacturing co-doped ZnO thin films. We hope this paper will provide reference to the readers who are interested in transparent conducting oxides.

By selecting the dielectrics that possess well-matched surface energy components with a semiconductor, the dinaphtho[2,3-b:2’,3’-f]thieno[3,2-b]thiophene (DNTT) single crystal FET with the mobility as high as 13 cm $^{{2}}\text{V}^{-{1}}\text{s}^{-{1}}$ is obtained. This high mobility combined with a pregrown single crystal as well as the good stability of DNTT provides an opportunity for fundamental studies of organic electronics. These results provide a general criterion for selection of dielectric self-assembled monolayers for an optimized carrier mobility in single-crystal organic filed-effect transistors, and show a promising method to simplify the dielectric optimization process for the development of next-generation high-performance flexible electronics.

Carrier-exciton interactions in two-dimensional transition metal dichalcogenides (TMDs) is one of the crucial elements for limiting the performance of their optoelectronic devices. Here, we have experimentally studied the carrier-exciton interactions in a monolayer MoS2-based two-terminal device. Such two-terminal device without a gate electrode is generally considered as invalid to modulate the carrier concentration in active materials, while the photoluminescence peak exhibits a red shift and decay with increasing applied voltages. Time-resolved photoluminescence spectroscopy and photoluminescence multipeak fittings verify that such changes of photoluminescence peaks result from enhanced carrier-exciton interactions with increasing electron concentration induce the charged exciton increasing. To characterize the level of the carrier-exciton interactions, a quantitative relationship between the Raman shift of out-of-plane mode and changes in electron concentration has been established using the mass action model. This work provides an appropriate supplement for understanding the carrier-exciton interactions in TMD-based two-terminal optoelectronic devices.

Kesterite Cu2ZnSn(S,Se)4 (CZTSSe) solar cells have drawn worldwide attention for their promising photovoltaics performance and earth-abundant element composition, yet the record efficiency of this type of device is still far lower than its theoretical conversion efficiency. Undesirable band alignment and severe non-radiative recombination at CZTSSe/CdS heterojunction interfaces are the major causes limiting the current/voltage output and overall device performance. Herein, we propose a novel two-step CdS deposition strategy to improve the quality of CZTSSe/CdS heterojunction interface and thereby improve the performance of CZTSSe solar cell. The two-step strategy includes firstly pre-deposits CdS thin layer on CZTSSe absorber layer by chemical bath deposition (CBD), followed with a mild heat treatment to facilitate element inter-diffusion, and secondly deposits an appropriate thickness of CdS layer by CBD to cover the whole surface of pre-deposited CdS and CZTSSe layers. The solar energy conversion efficiency of CZTSSe solar cells with two-step deposited CdS layer approaches to 8.76% (with an active area of about 0.19 cm2), which shows an encouraging improvement of over 87.98% or 30.16% compared to the devices with traditional CBD-deposited CdS layer without and with the mild annealing process, respectively. The performance enhancement by the two-step CdS deposition is attributed to the formation of more favorable band alignment at CZTSSe/CdS interface as well as the effective decrease in interfacial recombination paths on the basis of material and device characterizations. The two-step CdS deposition strategy is simple but effective, and should have large room to improve the quality of CZTSSe/CdS heterojunction interface and further lift up the conversion efficiency of CZTSSe solar cells.

Photochromic materials present photocontrollable properties, which is of great interest for potential applications including high-density storage and optical displays. Herein, we demonstrate a promising pathway toward smart photochromic nanocomposite exploration by anchoring of carbon dots (CDs) to titanium dioxide (TiO2) porous films. This study reveals that the color of the CDs/TiO2 film obtained by dropping anchoring becomes darker and that obtained by immersion anchoring becomes lighter, both under blue light irradiation. For the photobleaching material system, the spectral response is strongly dependent on wavelength and polarization of the exciting light, which provides new dimensions for optical information encryption and memory. This work lays the foundation for the materials platform in the integration of advanced information processing in the future.

Optoelectronic resistive switching (RS) devices are attracting attention due to their promising potential in optical communication technology. In this study, a photo-tunable organic memory device based on poly(4-vinylphenol) (PVP) and N-doped carbon quantum dot nanocomposites is presented. After UV light irradiation, the set voltage of the device can be gradually reduced by adjusting the irradiation time. This memory device presents excellent memory performance after large-angle bending or repetitive bending tests. More importantly, the controlled switching voltage characteristic enabled the realization of encrypted image storage. Raman spectra evidence that a local conductive sp2-hybridized carbon region was generated through UV light reduction, which can effectively enhance the internal electrical field and shorten the tunneling distance between the carbon dots, thus decreasing the set voltage. Our work provides a new approach towards the development of photo-tunable organic memory for future wearable optoelectronic neuromorphic computing systems.

Commercial applications of skin-like electronic devices for healthcare, intelligent robotics and electronic communication require large-scale high-density transistor arrays with high mechanical deformability and robustness that can be provided by intrinsically stretchable transistors. However, the contradictory crystallinity-dominated mobility and stretchability in the currently reported polymer semiconductors result in extremely limited high-mobility intrinsically stretchable transistors. Herein, based on a polymer with strong intrachain transport, we pioneer the use of molecular weight modulation to synchronously achieve increased mobility from 0.56 to 1.95 cm2 V−1 s−1 and increased crack-onset strain from 26 to 97% in the PIDTBT film. Based on the molecular weight modulation, a high-performance intrinsically stretchable transistor array with stretchability up to 100 percent strain and mobility up to 1.84 cm2 V−1 s−1, was demonstrated. Moreover, the stretchable transistor array presents a device density as high as 375 devices per square centimeter and good electrical performance at the static and dynamic stretching strain. Our results provide a new strategy for creating intrinsically stretchable transistors with high mobility and present unprecedented opportunities for large-scale high-density production of next-generation stretchable electronics.

Developing a conceptual “write”/“read” technology for optical information storage of persistent phosphors is necessary but often underestimated. Here we demonstrate a “write”/“read” approach of traps upon illumination by using a blue light-emitting diode (LED) in persistent phosphors such as LaMgGa11O19:Cr3+. Our investigation indicates that the phosphor can be charged upon high-power illumination (e.g., incident power density of 0.5 W cm−2) but discharged upon low-power illumination (e.g., 0.1 W cm−2). An appealing feature of the present approach is that the charging and discharging share the same illumination wavelength, which offers an interesting technical advantage and apparent convenience for applications. Moreover, such a manipulation technique is generally applicable for many existing phosphors.

As the most extensively used gas‐sensing devices, inorganic semiconductor chemiresistors are facing great challenges in realizing mechanical flexibility and room‐temperature gas detection for developing next‐generation wearable sensing devices. Herein, for the first time, flexible all‐inorganic yttria‐stabilized zirconia (YSZ)/In2O3/graphitic carbon nitride (g‐C3N4) (ZIC) gas sensor is designed by employing YSZ nanofibers as substrate, and ultrathin In2O3/g‐C3N4 heterostructures as active sensing layer. The YSZ substrate possesses small nanofiber diameter (310 nm), ultrafine grain size (23.9 nm), and abundant dangling bonds, endowing it with striking mechanical flexibility and strong adhesion with In2O3/g‐C3N4 sensing layer. Meanwhile, the ultrathin thickness (≈7 nm) of In2O3/g‐C3N4 ensures that the inorganic sensing layer has tiny linear strain along with the deformation of flexible YSZ substrate, thereby enabling unusual bending capacity. To address the operating temperature issue, the gas sensor is operated by using a visible‐light‐powered strategy. Under visible‐light illumination, the flexible ZIC sensor exhibits a perfectly reversible response/recovery dynamic process and ultralow detection limit of 50 ppb to toxic nitrogen dioxide at room temperature. This work not only provides an insight into the mechanical flexibility of inorganic materials, but also offers a valuable reference for developing other flexible inorganic‐semiconductor‐based room‐temperature gas sensors., A unique flexible all‐inorganic yttria‐stabilized zirconia (YSZ)/In2O3/graphitic carbon nitride (g‐C3N4) gas sensor is developed by employing YSZ nanofibers as substrate, and ultrathin In2O3/g‐C3N4 heterostructures as active sensing layer. Under visible‐light illumination, the flexible sensor exhibits perfectly reversible response/recovery dynamic process to toxic NO2 under extreme bending state at room temperature.

Broadband absorption is critical for the applications of metamaterial absorbers. In this work, a broadband long-wave infrared (LWIR) absorber with classical metal-dielectric-metal configuration is numerically demonstrated. The absorber consists of single-sized cut-wire arrays that show broadband and high extinction ratio, attributed to polarization-selective simultaneous excitation of propagated and localized surface plasmon resonances. The average absorption rate of the TM wave reaches 91.7% and 90% of the incident light is absorbed by the resonator in the wavelength range of 7.5–13.25µm so that the average extinction ratio in the resonator layer reaches 125. The polarization insensitive broadband absorption can be obtained by a cross resonator which can be treated as a pair of cut-wires perpendicular to each other. Our metamaterial absorber with single-sized resonators shows spatially concentrated broadband absorption and may have promising applications for hot-electron devices, infrared imaging, and thermal detection.

High-mobility polymer field-effect transistors (PFETs) are being actively explored for applications in soft electronic skin and low-cost flexible displays because of their superior solution processability, mechanical flexibility, and stretchability. However, most of high-mobility PFETs often deviate from the idealized behavior with variable mobility, large threshold voltage, and high off-state current, which masks their intrinsic properties and significantly impedes their practical applications. Here, it is first revealed that interface strain between polymer thin film and rigid substrate plays a crucial role in determining the ideality of PFETs, and demonstrate that various ideal conformable PFETs can be successfully fabricated by releasing strain. It is found that strain in film can be released by one-step peeling strategy, which can reduce π-π stacking distance and suppress generation of oxygen doped carriers, thereby obtaining linearly injected charge carriers and decreased carrier concentration in channel, eventually realizing ideal PFETs. More impressively, the fabricated ideal conformable PFET array displays outstanding conformability to curved objects, and meanwhile showing excellent organic light-emitting display driving capability. The work clarifies the effect of the interface strain on the device ideality, and strain can be effectively released by a facile peeling strategy, thus offering useful guidance for the construction of ideal conformable PFETs.

Light-emission phenomena of storage phosphors have received widespread attention, provoking the continuous developments of persistent luminescence, photostimulated luminescence, and mechanoluminescence. In the study and application of storage phosphors, as a matter of experience, it is always necessary to avoid or eliminate ambient light. It is the requirement for ambient darkness that is hindering the further development of storage phosphors under different ambient conditions. Here, we report an interesting glow phenomenon of storage phosphors in bright ambient light by introducing a concept termed ambient stimulated emission, in which the ambient temperature and ambient lighting can simultaneously release energy stored in the storage phosphors and lead to long-lasting emissions beyond the visible spectrum. As a proof of concept, we focus our discussion on an x-ray-charged ${\mathrm{La}\mathrm{Mg}\mathrm{Al}}_{11}{\mathrm{O}}_{19}:{\mathrm{Gd}}^{3+}$ phosphor, which exhibits ambient stimulated emission in the ultraviolet-B region, with increased initial light emission when the phosphor is exposed to ambient illumination instead of dark conditions. The ambient-stimulated-emission performances are found to depend on the illuminance and spectral distribution of ambient light. Moreover, our study indicates that the glow phenomenon in bright ambient light commonly appears in various storage phosphors, involving ultraviolet and infrared phosphors. The introduction of ambient stimulated emission brings different insights to luminescence research and offers approaches to further learn about and utilize storage phosphors.

Chemical surface treatment of colloidal quantum dots (CQDs) by phase-transfer ligand exchange (PTLE) is essential to implement highly densified, well-passivated CQD films for optoelectronic applications, such as infrared photovoltaics, light-emitting diodes and photodetectors. The PTLE, however, involves parallel and interactional processes of ligand exchange, phase transfer, and surface passivation of CQDs, which renders the optimization of PTLE still challenging. Herein, we explored the action mechanism of a widely-used additive, ammonium acetate (AA), on the PTLE of PbS CQDs in order to recognize the dynamic balance during the PTLE process and its impact on the performance of colloidal quantum dot solar cells (CQDSCs). Our research definitely shows that AA additive can modify the dynamics of PTLE by participating in all the three processes, and the amount of AA significantly influences the defect passivation and colloidal stability of PbS CQDs. At an appropriate concentration (~50 mM) of AA, PbS CQDs a...

The cause of hysteresis in organic field-effect transistors (OFETs) and its application in organic synaptic transistors are studied. Benefiting from the slow polarization process of dipoles in organosilicone (Dow Corning 1–2577) dielectric, the devices exhibit the desirable synaptic behaviors, including excitatory postsynaptic current (EPSC), memory function, potentiation/depression characteristics, endurance characteristics and spike-amplitude-dependent plasticity. Further, combining the DC 1–2577 dielectric with the polydimethylsiloxane (PDMS) support, a flexible conformable DC 1–2577 dielectric organic synapse transistor is fabricated, which provides a great potential for the wearable and implantable artificial neuromorphic systems for artificial intelligence and new-generation computers.

Highly conductive and transparent amorphous IZO films were fabricated by combining deep ultraviolet (DUV) excimer laser irradiation with solution combustion synthesis at low temperature. The influence of laser energy densities on the crystallinities, surface morphologies, and optical and electrical properties of the IZO films was investigated by using X-ray diffraction, scanning electron microscope, atomic force microscope, UV–vis spectroscopy, and Hall test. Additionally, Fourier-transform infrared spectroscopy showed that DUV laser irradiation led to the removal of organic residuals and hydroxyl groups. X-ray photoelectron spectroscopy showed that the percentage of metal‒oxide‒metal bonds in the IZO films increased significantly after the laser irradiation, which was beneficial for the electron transportation. As a result, the IZO films exhibited resistivity as low as 4.2 × 10−3 Ω cm with average visible transmittance as high as 91%, which yielded the highest Figure of Merit among the solution-processed transparent conducting films prepared at a temperature as low as 200 °C.

The development of short-wavelength light-emitting diodes (LEDs) with high emission efficiency, a fascinating research area, is still necessary because of great scientific interest and practical significance. Here, a graphene plasmon layer treated by oxygen plasma was employed into ZnO nanorod/p-GaN LEDs for a surface plasmon effect. The graphene-decorated heterojunction exhibited an approximately 4-fold improvement of ZnO ultraviolet (UV) electroluminescence (EL) intensity relative to a primitive p-n junction device. Time-resolved spectroscopy and temperature-dependent luminescence measurement indicated that the EL enhancement resulted from the coupling of ZnO excitons with graphene surface plasmons. The current research not only provides an opportunity to construct three-dimensional architecture from a vertical array of one-dimensional nanorods and a two-dimensional graphene layer, but also proposes an effective strategy to improve near-UV emission efficiency in various devices.

An ultrasensitive flexible organic sensor that uses the microsized rubrene crystal as the sensing element is demonstrated. The organic sensor with facile two-terminal device configuration can accurately perceive external charged objects, such as human hair, fiber cloth, plastic sheet, and paper scrap. The touch of these charged objects causes the effect of “gate” voltage of the traditional field-effect transistor, which modulates the carrier transport characteristics in the rubrene crystal. Benefiting from the unique sensing mechanism, the organic sensor is capable to resist the effect of gravity with high orientation stability. Our sensor shows a feasible route to realize the charged objects perception, making it a promising candidate for possible applications in artificial intelligence and human–machine interactive.

Gallium oxide (Ga2O3) has drawn great attention due to its potential application as a transparent conducting film. However, unavoidable oxygen vacancy (VO) induces the impurity level in the band gap, weakening the transparency of Ga2O3. On the other hand, the VO provides extra electron carriers, facilitating conductivity. Thus, coordinating the relation between the transparency and conductivity becomes rather urgent. Here, we propose that a co-dopant of aluminum (Al) and indium (In), together with oxygen vacancy (AlGa-InGa-VO), is a control method to eliminate the opaqueness and to simultaneously take advantage of the extra electron carriers resulting from the VO. First-principles electronic structure calculations reveal that AlGa with VO (AlGa-VO) does not eliminate the undesirable absorption of VO, whereas InGa-VO does. The defect formation energy of InGa-VO is higher than that of AlGa-VO. Intriguingly, AlGa-InGa-VO not only reduces the defect formation energy but also maintains the transparency of perfect Ga2O3. The strong hybridization between In 4d and O 2p induces the downshift of the impurity level, enhancing the optical bandgap. Our work indicates that doping equivalent elements might provide an effective way to achieve high transparent β-Ga2O3.

Stretchable conductors that can comfortably work even under extreme deformation, such as bending, twisting, folding, or stretching, are indispensable electronic components for constructing soft sen...

At present, the direct experimental observation and confirmation of thermal damage on semiconductors remain unexplored. This report presents clear evidence of the thermal irradiation damage on the electrode contact region of an organic semiconductor in the electrode deposition process by applying an ultralong uniform rubrene single crystal to simultaneously fabricate vacuum-deposited electrode and stamped electrode top-contact organic field-effect transistors (OFETs). The surface potential measurements combined with the transfer characteristics show that the thermal irradiation damage causes the HOMO level of rubrene shift downwards by 0.17 eV, resulting in the enhanced contact resistance and hence the lowered field-effect mobility. This interesting experimental discovery clarifies the nature of vacuum-deposited electrode induced thermal irradiation damage on OFETs, will enhance the understanding and development of contact engineering to further improve the performance of organic electronics.

In this work, novel 2D/0D hybrid heterostructures with facilely adjustable fluorescence intensity and carrier concentration are achieved by decorating monolayer MoS2 (1L-MoS2) flakes with semiconductor-dots (carbon-dots or ZnO-dots). By carbon-dot decoration, the fluorescence intensity of 1L-MoS2 is significantly suppressed due to the n-type doping effect of electron transfer from carbon-dots to 1L-MoS2. In contrast, 1L-MoS2 decorated with ZnO-dots exhibits remarkably enhanced photoluminescence, because of the effective p-type doping modulation of electron transfer from 1L-MoS2 to ZnO-dots. The different charge transfer directions lie in the distinct energy band alignment of the two heterostructures. Raman, time-resolved photoluminescence and X-ray photoelectron spectroscopy studies prove the effective charge transfer between 1L-MoS2 and carbon-dots/ZnO-dots. Semi-quantitative estimations based on a mass-action-model demonstrate that the electron concentration in 1L-MoS2 can be controllably tuned from 1012 to 1014 cm-2via the p-type/n-type doping effect of these hybrid heterostructures.

The nanostructuring of materials can solve the problem of low conductivity of the vanadate electrode, thereby increasing the potential for lithium storage performance. The traditional battery is prepared by coating active materials on current collector, which produces large contact resistance between the current collector and the electrodes, impeding the overall electrochemical performances of the battery. In this work, we propose and verify a scheme for directly loading porous iron vanadate nanowire array electrode on titanium foil. The resultant electrode (the as-prepared iron vanadate annealed at 300 °C) exhibits an enhanced lithium storage performance, the discharge capacity after 100 cycles is 1041.10 mAh·g−1 at a current density of 300 mA·g−1. The iron vanadate nanowire electrode is fabricated by a simple and scalable cation-exchange method, which can be provided for the separate and integrated large-scale industrialization of vanadate electrode materials.

Conformal organic thin-film transistors (OTFTs) that can adhere seamlessly to human skin or within the body are highly desirable for future large-scale low-cost wearable and implantable electronics. However, the fabrication of high-performance elastic dielectric-based conformal OTFTs is still a huge challenge, because it is difficult to directly deposit high-quality organic semiconductor thin films on elastic dielectrics. Here, a facile post-peeling modification approach is developed to functionalize the surface of elastic dielectrics and realize high-performance conformal OTFTs. The maximum hole and electron mobilities are respectively as high as 5.48 cm2 V−1 s−1 and 1.03 cm2 V−1 s−1, which are remarkably superior to all the reported values for elastic dielectric-based OTFTs. This functionalization approach significantly promotes the crystallinity and crystallite size of organic semiconductor thin films on elastic dielectrics, and paves the way for the fabrication of high-performance conformal and stretchable skin electronic devices.

Due to low-temperature processing properties and high carrier mobilities, solution-processed small molecule organic thin-film transistors (OTFTs) are promising candidates for enabling low-cost flexible electronic circuits and displays. Much progress has been made in terms of material performance, however, there remain significant concerns about well understanding and controlling the morphology and polymorphism of soluble small molecule organic semiconductor thin films. Here, we investigated the physical mechanisms of the dielectric interfacial properties on the recrystallization of soluble small molecule organic semiconductor thin films, and demonstrated an effective route to improve the thin-film morphology and device performance. We found that a low surface energy interface can derive low-temperature recrystallization behavior of solution-processed organic semiconductor thin films, which has an important impact on boosting the carrier mobility of OTFTs. After low-temperature recrystallization, the carrier mobility of OTFTs is dramatically enhanced by about one order of magnitude. These attractive results suggest that this work allows a better understanding about the role of dielectric interfacial properties in assisting the thin-film recrystallization towards the desirable thin-film morphology, indicating promising potential for future low-cost high-performance solution-processed organic electronic devices.

In this work, a new type of photoconductor with high responsivity and gain over a wide spectral range of DUV to NIR using a wide band gap amorphous gallium oxide (a-Ga2O3) thin film was reported for the first time. The responsivity (gain) at deep UV-250, UV-350, VIS-525 and NIR-850 nm is as high as 1099 (5438), 265 (936), 205 (483) and 122 A W−1 (178), respectively. More interestingly, we demonstrate that a novel “thermal relaxation” (TR) process (short-time heating) can effectively reduce the dark current and improve the response recovery time from hours to seconds without reducing the gain of the a-Ga2O3 detector. The mechanism related to oxygen vacancies and thermal energy and tail state excitation is proposed to explain our experimental phenomena. This result suggests that amorphous Ga2O3 films have potential applications in high-performance broadband photodetecting devices.

Herein, an effective and facile strategy was developed to construct a conformable artificial organ-damage memory system for sensing hazardous gas leakage by operating a single organic transistor at room temperature. The room-temperature gas sensing properties of organic semiconductors in the sustained adsorption and slow desorption endow the bionic device with the gas-controlled memristive effect. This facile electronic device geometry ensures accumulation of the sensing signal towards the single prolonged NO2 exposure and the long-term repeated NO2 exposure, allowing the system to simulate the inhalation, metabolism and cumulative organ damage of the human body upon hazardous gas leakage. Our study represents a step forward in simulating the human organ damage and exhibits the potential of the proposed system for future medical monitoring and non-invasive diagnosis in a portable and wearable sensing platform.

Sodium-ion batteries (SIBs) have become one of the most promising energy storage devices due to the high abundance and safety of sodium. On the other hand, most of the well-developed technologies in lithium-ion batteries (LIBs) can be migrated to SIBs. However, unfortunately, the known anode materials are not suitable in SIBs as a result of the larger atomic radius of sodium compared with lithium. Phosphorus demonstrates an unprecedented high theoretical capacity in SIBs, but its inherent low electrical conductivity and huge volume expansion upon sodiation greatly restrict the cycle stability. Two-dimensional materials as electrodes have shown unique advantages in contrast to their bulk counterparts. In this work, we identify a hitherto unknown P3C monolayer with a puckered honeycomb structure through first-principles swarm-intelligence structure calculations. More intriguingly, the predicted theoretical capacity of P3C as an anode for SIBs is up to 1022 mA g h−1, corresponding to a stoichiometry of P3CNa4. Metallic P3C and P3CNa4 can provide good electrical conductivity during the battery cycle. The acceptable barrier energy and lower open-circuit voltage ensure good rate capacity and safety in practical applications. Its outstanding performance is attributed to the unique arrangement of two kinds of hexagon rings (i.e. P6 and P4C2), producing high cohesive energy and thermodynamic stability. These desirable properties render P3C monolayers as a promising two-dimensional material for application in SIBs.

Herein, a novel photolithographic stretchable transparent hybrid electrode comprising spin-coated poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and a spray-coated single-wall carbon nanotube (SWCNT) network was prepared via one-step photolithography and all-dry etching. The PEDOT:PSS layer provided good interface wettability for the SWCNT aqueous dispersion to form an ultrathin uniform conductive film, which not only allowed the production of a photolithographic high-precision versatile electrode pattern, but also simultaneously ensured that the stretchable transparent electrode had the high optical transparency of up to 84% at 550 nm and good cyclic stretching stability. The photolithographic stretchable transparent electrodes, combined with a spin-coated dioctyl[1]benzothieno [3,2-b][1] benzothiophene (C8-BTBT) thin film and a mechanical lamination strategy, realized a photolithography-compatible all-solution-processed transparent conformal organic transistor array with the highest mobility of up to 2.7 cm2 V−1 s−1 and good operation stability in an LED driving circuit.

Hybrid organic–inorganic perovskite, CH3NH3PbI3 (MAPbI3), has attracted great attention as promising building blocks for resistive switching memory. However, the reproductive switching uniformity a...

Efficient light harvesting is essential for advanced photonic devices. Complex micro/nano surface relief structures can be produced via light-triggered mechanical movement, but limited in organic active molecular units. In this Letter, we propose to embed noble-metal particles into light-inactive polyvinyl alcohol matrix to construct a light harvesting system driven by plasmon for inscription of surface relief gratings. Ultra-small-sized silver nuclei are generated in the polymer by pre-thermal treatment, acting as an accelerator for the subsequent photoinduced particle growth, hydrogen group cleavage, and matrix softening. Based on such properties, a complex plasmonic array carrying ultra-high-density information is achieved with peristrophic multiplexing holography. This Letter paves a bright way to realize data storage, information encryption, and optical microcavity.

A neuromorphic computing chip that can imitate the human brain’s ability to process multiple types of data simultaneously could fundamentally innovate and improve the von-neumann computer architecture, which has been criticized. Memristive devices are among the best hardware units for building neuromorphic intelligence systems due to the fact that they operate at an inherent low voltage, use multi-bit storage, and are cost-effective to manufacture. However, as a passive device, the memristor cell needs external energy to operate, resulting in high power consumption and complicated circuit structure. Recently, an emerging self-powered memristive system, which mainly consists of a memristor and an electric nanogenerator, had the potential to perfectly solve the above problems. It has attracted great interest due to the advantages of its power-free operations. In this review, we give a systematic description of self-powered memristive systems from storage to neuromorphic computing. The review also proves a perspective on the application of artificial intelligence with the self-powered memristive system.

Broadband metamaterials absorbers with high absorption, ultrathin thickness and easy configurations are in great demand for many potential applications. In this paper, we first analyse the coupling resonances in a Ti/Ge/Ti three-layer absorber, which can realise broadband absorption from 8 to 12 μm. Then we experimentally demonstrate two types of absorbers based on the Ti/Ge/Si3N4/Ti configuration. By taking advantage of coupling surface plasmon resonances and intrinsic absorption of lossy material Si3N4, the average absorptions of two types of absorbers achieve almost 95% from 8 to 14 μm (experiment result: 78% from 6.5 to 13.5 μm). In order to expand the absorption bandwidth, we further propose two Ti/Si/SiO2/Ti absorbers which can absorb 92% and 87% of ultra-broadband light in the 14–30 μm and 8–30 μm spectral range, respectively. Our findings establish general and systematic strategies for guiding the design of metamaterial absorbers with excellent broadband absorption and pave the way for enhancing the optical performance in applications of infrared thermal emitters, imaging and photodetectors., Ultra-broadband metamaterials absorbers with high absorption, ultrathin thickness and easy configurations are designed and demonstrated, which pave the way for enhancing the optical performance in applications of infrared thermal emitters, imaging and photodetectors.

Purpose：The purpose of this study was to explore the correlation between CT texture features and the pathological grading of Pancreatic Neuroendocrine tumors. Materials and methods: A retrospective study was conducted on 54 patients (32 males and 22 females; average age (55.3 +11.1 years) with Pancreatic Neuroendocrine tumors (from March 2011 to May 2018) All patients had definite pathological diagnosis and grading results. The texture parameters of tumors were extracted from enhanced CT images taken before treatment. All parameters were analyzed by ROC curve, and the parameters with the largest AUC and P < 0.05 under each texture parameter category were selected. The selected parameters are modeled by binary logistic regression, and three models are constructed: image model, texture model and combined model. ROC was used to test the diagnostic capacity of these models. Result：We get the most discriminating image-based parameter (maxvalue, AUC: 0.678, p=0.037) and 5 most discriminating texture parameters (SHAPE_Volume (# vx), GLCM_Correlation, GLRLM_RLNU, NGLDM_Coarseness and GLZLM_ZLNU, AUC: 0.703,0.706, 0.715, 0.676, 0.702, p< 0.05) were selected by ROC analysis. Among them, maxvalue, SHAPE_Volume (# vx), GLCM_Correlation, GLRLM_RLNU and GLZLM_ZLNU tends to indicate pathological high-grade. NGLDM_Coarseness tends to indicate pathological low-grade. The AUC of image-based model is 0.678, with sensitivity of 81.1%, specificity of 52.9%. The AUC of texture model is 0.749, with sensitivity of 51.4%, specificity of 94.1%. The AUC of combined model is 0.766, with sensitivity of 56.8%, specificity of 94.1%. Conclusion: The preoperative enhanced CT image texture analysis to predict the pathological grade of pancreatic neuroendocrine tumors has a potential application.

Surface electron traps on semiconductor photoanodes mediate surface recombination and deteriorate the photoelectrochemical (PEC) water oxidation performance of the photoanode. Developing convenient methods to reduce surface electron traps is therefore essential for high efficiency PEC water oxidation on semiconductor photoanodes, particularly for nanostructured photoanodes with large surface area. Herein, we employ a O2 plasma treatment to boost the PEC water oxidation performance of Ti-doped Fe2O3 (Ti-Fe2O3) nanowires photoanodes, aiming to reduce surface oxygen vacancies, the dominant electron traps on Ti-Fe2O3 surface. X-ray diffraction (XRD), scanning electron microscopy and spectroscopic analyses show that the oxygen plasma treatment changes the structural, morphological and optical properties negligibly, but it does reduce the content of surface oxygen vacancies, as estimated from O1s X-ray photoelectron spectroscopy spectra. An optimal O2 plasma treatment (200 W, 70 s) increases the photocurrent density of the Ti-Fe2O3 nanowire photoanode to 2.14 mA·cm−2 (1.23 V vs. RHE) under air mass 1.5G simulated solar light, which is 1.95 times higher than the pristine Ti-Fe2O3 nanowire photoanode. The surface hole transfer efficiency is also improved by 1.66 times due to the reduced surface recombination. The work suggests that O2 plasma treatment is a convenient but effective method to boost the PEC water oxidation performance of Ti-Fe2O3 photoanode and might be applicable to other semiconducting oxide photoanodes for high efficiency PEC water splitting.

Contribution - The acquisition of analytical competencies is a desirable outcome of a technical graduate program. We present a process to align the program curriculum with an industry-standard to ensure those competencies. The result is not necessarily to create certified students (although that is certainly desirable) but to confirm that the program helps students acquire the analytical competencies as outlined in an industry standard. We describe a path for alignment of programs to develop these desirable competencies and our experience with the process. Background - We selected the INFORMS Certified Analytics Professional certification as a vendor-neutral book of knowledge and knowledge structure for analytics professionals and a well-developed credential in the profession. We used well-documented processes to align a university curriculum to industry needs, employed in aligning similar programs to such competencies as a project manager using the PMI PMP certification. Research questions - To align the curriculum to the INFORMS CAP, we asked: (1) whether students graduating from the program had acquired adequate analytical competencies; and (2) If they had not, how can the curriculum be modified to help gain those competencies. Methods - The curriculum was reviewed, and we assured initially that topical coverage of the pertinent course of study aligned adequately with the INFORMS CAP knowledge structure. Results - Using the existing curriculum, we found that a majority of the students could pass the INFORMS CAP certification practice exam at the end of their program of study. The exam results were sufficiently granular to modify the curriculum and course contents to improve future assessments’ passing rate.

Pressure/proximity sensing as the essential function of electronic skin (e-skin) has become an emerging technological goal for new-generation electronic devices in a wide variety of application fields, for example, smart electronics, human-machine interaction, and prosthetics. However, the current research lacks pressure/proximity detection of the stretched e-skin, which ignores the key elastic characteristic of skin and hinders the development of e-skin. Here, the pressure/proximity detection of the transparent e-skin in the stretching state is demonstrated based on poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS)/single-walled carbon nanotube (SWCNT). The high transparency of the e-skin realizes the visual imperception for wearable electronic systems. The perfect combination of stretchable SWCNT and highly conductive PEDOT:PSS endows the sensors with high stretchability and high discrimination capability toward strain, providing an effective way to overcome the interference of strain to realize accurate pressure/proximity detection of stretched e-skin at different strains.

An all-carbon memristive synapse is highly desirable for hardware implementation in future wearable neuromorphic computing systems. Graphene oxide (GO) can exhibit resistive switching (RS) and may be a feasible candidate to achieve this objective. However, the digital-type RS often occurring in GO-based memristors restricts the biorealistic emulation of synaptic functions. Here, an all-carbon memristive synapse with analog-type RS behavior was demonstrated through photoreduction of GO and N-doped carbon quantum dot (NCQD) nanocomposites. Ultraviolet light irradiation induced the local reduction of GO near the NCQDs, therefore forming multiple weak conductive filaments and demonstrating analog RS with a continuous conductance change. This analog RS enabled the close emulation of several essential synaptic plasticity behaviors; more importantly, the high linearity of the conductance change also facilitated the implementation of pattern recognition with high accuracy. Furthermore, the all-carbon memristive synapse can be transferred onto diverse substrates, showing good flexibility and 3D conformality. Memristive potentiation/depression was stably performed at 450 K, indicating the resistance of the synapse to high temperature. The photoreduction method provides a new path for the fabrication of all-carbon memristive synapses, which supports the development of wearable neuromorphic electronics. A graphene-based device can help computer chips behave more like human brains by transmitting current across thread-like wires. Neural synapses store memories by accessing different types of conductive states. Chinese researchers led by Haiyang Xu at Northeast Normal University in Changchun and Zhenhui Kang at Soochow University in Suzhou now demonstrate that graphene sheets with different conductivity levels—caused by adding or removing oxygen atoms—can also exhibit synapse-like behavior. The team developed a carbon-nitrogen composite to sandwich between two graphene electrodes with high and low levels of conductivity. Exposing the composite to ultraviolet light created numerous tiny filaments between the electrodes that physically restrict electron flow and provide gradual smooth transitions between the graphene electrodes’ two conductive states. The organic framework of this device also provides inherent flexibility for wearable devices. All-carbon memristive synapse is built through photo-reduction of a nanocomposite comprised of graphene oxide and N-doped carbon quantum dots. The analog-type resistive switching was demonstrated, which enabled the emulation of synaptic learning and pattern recognition with high accuracy. The all-carbon devices possess excellent transferability, flexibility and resistance to high temperature, showing the potential for the development of wearable neuromorphic computing system.

Metal nanowire networks (MNNs) are promising as transparent electrode materials for a diverse range of optoelectronic devices and also work as active materials for electrical heating and electromagnetic interference (EMI) shielding applications. However, the relatively low performance and poor durability of MNNs are limiting the practical application of the resulting devices. Here, we report a controllable approach to enhance the conductivity and the stability of MNNs with their transmittance remaining unchanged, in which reduced graphene oxide conformally wrapped silver nanowire networks (AgNW@rGO networks) are synthesized by selective electrodeposition of GO nanosheets on AgNWs followed by a pulsed laser irradiation treatment. Experimental characterizations and finite-difference time-domain simulations indicate that pulsed laser irradiation at a specific wavelength not only reduces the GO but also welds the AgNWs together through a surface plasmon resonance process. As a result, the AgNW@rGO networks exhibit low sheet resistance of 3.3 Ω/□, average transmittance of 91.1%, and good flexibility. Wrapping with rGO improves the maximum electrical heating temperature of the AgNW network transparent heaters due to the effective suppression of the oxidation and the migration of surface silver atoms. In addition, excellent EMI shielding effectiveness of up to 35.5 dB in the 8.2-12.4 GHz frequency range is obtained as a consequence of the combined effects of dual reflection, conduction loss, and multiple dielectric polarization relaxation processes.