Physical Properties of an Ultrathin Al2O3/HfO2 Composite Film by Atomic Layer Deposition and the Application in Thin-Film Transistors.

A high-quality ultrathin dielectric film is important in the field of microelectronics. We designed a composite structure composed of Al2O3/HfO2 with different Al2O3/HfO2 cycles prepared by atomic layer deposition (ALD) to obtain high-quality ultrathin (1-12 nm) dielectric films. Al2O3 protected HfO2 from interacting with the Si substrate and inhibited the crystallization of the HfO2 film. High permittivity material of HfO2 was adopted to guarantee the good insulating property of the composite film. We investigated the physical properties as well as the growth mode of the composite film and found that the film exhibited a layer growth mode. The water contact angle and grazing-incidence small-angle X-ray scattering analyses revealed that the film was formed physically at 3 nm, while the thickness of the electrically stable film was 10 nm from grazing-incidence wide-angle X-ray scattering and dielectric constant analyses. The composite film was applied as a dielectric layer in thin-film transistors (TFTs). The threshold voltage was decreased to 0.27 V compared to the organic field-effect transistor with the single HfO2 dielectric, and the subthreshold swing was as small as 0.05 V/dec with a carrier mobility of 49.2 cm2/V s. The off-current was as low as 10-11 A, and the on/off ratio was as high as 5.5 × 106. This ALD-prepared composite strategy provides a simple and practical way to obtain the high-quality dielectric film, which shows the potential application in the field of microelectronics.

Light-emitting field-effect transistors with EQE over 20% enabled by a dielectric-quantum dots-dielectric sandwich structure.

Emerging quantum dots (QDs) based light-emitting field-effect transistors (QLEFETs) could generate light emission with high color purity and provide facile route to tune optoelectronic properties at a low fabrication cost. Considerable efforts have been devoted to designing device structure and to understanding the underlying physics, yet the overall performance of QLEFETs remains low due to the charge/exciton loss at the interface and the large band offset of a QD layer with respect to the adjacent carrier transport layers. Here, we report highly efficient QLEFETs with an external quantum efficiency (EQE) of over 20% by employing a dielectric-QDs-dielectric (DQD) sandwich structure. Such DQD structure is used to control the carrier behavior by modulating energy band alignment, thus shifting the exciton recombination zone into the emissive layer. Also, enhanced radiative recombination is achieved by preventing the exciton loss due to presence of surface traps and the luminescence quenching induced by interfacial charge transfer. The DQD sandwiched design presents a new concept to improve the electroluminescence performance of QLEFETs, which can be transferred to other material systems and hence can facilitate exploitation of QDs in a new type of optoelectronic devices.

A painless and flexible bi-directional blood glucose-regulating system inspired by an inverter air conditioner.

Pursuing painless and flexible blood glucose regulation has been a century-long arduous mission. The current therapeutic systems can only regulate blood glucose unidirectionally (reduce), and the adjustment range is large, which is prone to the risk of hypoglycemia. Herein, inspired by the temperature fluctuation range controlled by the inverter air conditioner, we report a new bi-directional blood glucose-regulating drug delivery system (BDRS) consisting of glucose-loaded pressure-responsive nano-vesicles (Glu@PRNV), insulin-loaded black phosphorus nanosheets (Insulin@BPNs), hydrogel, and a painless blood sugar monitor patch. At first, BDRS could monitor blood glucose in real-time through visible color changes. Afterward, according to different requirements, BDRS could release glucose with the guidance of external pressure, or supplement insulin under near-infrared (NIR) irradiation, through which, the blood glucose level of diabetics could be accurately accommodated within a reasonable fluctuation range, thus minifying the likelihood of sudden hyperglycemia or hypoglycemia. Collectively, the supply-demand balance of blood glucose could be maintained via this real-time bi-directional drug delivery system, thereby improving the quality of life of diabetics. We have also verified the universality of this technique through a similar bi-directional sleep regulation.

Water-Soluble Doubly-Strapped Isolated Perylene Diimide Chromophore.

Perylene diimides (PDIs), a well-studied class of organic dyes, have a strong tendency to self-aggregate in water, thus greatly restricting their phototheranostic applications. Herein, we report a water-soluble PDI cyclophane "Gemini Box" (GBox-14+ ), consisting of a central PDI chromophore enclosed by double-sided cationic molecular straps. Owing to the effective spatial isolation, the chromophore self-aggregation can be completely eliminated, even in a concentrated aqueous solution up to 2 mM. To our knowledge, GBox-14+ represents an interesting example of a fluorescent PDI cyclophane in water, capable of being employed for lysosome-targetable live-cell imaging. More importantly, the highly concentrated aqueous solution of PDI radical anion can be significantly stabilized by GBox-14+ to exhibit an excellent near-infrared photothermal effect, which was further exploited for efficient and selective antibacterial applications. This work provides a new access to water-soluble non-aggregated organic dyes and promotes their potential biomedical applications.

Low-Temperature Fabrication of IZO Thin Film for Flexible Transistors.

Solution-processed thin film transistors (TFTs) used in flexible electronics require them to be fabricated under low temperature. Ultraviolet (UV) treatment is an effective method to transform the solution precursors into dense semiconductor films. In our work, high-quality indium zinc oxide (IZO) thin films were prepared from nitrate-based precursors after UV treatment at room temperature. After UV treatment, the structure of IZO thin films was gradually rearranged, resulting in good M-O-M network formation and bonds. TFTs using IZO as a channel layer were also fabricated on Si and Polyimide (PI) substrate. The field effect mobility, threshold voltage (Vth), and subthreshold swing (SS) for rigid and flexible IZO TFTs are 14.3 and 9.5 cm2/Vs, 1.1 and 1.7 V, and 0.13 and 0.15 V/dec., respectively. This low-temperature processed route will definitely contribute to flexible electronics fabrication.

Redox-responsive magnetic nanovectors self-assembled from amphiphilic polymer and iron oxide nanoparticles for a remotely targeted delivery of paclitaxel.

To reduce the side effect of paclitaxel and enhance accumulation at the tumor site, a novel redox-responsive nanovector with excellent biocompatibility based on disulfide-linked amphiphilic polymer and magnetic nanoparticle was prepared. The system would realize PTX release due to breakage of the disulfide bond when being targeted to the tumor site by the external magnetic field. The nanovector significantly improved endocytosis and enhanced accumulation at the tumor site, with an effective inhibition of tumor cells in vitro and in vivo.

Sequential Release Platform of Heparin and Urokinase with Dual Physical (NIR-II and Bubbles) Assistance for Deep Venous Thrombosis.

Disability and even death from acute thrombosis remain a grave menace to public health. At present, the traditional drugs represented by urokinase (UK) in clinical thrombolysis can cause side effects of bleeding when the dosage is excess. Therefore, a more effective and safer method of thrombolysis is urgently needed. In this paper, a multifunctional dual-drug sequential release thrombolysis platform (UK-UH@PDA@HMSNs) consisting of polydopamine (PDA)-modified hollow mesoporous silicon (HMSNs) loading with UK and unfractionated heparin (UH) was constructed with a double physical assistance (NIR-II and bubbles). With the aid of near infrared-II (NIR-II, 1064 nm, 1.0 W cm-2) laser, the photothermal effect of PDA could be motivated to facilitate the UH release, thereby accelerating the dissolution of thrombus. Afterward, the local hyperthermia effect could expedite the phase transition of l-menthol in HMSNs to generate bubbles to promote the release of UK, thereby realizing the sequential release of two thrombolytic drugs. Importantly, this method deftly conquered the inherent obstacle that UK and UH cannot be combined directly. In vivo and in vitro experiments proved that the thrombolytic efficiency of UK-UH@PDA@HMSNs stimulated by NIR-II was nearly 3 times than that of UK alone. Collectively, the proposed dual physical assistance and sequential dual-drug delivery system significantly improved the efficiency of thrombolysis under the premise of limiting drug doses; the risk of death from intracranial hemorrhage thus could be decreased radically.

Human hair derived uPA loaded capsules with dual near-infrared (I and II biowindows) laser responsive capabilities for multi-effective thrombolysis therapy.

Problems such as massive hemorrhage caused by uncontrolled drug dosage are the main significant obstacles in clinical thrombolytic therapy, which are prominently due to the lack of targeting and controlled release ability of efficient thrombolytic drug systems. In recent years, our team demonstrated that the photothermal effect can facilitate the thrombolytic effect of urokinase plasminogen activator (uPA). However, conventional photothermal agents are relatively expensive or contain heavy metals. If drug delivery systems with low toxicity, minimized heavy metal elements and easy accessibility (preferably provided by human self) can be developed, they will be of value in the future related applications. Herein, uPA-loaded human black hair derived nanoparticles with gelatin capsules (uPA@HBHNP@GNCs) were applied for the first time as a thrombolytic system. Upon irradiation by near-infrared I window (NIR-I) laser or II window (NIR-II) laser, the photothermal effect of HBHNP was triggered to promote the melting of the gelatin encapsulated around the outer layer, thereby realizing the targeted release of uPA. The in vitro and in vivo experiments demonstrated that the deep response to NIR (especially II window) of this system exhibited a satisfactory thrombolytic effect with ideal biosafety. Briefly, the proposed hair derived drug delivery system has the characteristics of human source, low cost, minimum heavy metal components, deep response to NIR (II window) laser, and good biocompatibility, which is expected to be expanded to the treatment for some diseases, even in deep tissue areas.

Hyperthermia-triggered UK release nanovectors for deep venous thrombosis therapy.

Deep vein thrombosis (DVT) is a common and lethal complication of surgery. In the clinic, thrombolytic drugs are primarily used for treating DVT. However, the utilization of thrombolytic drugs is limited due to the risk of urokinase (UK)-related hemorrhagic complications. In this paper, a binary eutectic phase-change fatty acid composed of lauric acid and stearic acid was used to block the pores of gold-mesoporous silica core-shell nanoparticles, so as to deliver thrombolytic drugs. The eutectic mixture has a well-defined melting point at 39.2 °C, which can be used as a biocompatible phase-change material for hyperthermia-triggered drug release. The prepared system presents remarkable photothermal effects due to the gold nanoparticles and quick drug release in response to near-infrared irradiation (NIR). In addition, localized hyperthermia could also enhance the lysis of the thrombus. The thrombolytic effect of this system was evaluated in vitro and in vivo. Herein, a rabbit femoral vein thrombosis model was first built for imitating thrombolysis in vivo. The B-ultrasound was then used to monitor the changes in the thrombus after treatment. The results indicated that the reported system could be potentially used to deliver thrombotic drugs in the clinic.

Shear-, Sound-, and Light-Sensitive Nanoparticles for Thrombolytic Drug Delivery.

Thrombotic diseases, as potentially induced by blood clots or vascular embolization, frequently occur with high rates of mortalities worldwide. Current drug thrombolysis, a primary clinical therapy, may increase fatal risk of hemorrhage when thrombolysis agents become systemically distributed. Given current thrombolysis limitations, some novel drug delivery systems based on nanoparticles have been recently exploited to achieve a more controlled release of loaded thrombolytic agents, able to respond to environmental changes, and resulting in a safer thrombolysis. In this review, the authors outline and discuss some prominent examples of early and recent thrombolytic agent delivery systems using controlled release by physical stimuli (shear, sound and light). Shear-sensitive systems are designed to exploit the specific biomechanical feature of thrombosis, that is, the increased blood shear stress. Sound- and light-sensitive systems reflect "remote control" of drug release by responding to external ultrasound or light stimulus. These smart thrombolytic drug delivery systems hold promise for more effective and safer future thrombolytic therapy.

Titanium silicalite as a radical-redox mediator for high-energy-density lithium-sulfur batteries.

Lithium-sulfur (Li-S) batteries are receiving intense interest owing to their high energy densities, cost effectiveness, and the natural abundance of sulfur. However, practical applications are still limited by rapid capacity decay caused by multielectron redox reactions and complex phase transformations. Here, we include commercially available titanium silicalite-1 (TS-1) in carbon/sulfur cathodes, to introduce strong chemical interactions between the lithium polysulfides (LiPS) and TS-1 in a working Li-S battery. In situ UV-visible spectroscopy together with other experimental results confirm that incorporation of TS-1 mediators enables direct conversion between S82- and S3*- radicals during the discharge process, which effectively promotes the kinetic behaviors of soluble LiPS and regulates uniform nucleation and growth of solid sulfide precipitates. These features give our TS-1 engineered sulfur cathode an ultrahigh initial capacity of 1459 mA h g-1 at 0.1C. Moreover, the system has an impressively high areal capacity (3.84 mA h cm-2) and long cycling stability with a high sulfur loading of 4.9 mg cm-2. This novel and low-cost fabrication procedure is readily scalable and provides a promising avenue for potential industrial applications.

A magnetically modified black phosphorus nanosheet-based heparin delivery platform for preventing DVT accurately.

A new heparin targeting delivery platform was developed based on iron oxide (Fe3O4) nanoparticles and polyethyleneimine (PEI) functionalized black phosphorus nanosheets (BP NSs). Both in and ex vivo studies suggested that this drug delivery platform (PEI/Fe3O4@BP NSs) possessed high heparin loading capacity (≈450%), accurate magnetic enrichment capacity, and good biocompatibility. With the aid of near-infrared (NIR) laser irradiation, this BP NS based delivery platform could further enhance the photothermal thrombolysis effect. Most importantly, the experiments in vivo confirmed that the proposed PEI/Fe3O4@BP NSs could considerably prolong the effective drug concentration duration of heparin. By which means, accurate, long-acting, and effective thromboprophylaxis could be accomplished with limited drug dosage, which could radically reduce the perniciousness of drug overdose.

Several biological benefits of the low color temperature light-emitting diodes based normal indoor lighting source.

Currently, light pollution has become a nonnegligible issue in our daily life. Artificial light sources with high color temperature were deem to be the major pollution source, which could induce several adverse effects on human's health. In our previous research, we have firstly developed an artificial indoor light with low color temperature (1900 K). However, the biological effects of this artificial light on human's health are unclear. Here, four artificial lights (1900 K, 3000 K, 4000 K and 6600 K) were used to evaluate some biological changes in both human (in total 152 person-times) and murine models. Compared with other three high color temperature artificial lights, our lights (1900 K) presented a positive effect on promoting the secreting of melatonin and glutamate, protecting human's eyes, accelerating would healing and hair regeneration. These systematical studies indicated that the proposed low color temperature (1900 K) light could provide several significant benefits in human's daily life.

Surface nano-engineered wheat straw for portable and adjustable water purification.

Wheat straw (WS), as a cheap and abundant agricultural waste, is usually burned directly in farmland and causes severe air pollution. Therefore, biochar derived from waste WS is prepared and modified by nanoscaled zinc oxide through a facile in-situ surface-modification process. For ease of use, a 3D printed finger-sized unit (FSU) loaded with the above as-prepared WS is designed and implemented. Each unit weighs only 4 g, and could simultaneously reduce three major water contaminants: bacteria, organic dyes, and heavy metal ions. Moreover, it is interesting to note that fresh wheat straw is a flexible material and has excellent electrical conductivity after carbonization. These two properties (flexibility and conductivity) could further adjust water purification performance. The subsequent cellular and animal tests confirmed the biosafety of the water purified with FSU alone.

Localized Light-Au-Hyperthermia Treatment for Precise, Rapid, and Drug-Free Blood Clot Lysis.

Thrombus diseases, induced by blood stasis or vascular embolization normally, frequently occur with high disability and mortalities worldwide. At present, drug thrombolysis, a primary clinical therapy for blood clot lysis, could increase the lethal risk for hemorrhage when thrombolysis agents are overused in the whole body. Therefore, a novel and advanced therapy for blood clot lysis, based on remote physical signals, is helpful for assisting clinical therapy. Here, we used the localized light-Au-hyperthermia (LAH) treatment, induced by gold nanorods (Au NRs) irradiated with near-infrared light (808 nm), for precise, rapid, and drug-free blood clot lysis. The LAH technology was first introduced in the murine hematoma model and the murine myocardial infarction model for blood clot lysis. Compared with traditional therapy, LAH was assured to shorten the time of detumescence in the murine hematoma model owing to their precise and localized hyperthermia. Meanwhile, we also discovered that LAH was a benefit to vascular recanalization in the murine myocardial infarction model. In addition, the Au NRs used in LAH present ideal biocompatibility in the murine model, which endows it to be suitable for blood clot lysis in vivo.

Enhanced photovoltaic performance of inverted polymer solar cells through atomic layer deposited Al2O3 passivation of ZnO-nanoparticle buffer layer.

In this work, an atomic layer deposited (ALD) Al2O3 ultrathin layer was introduced to passivate the ZnO-nanoparticle (NP) buffer layer of inverted polymer solar cells (PSCs) based on P3HT:PCBM. The surface morphology of the ZnO-NP/Al2O3 interface was systematically analyzed by using a variety of tools, in particular transmission electron microscopy (TEM), evidencing a conformal ALD-Al2O3 deposition. The thickness of the Al2O3 layers was optimized at the nanoscale to boost electron transport of the ZnO-NP layer, which can be attributed to the suppression of oxygen vacancy defects in ZnO-NPs confirmed by photoluminescence measurement. The optimal inverted PSCs passivated by ALD-Al2O3 exhibited an ∼22% higher power conversion efficiency than the control devices with a pristine ZnO-NP buffer layer. The employment of the ALD-Al2O3 passivation layer with precisely controlled thickness provides a promising approach to develop high efficiency PSCs with novel polymer materials.

Silver nanowire net knitted anisotropic aerogel as an ultralight and sensitive physiological activity monitor.

Inherent highly ordered anisotropic aerogels were prepared through a facile celery-carbonization process. The subsequent modification of silver nanowire knitted nets endowed the prepared carbonaceous aerogel with several valuable properties, including broad-spectrum antibacterial activity, near-infrared responsive heating, lightweight cushioning and anisotropic pressure-sensitive conductivity. With the aid of 3D printing technology, this versatile material could be applied as an ultralight monitor to realize the visualized detection of different physiological activities, such as ankle movements and cardiac arrhythmias.

Three-dimensional sp2 carbon networks prepared by ultrahigh temperature treatment for ultrafast lithium-sulfur batteries.

The current challenge in the development of high-performance lithium-sulfur (Li-S) batteries is to facilitate the redox kinetics of sulfur species as well as to suppress the shuttle effect of polysulfides, especially at high current rates. Herein, aiming the application of Li-S at high current rates, we coupled a sp2 carbon configuration consisting of 3D carbon nanotubes/graphene prepared by ultrahigh temperature treatment (2850 °C) with S (2850CNTs-Gra-S) for application in Li-S batteries. The 2850CNTs-Gra as the host material exhibits a nearly perfect sp2 hybridized structure because ultrahigh temperature treatment not only repairs the raw defects in CNTs and graphene, but it also forms new sp2 C-C bonds between them. The 3D sp2 carbon network ensures ultrafast ion/electron transfer and efficient heat dissipation to protect the integrity of the separator when the Li-S battery is running at an ultrahigh rate. Based on these unique advantages, the 2850CNTs-Gra-S cathode shows a high current rate performance. Critically, it still delivers a considerable specific capacity after 1500 cycles even at a current rate of 15C and exhibits an extremely low capacity degradation rate of 0.0087% per cycle.

Platelet-Mimic uPA Delivery Nanovectors Based on Au Rods for Thrombus Targeting and Treatment.

Systemic thrombolytic drug administration has always gained an unideal therapeutic effect due to the rapid neutralization by its antidotes. It is significant to seek an approach for targeted thrombolytic drug delivery to the thrombus. Here a biocompatible, thrombus-targeted, and low-cost platelet-mimic nanovector was fabricated to accomplish a sustained urokinase plasminogen activator (uPA) release at the thrombus site. The prepared system presented a sustained model drug release behavior for 30 h and burst release behavior under near-infrared laser irradiation with hyperthermia in vitro. We demonstrate that the fabricated nanovectors can arrive and aggregate at the pulmonary thrombus, followed by a sustained uPA release in the murine pulmonary embolism model. Therefore, according to the results, the formulated nanovector presented a hopeful application for targeted thrombolytic therapy clinically.

"Less Blue, More Clean": Cu2O nano-cubic functionalized hydrogel for the energy transformation of light-emitting screens.

Cubic Cu2O nanoparticle modified hydrogel (CMHG) was synthesized to address two major problems (harmful irradiation and high density pathogens) of the current light-emitting screens simultaneously. The as-prepared hydrogel could conveniently form an adjustable semitransparent film over various shaped screens to provide enhanced antibacterial activity and longer Cu2O service life. More importantly, with the aid of cubic Cu2O nanoparticles, the energy of the harmful blue light irradiation could be effectively transformed into a photocatalysed power source to sterilize the surface of the screen. This low toxic CMHG showed no significant influence on the touch control experience, and had obvious eye protective effects, which thus offered a convenient manner to protect vision and sterilize touch screens at the same time.