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IGZO/CsPbBr3-Nanoparticles/IGZO Neuromorphic Phototransistors and Their Optoelectronic Coupling Applications
No full textOptoelectronic synaptic devices are of great scientific and practical importance because of various potential applications such as ocular simulating and optical-electrical managers based on a new optoelectronic coupling mechanism. In this work, we design a novel channel layer with p-type CsPbBr3 nanoparticles (NPs) buried in an InGaZnO (IGZO) film to construct the corresponding thin-film transistors ( TFTs), which exhibits intense improvement in visible-light photosensitivity and synaptic plasticity as compared to the pure IGZO counterpart. Specifically, the composite device is able to exhibit versatile synaptic behavior under light stimuli with density as low as 0.12 mu W/cm(2) and with the gain 5-20 times higher than that of the IGZO TFT in the visible-light region. Based on the band alignment between the IGZO and NPs, the excitation and decay processes of intrinsic and photoinduced carriers are discussed. Moreover, owing to the gate bias control in a three-terminal configuration, our TFT synapses can imitate complex biological behaviors including the famous Pavlov's dog experiment and the reward and punishment mechanism of the brain via editing the gate voltage/light pulse stimuli
ICG and Sunitinib-loaded NH2-MOFs for Folate-mediated Hepatocellular Carcinoma Dual-modal Therapy
No full textThis research investigated a novel folic acid(FA)-modified zirconium core metal-organic framework(MOF) Uio-66 as a nanocarrier to deliver indocyanine green(ICG) and Sunitinib to cancer cells for combination therapy. Platinum-loaded Uio-66 nanoparticles(Pu) were synthesized via a one-pot method, followed by the modification with FA on their surfaces. This afforded FPu that enabled subsequent loading of ICG and Sunitinib to achieve dualmodal cancer therapy. Drug loading/release test and singlet oxygen detection were also conducted in vitro, and the nanoparticles showed considerable drug loading efficiency for both ICG and Sunitinib, coupled with a high singlet oxygen generation rate. Specifically, drug loading and encapsulation efficiency of Sunitinib were 2.30% and 72.67%, while those for ICG were 2.87% and 90.28%, respectively. Additionally, cytotoxicity test on HepG2 human hepatocellular carcinoma cancer cell line revealed that the fully functional nanoparticles possess excellent biocompatibility and as such could be further investigated as a potential drug delivery system for effectual carcinoma cancer treatment
Local Structures of Soft Carbon and Electrochemical Performance of Potassium-Ion Batteries
No full textDue to climate variation and global warming, utilization of renewable energy becomes increasingly imperative. Rechargeable potassium-ion batteries (PIBs) have lately attracted much attention due to their earth-abundance and cost-effectiveness. Because soft carbon materials are cheap, abundant, and safe, extensive feasible research studies have indicated that they could become promising anode materials for PIBs. In spite of gaining achievements, fundamental questions regarding effects of the basic structure unit inside soft carbon on potassium storage potential have not been sufficiently addressed yet. Here, a series of soft carbon pyrolyzed from 900 to 2900 degrees C were systematically and quantitatively characterized by combining Raman spectroscopy, near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, X-ray pair distribution function analysis, and advanced evaluation of wide-angle X-ray scattering data. All these characterizations reveal structural details of soft carbon with increasing pyrolysis temperature. Our results show that the potassium storage behavior, especially the potential plateau is closely correlated to non-uniformity in interlayer distance and defect concentration in soft carbon, which is further confirmed by reverse Monte Carlo (RMC) modeling and density functional theory calculation. On the basis of these results, optimizing strategies are discussed to design an advanced soft carbon anode. This work provides significant insights into the structure engineering of soft carbon for high-performance rechargeable PIBs
Facile Access to Uranium and Thorium Phosphaethynolate Complexes Supported by Tren: Experimental and Theoretical Study
No full textMain observation and conclusion The issue of covalence of actinide complexes remains controversial to date. The introduction of 2-phosphaethynolate anion into actinide complexes is expected to investigate the reaction mode and the bonding property. Herein, we describe the functionalization of An(Tren(TIPS))Cl (1: An = U; 2: An = Th) precursors with NaOCP(dioxane)(2.5) through salt-elimination method leading to the formation of the corresponding uranium and thorium phosphaethynolate species: [U(Tren(TIPS))(OCP)] (3) and [Th(Tren(TIPS))(OCP)] (4). These two complexes were fully characterized by nuclear magnetic resonance (NMR), FT-IR spectrum, UV-vis-NIR spectroscopies as well as X-ray crystal diffraction. Computational analyses of the two complexes reveal that the U-O bond has a more covalent bond property than the Th-O bond due to more 5f orbital contribution for U
Crystallization Control and Defect Passivation via a Cross-Linking Additive for High-Performance FAPbBr(3) Perovskite Solar Cells
No full textBromine-based hybrid perovskites exhibit excellent performance as the top layer of tandem cells, but their overall efficiency as single-junction devices is still very limited. In this work, trimethylolpropane ethoxylated triacrylate (TET), which can form a cross-linking polymer at the grain boundary after heating at 150 degrees C, is introduced as an additive in FAPbBr(3)-based perovskite solar cells. The FAPbBr(3) film with TET exhibits pinhole-free crystal grains with a large grain size. With a concentration of 5 mg/mL TET, the average grain size increases from 313 to 505 nm. What is more, Raman spectroscopy and X-ray photoelectron spectroscopy demonstrate that the cross-linked TET has a strong interaction with FAPbBr(3), which can passivate the defects of grain boundaries. Therefore, the FAPbBr(3)-based perovskite solar cells with TET achieve a power conversion efficiency of 8.93%. As we know, this is the highest value in FAPbBr(3)-based hybrid perovskites with an inverted planar structure. This work provides a new insight into the in situ cross-linking additive TET, which only exists at the grain boundary, does not enter the lattice, and has a crystallization control and defect passivation effect on FAPbBr(3) thin films, which will provide a new direction for further improving the performance of FAPbBr(3) perovskite solar cells
Resistive Switching Characteristics Improved by Visible-Light Irradiation in a Cs2AgBiBr6-Based Memory Device
No full textLight-modulated lead-free perovskites-based memristors, combining photoresponse and memory, are promising as multifunctional devices. In this work, lead-free double perovskite Cs2AgBiBr6 films with dense surfaces and uniform grains were prepared by the low-temperature sol-gel method on indium tin oxide (ITO) substrates. A memory device based on a lead-free double perovskite Cs2AgBiBr6 film, Pt/Cs2AgBiBr6/ITO/glass, presents obvious bipolar resistive switching behavior. The R-OFF/R-ON ratio under 445 nm wavelength light illumination is similar to 100 times greater than that in darkness. A long retention capability (>2400 s) and cycle-to-cycle consistency (>500 times) were observed in this device under light illumination. The resistive switching behavior is primarily attributed to the trap-controlled space-charge-limited current mechanism caused by bromine vacancies in the Cs2AgBiBr6 medium layer. Light modulates resistive states by regulating the condition of photo-generated carriers and changing the Schottky-like barrier of the Pt/Cs2AgBiBr6 interface under bias voltage sweeping
Leaf-derived sulfonated carbon dots: efficient and recoverable catalysts to synthesize 5-hydroxymethylfurfural from fructose
No full textSulfonated carbon dots (SCDs) were synthesized from plant leaves via continuously hydrothermal treatment by hydrogen peroxide and sulfuric acid, used as catalyst for converting fructose to 5hydroxymethylfurfural (HMF). Owing to nanosize effect and moderate acidic intensity, SCDs could thoroughly distribute in the solvent with an improved interfacial compatibility and selectively convert fructose to HMF. Under the optimal condition, the yield of HMF was 92.6% along with a fructose conversion of 100%, benefiting from a low activation energy of 52.9 kJ/mol when dimethylsulfoxide was used as solvent. The SCDs catalyst can be recovered, after six recycles, the fructose conversion and HMF yield were remained 66.1% and 56.2% under condition with incompletely conversion of fructose, respectively. This work provides a sustainable route to prepare carbon dots with a superior catalytic performance for converting biomass to important biobased platform chemicals. (c) 2021 Elsevier Ltd. All rights reserved
Zr2Al3C4 Coatings on Zirconium-alloy Substrates with Enhanced Adhesion and Diffusion Barriers by Al/Mo-C Interlayers
No full textZircaloy coating is one of the crucial technical ways to improve the accident tolerance of nuclear fuel cladding, which enables the zirconium-water reaction problems to be solved. Zr2Al3C4 coating is one type of candidate solutions to improve the high-temperature oxidation resistance of zirconium claddings. However, little study has been performed on the synthesis of Zr2Al3C4 coatings on zirconium alloy substrates due to the inter-diffusion, as well as the difference of the thermal expansion coefficients between the Zr2Al3C4 coating and the substrates. In this study, Zr2Al3C4 coatings were prepared through room-temperature magnetron sputtering and post annealing on zirconium alloy (ZIRLO) substrates with magnetron-sputtered Al/Mo-C interlayers. The effects of Al/Mo-C interlayers on phases and microstructures of Zr-Al-C coatings after annealing were studied by different methods. It is found that the coatings without interlayer are broken and no Zr2Al3C4 phase is formed due to significant interdiffusion between the Zr-Al-C coating and the substrate during annealing at 800 degrees C for 3 h. The Al/Mo-C interlayers prevented elemental diffusion between Zr-Al-C coatings and substrates during the post-annealing process. The Al/Mo-C interlayers act as diffusion barriers and greatly reduce the stoichiometric deviations from Zr2Al3C4 phase, which facilitates the formation of the Zr2Al3C4 phase in the final coating. Moreover, this diffusion-barrier layers contribute to eliminating cracks induced by the difference of the thermal expansion coefficients between the Zr2Al3C4 coatings and substrates. At the same time, the adhesions between Zr-Al-C coatings with Al/Mo-C interlayers and substrates were improved after annealing, with their strength exceeding 30 N
Ultrafast Carrier Dynamics of Amorphous Zinc Tin Oxide Graded Thin Films
No full textWe report the fabrication of amorphous zinc tin oxide (ZTO) thin films using rf magnetron sputtering and rapid postannealing. A vertically graded composition alloy (Zn1-xSnxO) is constructed in a single amorphous layer, which exhibits strong visible light absorption. The ultrafast carrier dynamics of the ternary zinc tin oxide film is investigated by femtosecond transient absorption (TA) spectroscopy, which shows that the photocarriers in ZTO films have nearly identical relaxation dynamics under an ultraviolet or visible pump, indicating that the visible light absorption is induced by band gap reduction rather than defect state in the ZTO film. Our results provide insights into understanding the photophysical mechanism of amorphous ZTO films and suggest that this gradient film is a promising candidate for solar cell and photodetector devices
Understanding the Effect of Sequential Deposition Processing for High-Efficient Organic Photovoltaics to Harvest Sunlight and Artificial Light
No full textAs the market of the Internet of Things (IoT) increases, great attention has been paid to the development of high-efficient organic photovoltaics (OPVs) utilizing artificial light. However, in a real indoor condition, the power density contribution of the artificial light cannot exceed 35% in the combination of indoor and outdoor irradiation, which indicates that the illumination of sunlight cannot be ignored during daytime. Hence, it is urgent to develop high-efficient OPVs in indoor conditions taking into account both sunlight and artificial light. In this work, a novel asymmetric molecule TB-4F was synthesized to trade-off the absorption spectrum that can be applied under both artificial light and sunlight. In conventional bulk-heterojunction (C-BHJ), it was figured out that due to nonoptimal morphology some carriers failed to be efficiently collected. Herein, a sequential deposition bulk-heterojunction (SD-BHJ) as an alternative fabrication method successfully enhanced the performance of OPVs, under both artificial light and sunlight, which was attributed to the favorable microstructure being vertically distributed in the active layer. Notably, the PCE was significantly increased by 25% for SD-BHJ compared to C-BHJ under artificial light, owing to the strong effect of trap-assisted recombination and dark current on PCE in the condition of low carrier density. Our result indicates that an asymmetric molecule with a blue-shifted spectrum fabricated by SD-BHJ can be a promising candidate that can be applied in indoor environments to harvest sunlight and artificial light simultaneously