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Sintered agglomerate of synthetic mesoporous silica nanoparticles (MSNs) is an architected geomaterial that provides confinement-mediated flow and transport properties of fluids needed for environmental research such as geological subsurface energy storage or carbon capture. The design of those properties can be guided by numerical simulations but is hindered by the lack of method to characterize the permeable pores within MSNs due to pore size. This work uses the advances of an Individual Particle cryogenic transmission Electron Tomography (IPET) technique to obtain detailed 3D morphology of monodispersed MSNs with diameters below 50 nm. The 3D reconstructed density-maps show the diameters of those MSNs vary from 35-46 nm, containing connected intraparticle pores in diameter of 2-20 nm with a mean of 9.2 ± 3 nm, which is comparable to the mean interparticle pore diameters in sintered agglomerate. The characterization of the pore shape and dimensions provides key information for estimating the flow and transport properties of fluids within the sintered agglomerate of those MSNs and for modeling the atomic MSN structures needed for pore-fluid simulations.

Organic field‐effect transistors (OFETs) hold great promise for applications in non‐volatile memories, detectors, and artificial synapses due to the good flexibility and biocompatibility. However, certain drawbacks such as high operating voltages and significant degradation in endurance characteristics have hindered their practical implementations. Herein, a novel approach is proposed to enhance the performance of OFETs by incorporating a bi‐functional n‐type polymer semiconductor interlayer, Poly‐{[N,N'‐bis(2‐octyldodecyl)naphthalene‐1,4,5,8‐bis(dicarboximide)‐2,6‐diyl]‐alt‐5,5′‐(2,2′‐bithiophene)} (N2200), into a pentacene OFET structure. The device exhibits remarkable improvements, with reliable P/E operation cycles of over than 104 and a retention time of more than 10 years. On one hand, the inclusion of N2200 as an n‐type semiconductor effectively reduces the height of hole‐injection barrier for trapping and thus reducing the working voltage based on the electrostatic induction theory. On the other hand, n‐type semiconductor N2200 serves as a native hole‐consumption (or hole‐trapping) dielectric, and its narrower bandgap restrains the formation of deep hole‐traps, thus favoring the endurance characteristics of the OFET. [ABSTRACT FROM AUTHOR]

The synapse is one of the fundamental elements in human brain performing functions such as learning, memorizing, and visual processing. The implementation of synaptic devices to realize neuromorphic computing and sensing tasks is a key step to artificial intelligence, which, however, has been bottlenecked by the complex circuitry and device integration. We report a high-performance charge-trapping memory synaptic device based on two-dimensional (2D) MoS2 and high-k Ta2O5–TiO2 (TTO) composite to build efficient and reliable neuromorphic system, which can be modulated by both electrical and optical stimuli. Significant and essential synaptic behaviors including short-term plasticity, long-term potentiation, and long-term depression have been emulated. Such excellent synaptic behaviors originated from the good nonvolatile memory performance due to the high density of defect states in the engineered TTO composite. The 2D synaptic device also exhibits effective switching by incident light tuning, which further enables pattern recognition with accuracy rate reaching 100%. Such experimental demonstration paves a robust way toward a multitask neuromorphic system and opens up potential applications in future artificial intelligence and sensing technology.

Abstract The structural and optical characterizations of titania incorporated with alumina nanocrystals have been presented in this paper and the films exhibit excellent properties like low current density, small hysteresis as well as high photoluminescence quantum yields of about 361 nm. These properties are promising for the applications in future electronic devices.

The synapse is one of the fundamental elements in human brain performing functions such as learning, memorizing, and visual processing. The implementation of synaptic devices to realize neuromorphic computing and sensing tasks is a key step to artificial intelligence, which, however, has been bottlenecked by the complex circuitry and device integration. We report a high-performance charge-trapping memory synaptic device based on two-dimensional (2D) MoS2 and high-k Ta2O5–TiO2 (TTO) composite to build efficient and reliable neuromorphic system, which can be modulated by both electrical and optical stimuli. Significant and essential synaptic behaviors including short-term plasticity, long-term potentiation, and long-term depression have been emulated. Such excellent synaptic behaviors originated from the good nonvolatile memory performance due to the high density of defect states in the engineered TTO composite. The 2D synaptic device also exhibits effective switching by incident light tuning, which further enables pattern recognition with accuracy rate reaching 100%. Such experimental demonstration paves a robust way toward a multitask neuromorphic system and opens up potential applications in future artificial intelligence and sensing technology. [ABSTRACT FROM AUTHOR]

Lead-free (1 − x)(0.8Bi0.5Na0.5TiO3-0.2SrTiO3)-xLiNbO3 (BNST-xLN, x = 0-0.08) piezoelectric ceramics were fabricated by a solid-state sintered technology. The effects of LN-doping on the structural and electrical properties of the BNST-xLN system were systematically investigated. The results of Raman spectroscopy revealed that the substitution of LN softens the phonon vibrations in the BNST-xLN system, in accordance with the remarkable reduction in the phase transition temperature (TF−R), remnant polarization (Pr), negative strain (Sneg) and piezoelectric coefficient (d33). However, the degradation of the long-range ferroelectric orders was accompanied by a significant increase in the electric field-induced strain response. At x = 0.04, a maximum unipolar strain of ~ 0.36% with a corresponding normalized strain (Smax/Emax) of ~ 600 pm/V was obtained at room temperature, which should be mainly ascribed to the reversibly electric field-induced phase transition between the ergodic relaxor and ferroelectric phases due to their comparable free energies in the two-phase coexistence region. Moreover, it was also found that the BNST-xLN system processes predominant electrostrictive behaviors with relatively high electrostrictive coefficient (Q33) and excellent temperature stability when the field-induced phase transition cannot be trigged by the applied electric field, as evidenced by a fact that the Q33 value of BNST-0.08LN ceramic keeps almost constant as high as ~ 0.028 m4/C2 in the temperature range from room temperature to 120 °C. [ABSTRACT FROM AUTHOR]

Lead-free 0.985[(0.94− x)Bi0.5Na0.5TiO3-0.06BaTiO3- xSrTiO3]-0.015LiNbO3 [( BNT- BT- xST)- LN, x=0-0.05] piezoelectric ceramics were prepared using a conventional solid-state reaction method. It was found that the long-range ferroelectric order in the unmodified ( BNT- BT)- LN ceramic was disrupted and transformed into the ergodic relaxor phase with the ST substitution, which was well demonstrated by the dramatic decrease in remnant polarization ( Pr), coercive field ( Ec), negative strain ( Sneg) and piezoelectric coefficient ( d33). However, the degradation of the ferroelectric and piezoelectric properties was accompanied by a significant increase in the usable strain response. The critical composition ( BNT- BT-0.03 ST)- LN exhibited a maximum unipolar strain of ~0.44% and corresponding normalized strain, Smax/ Emax of ~880 pm/V under a moderate field of 50 kV/cm at room temperature. This giant strain was associated with the coexistence of the ferroelectric and ergodic relaxor phases, which should be mainly attributed to the reversible electric-field-induced transition between the ergodic relaxor and ferroelectric phases. Furthermore, the large field-induced strain showed relatively good temperature stability; the Smax/ Emax was as high as ~490 pm/V even at 120°C. These findings indicated that the ( BNT- BT- xST)- LN system would be a suitable environmental-friendly candidate for actuator applications. [ABSTRACT FROM AUTHOR]

In this work, we have fabricated and thoroughly characterized dielectric-stacked memory devices with AlO-CuO composites as the charge trapping layer which are prepared by using atomic layer deposition and RF-magnetron sputtering techniques. The devices exhibit a large memory window of 13.27 V and a density of the trapped charges of 9.37 × 10 cm at a working voltage of ±11 V. The microstructural observations by using high resolution transmission electron microscopy and the analysis on X-ray photoelectron spectroscopy indicate that the strong charge-trapping ability of AlO-CuO composite should be ascribed to the occurrence of Cu, resulted by the inter-diffusion at the interface of CuO/AlO. Such an interesting composite layer has very attractive application in nonvolatile memory. [ABSTRACT FROM AUTHOR]