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Various 2D materials have received considerable attention as emerging nanoscale materials for low‐power and high‐performance electronic and optoelectronic device applications. Among these, layered double hydroxide (LDH)‐based nanocomposites are promising materials because of their structural diversity and electronic functionality, which are suitable for photocatalysts, catalytic supports, and charge storage. Here, three Al‐based LDHs using different divalent cations (Zn2+, Ni2+, and Co2+) are synthesized, and their electrical characteristics are investigated in the form of a two‐terminal Pt/Al‐based LDHs/fluorine‐doped tin oxide junction structure. Only the ZnAl‐LDH junction exhibits a distinct unipolar switching behavior with an ON–OFF ratio of ≈103 and transmittance of ≈87%; the other junctions (NiAl‐ and CoAl‐LDHs) do not exhibit switching and possess relatively low transparency. This difference is attributed to the relatively vertically stacked ZnAl‐LDH layer, which enables the formation of a switching filament through the vertical 2D layer and enhances transparency. The ZnAl‐LDH junction has a relatively low trap energy (Et) of ≈0.1 eV that can decrease the SET voltage as the temperature increases, which can be understood by trap‐assisted space‐charge‐limited conduction with thermal‐assisted electron excitation. This study sheds light on the potential use of transparent and self‐organized vertical stacked ZnAl‐LDH materials as resistive switching devices. [ABSTRACT FROM AUTHOR]

A series of small molecules that contained identical π-spacers (ethyne), a central diketopyrrolopyrrole (DPP) unit, and different aromatic electron-donating end-groups were synthesized and used in organic solar cells (OSCs) to study the effect of electrondonating groups on the device performance. The three compounds, DPP-APh, DPP-A-Na, and DPP-A-An, possessed intense absorption bands that covered a wide range, from 350 to 750 nm, and relatively low HOMO energy levels, from -5.50 to -5.55 eV. DPP-A-An, which contained anthracene end-groups, demonstrated a stronger absorbance and a higher hole mobility than DPP-A-Ph, which contained phenyl groups, and DPP-A-Na, which contained naphthalene units. The power-conversion efficiencies (PCEs) of OSCs based on organic:PC71BM blends (1:1, w/w) with a processed DIO additive were 3.93% for DPP-A-An, 3.02% for DPP-Na, and 2.26% for DPP-A-Ph. These findings suggest that a DPP core that is functionalized with electron-donating capping groups constitutes a promising new class of solution- processable small molecules for OSC applications [ABSTRACT FROM AUTHOR]

ABSTRACT Low bandgap polymers with dithienylquinoxaline moieties based on 6H-phenanthro[1,10,9,8- cdefg]carbazole were synthesized via the Suzuki coupling reaction. Alkoxy groups were substituted at two different positions on the phenyl groups of the quinoxaline units of these polymers: in the para-position (PPQP) and in the meta-position (PPQM). The two polymers showed similar physical properties: broad absorption in the range of 400-700 nm, optical bandgaps of ∼1.8 eV, and the appropriate frontier orbital energy levels for efficient charge transfer/separation at polymer/PC71BM interfaces. However, the PPQM solar cell achieved a higher PCE due to its higher Jsc. Our investigation of the morphologies of the polymer:PC71BM blend films and theoretical calculations of the molecular conformations of the polymer chains showed that the polymer with the meta-positioned alkoxy group has better miscibility with PC71BM than the polymer with the para-positioned alkoxy group because the dihedral angle of its phenyl group with respect to the quinoxaline unit is higher. This higher miscibility resulted in a polymer:PC71BM blend film with a better morphology and thus in a higher PCE. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 796-803 [ABSTRACT FROM AUTHOR]

Highlights: [•] New copolymers based dialkylterthiophene. [•] Among copolymers, PBTOT had relatively good solubility and crystalline structure. [•] PBTOT showed field effect mobility of 1.73×10−2 cm2 V−1 S−1. [•] PBTOT showed power conversion efficiency of 3.2%. [ABSTRACT FROM AUTHOR]

Highlights: [•] New quinquethiophene end-capped anthracene. [•] Solution processed organic thin film transistor. [•] Ordered crystalline structure. [ABSTRACT FROM AUTHOR]

High-precision position estimations of agricultural mobile robots (AMRs) are crucial for implementing control instructions. Although the global navigation satellite system (GNSS) and real-time kinematic GNSS (RTK-GNSS) provide high-precision positioning, the AMR accuracy decreases when the signals interfere with buildings or trees. An improved position estimation algorithm based on multisensor fusion and autoencoder neural network is proposed. The multisensor, RTK-GNSS, inertial-measurement-unit, and dual-rotary-encoder data are fused with Extended Kalman filter (EKF). To optimize the EKF noise matrix, the autoencoder and radial basis function (ARBF) neural network was used for modeling the state equation noise and EKF measurement equation. A multisensor AMR test platform was constructed for static experiments to estimate the circular error probability and twice-the-distance root-mean-squared criteria. Dynamic experiments were conducted on road, grass, and field environments. To validate the robustness of the proposed algorithm, abnormal working conditions of the sensors were tested on the road. The results showed that the positioning estimation accuracy was improved compared to the RTK-GNSS in all three environments. When the RTK-GNSS signal experienced interference or rotary encoders failed, the system could still improve the position estimation accuracy. The proposed system and optimization algorithm are thus significant for improving AMR position prediction performance. [ABSTRACT FROM AUTHOR]

In article number 2001990, Jingon Jang, Gunuk Wang, and co-workers have reported a new type of transparent and unipolar nonvolatile memory that is developed based on a two-terminal Pt/ZnAl-LDH/FTO junction, where its switching filament is formed through the self-organized vertical stacked ZnAl-LDH structure. Transparent and Unipolar Nonvolatile Memory: Transparent and Unipolar Nonvolatile Memory Using 2D Vertically Stacked Layered Double Hydroxide (Adv. Keywords: 2D materials; layered double hydroxide-based nanocomposites; transparent memory; unipolar switching memory EN 2D materials layered double hydroxide-based nanocomposites transparent memory unipolar switching memory 1 1 1 05/26/21 20210521 NES 210521 Layered double hydroxide (LDH)-based materials, which are 2D materials, have received considerable attention because of their structural diversity and electronic functionality. [Extracted from the article]