Developing dielectric ceramics with high energy storage performance (ESP) is essential for miniaturizing and integrating high-power pulse capacitors. Sr 2 NaNb 5 O 15 -based tungsten bronze ferroelectric ceramics have been highly investigated for dielectric energy storage applications recently. However, the difficulty in concurrently obtaining large polarization and strong relaxor characteristics greatly hinders the ESP improvement. In this work, Bi 3+ and Ti 4+ ions were introduced into the Sr 2 NaNb 5 O 15 ceramic, aiming to modulate the ferroelectric polarization and relaxor behavior synergistically. An excellent recoverable energy density ( W rec ∼ 4.08 J/cm 3 ) and a high efficiency ( η ∼ 84.59%) were concurrently attained in the Sr 1.85 Bi 0.15 NaNb 4.85 Ti 0.15 O 15 composition due to the boosted polarization and enhanced relaxor nature. Moreover, this ceramic also exhibited a high current density (863.06 A/cm 2 ) and a large power density (94.94 MW/cm 3 ). All these characteristics demonstrate that the Bi 3+ and Ti 4+ ions co-doped Sr 2 NaNb 5 O 15 ceramics possess great potential for dielectric capacitor applications.
Synergistically modulating electron distribution between metal nodes in metal–organic frameworks (MOFs) is an effective strategy to improve the electrocatalytic performance of MOFs. Herein, a special bimetallic MOF composite (Al0.35/Ru0.15-TCPP-CNTs) was constructed by introducing highly dispersed Ru and Al co-existing in the MOF metal clusters and combining them with conductive carboxylic multi-walled carbon nanotubes (CNTs). Notably, the catalyst exhibited excellent hydrogen evolution reaction (HER) performance, with an overpotential of as low as 32 mV at a current density of 10 mA cm−2 in acidic media, comparable to commercial Pt/C. Experimental results and density functional theory (DFT) calculations proved that a reasonable proportion of Al/Ru bimetallic clusters in MOFs and the loaded CNTs induced charge redistribution and cooperative electronic coupling, which not only optimized the adsorption energy of H intermediates (ΔGH*) and produced a possible hydrogen spillover effect, but also increased the specific surface area and facilitated electron/mass transfer. This work may provide an improved method and research idea for the study of MOF electrocatalysts at the atomic level.
Qian Gao,Gang He,Bo He,Yanmei Liu,Yongli He,Shanshan Jiang,Huanhuan Wei,Can Fu
The development of high-performance neuromorphic phototransistors plays a fundamental role in advancing image perception systems by enabling low-latency, event-driven light sensing and accelerating the training of memory-efficient deep neural networks. Here, artificial synaptic phototransistors with synaptic plasticity are fabricated based on La-doped In2O3 nanofibers (InLaO NFs), demonstrating an integrated artificial synapse that mimics both central and visual neural functions. The device exhibits not only exceptional electrical performance, with a high field-effect mobility of 7.70 cm2V-1s-1, an ultralarge ON/OFF current ratio (>1 × 108), but also a strong photoresponse of 28.2 nA under light illumination. Through excitatory response modes, fundamental biological functions, including excitatory postsynaptic current (EPSC), paired-pulse facilitation (PPF), and the transition from short-term plasticity (STP) to long-term plasticity (LTP), are simulated by the synaptic transistor. Furthermore, in optoelectronic co-modulation, the high synaptic weights enable the device to emulate complex neural learning rules relevant to neuromorphic applications, such as classically conditioned reflexes and image recognition tasks. These results highlight the potential of InLaO NFs-based synaptic transistors as promising candidates for bio-inspired synaptic devices and advanced neuromorphic systems.
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