Simulating the human brain for neuromorphic computing has attractive prospects in the field of artificial intelligence. Optoelectronic synapses have been considered to be important cornerstones of neuromorphic computing due to their ability to process optoelectronic input signals intelligently. In this work, optoelectronic synapses based on all‐inorganic perovskite nanoplates are fabricated, and the electronic and photonic synaptic plasticity is investigated. Versatile synaptic functions of the nervous system, including paired‐pulse facilitation, short‐term plasticity, long‐term plasticity, transition from short‐ to long‐term memory, and learning‐experience behavior, are successfully emulated. Furthermore, the synapses exhibit a unique memory backtracking function that can extract historical optoelectronic information. This work could be conducive to the development of artificial intelligence and inspire more research on optoelectronic synapses.
Anticounterfeiting
techniques based on physical unclonable functions
exhibit great potential in security protection of extensive commodities
from daily necessities to high-end products. Herein, we propose a
facile strategy to fabricate an unclonable super micro fingerprint
(SMFP) array by introducing in situ grown perovskite crystals for
multilevel anticounterfeiting labels. The unclonable features are
formed on the basis of the differential transportation of a microscale
perovskite precursor droplet during the inkjet printing process, coupled
with random crystallization and Ostwald ripening of perovskite crystals
originating from their ion crystal property. Furthermore, the unclonable
patterns can be readily tailored by tuning in situ crystallization
conditions of the perovskite. Three-dimensional height information
on the perovskite patterns are introduced into a security label and
further transformed into structural color, significantly enhancing
the capacity of anticounterfeiting labels. The SMFPs are characterized
with tunable multilevel anticounterfeiting properties, including macroscale
patterns, microscale unclonable pattern, fluorescent two-dimensional
pattens, and colorful three-dimensional information.
Smart windows with adjustable transmittance via physical stimuli are eagerly desired for sorts of energy‐saving lighting systems. However, reciprocal trade‐off relationship such as high transparency and coloration/discoloration ability exists in smart windows, not conducive to optical‐electrical coupling and leap in performance. Substituting for common composites utilized in smart windows, here, single transparent ceramic‐based smart windows are reported through composition design and defect management strategies to regulate the optoelectronic performances and break off the contradictions between optical transmittance, photo‐thermochromism and electrical conductivity. By first principles calculations and precisely tuning Er3+, Ba2+, Sr2+ concentrations in non‐stoichiometric Er‐doped (K0.5Na0.5)NbO3‐(Ba, Sr)TiO3, the fabricated ceramics exhibit brilliant transparency and multi‐mode dramatical and reversible modulations of pellucidity, photoluminescence intensity, along with conductivity (over fivefold variation), enabling prominent optoelectronic information storage and modulating capacity in vivid potential applications, such as easy‐readout/erasable optical memorizers, photo‐memristors and anti‐counterfeiting displays.
Multi-mode modulations of near-infrared and visible optical behaviors in xNd-KNN translucent ceramics are induced by color center-related photochromism reactions.
Some tungsten-bronze compounds in the BaO–Nd2O3–TiO2–Nb2O5 system were prepared and characterized. Ba4Nd2Ti4Nb6O30 and Ba5NdTi3Nb7O30 had the filled tetragonal tungsten-bronze structure, and Ba3Nd3Ti5Nb5O30 consisted of the tetragonal tungsten-bronze major phase and a minor amount of secondary phase BaNd2Ti3O10. These compounds had significant relaxor behaviors, and the Curie temperatures (at 1 MHz) were 0 and 55 °C for Ba3Nd3Ti5Nb5O30 and Ba5NdTi3Nb7O30 ceramics, respectively. A high dielectric constant (213) combined with low dielectric loss (0.004 at 1 MHz) was obtained in Ba3Nd3Ti5Nb5O30 ceramics. In addition, the solid-solution range of BapNd6−pTi8−pNb2+pO30 was 3 < p ≤ 6.
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