An adjustable multistage resistance switching behavior of a photoelectric artificial synaptic device with a ferroelectric diode effect for neuromorphic computing.

Neuromorphic computing, which mimics biological neural networks, is widely regarded as the optimal solution for addressing the limitations of traditional von Neumann computing architecture. In this work, an adjustable multistage resistance switching ferroelectric Bi2FeCrO6 diode artificial synaptic device was fabricated using a sol-gel method with a simple process. The device exhibits nonlinearity in its electrical characteristics, demonstrating tunable multistage resistance switching behavior and a strong ferroelectric diode effect through the manipulation of ferroelectric polarization. One of its salient advantages resides in its capacity to dynamically regulate its polarization state in response to an external electric field, thereby facilitating the fine-tuning of synaptic connection strength while maintaining synaptic stability. The device is capable of accurately simulating the fundamental properties of biological synapses, including long/short-term plasticity, paired-pulse facilitation, and spike-timing-dependent plasticity. Additionally, the device exhibits a distinctive photoelectric response and is capable of inducing synaptic plasticity by light signal activation. The utilization of a femtosecond laser for the scrutiny of carrier transport mechanisms imparts profound insights into the intricate dynamics governing the optical memory effect. Furthermore, utilizing a convolutional neural network (CNN) architecture, the recognition accuracy of the MNIST and fashion MNIST datasets was improved to 95.6% and 78%, respectively, through the implementation of improved random adaptive algorithms. These findings present a new opportunity for utilizing Bi2FeCrO6 materials in the development of artificial synapses for neuromorphic computation.

In situ cyclodextrin metal-organic framework/electrospun composite fibers with biosafety for the removal of volatile organic compounds.

Volatile organic compounds (VOCs) are one of the most common air pollutants, which threaten human health seriously. Fibrous textile is one of the most popular matrices for VOC removal in daily life. In this study, biosafe cyclodextrin metal-organic framework/polycaprolactone (CD-MOF/PCL) electrospun fibers were prepared via a CD precursor doping method, followed by hydrothermal treatment in methanol vapor diffusion. In situ CD-MOF crystals with a high loading of more than 50 wt% densely covered the surface of the electrospun fibers. The CD-MOF/PCL composite fibers show similar stress-strain behavior to the electrospun PCL fibers. The analysis of the fractured zone indicated that the compatibility of CD-MOF/PCL fibers was excellent, and CD-MOF showed no obvious peeling-off, even at low temperatures. The hemolysis rate of less than 1% confirms the biosafety of the composite materials. Further, the CD-MOF crystals anchored onto the fibers promote their VOC uptakes significantly. The CD-MOF/PCL fibrous matrix, which demonstrated compatibility, excellent strength, and biosafety would be beneficial to develop novel equipment to purify air pollution.

Facilitation of molecular motion to develop turn-on photoacoustic bioprobe for detecting nitric oxide in encephalitis.

Nitric oxide (NO) is an important signaling molecule overexpressed in many diseases, thus the development of NO-activatable probes is of vital significance for monitoring related diseases. However, sensitive photoacoustic (PA) probes for detecting NO-associated complicated diseases (e.g., encephalitis), have yet to be developed. Herein, we report a NO-activated PA probe for in vivo detection of encephalitis by tuning the molecular geometry and energy transformation processes. A strong donor-acceptor structure with increased conjugation can be obtained after NO treatment, along with the active intramolecular motion, significantly boosting "turn-on" near-infrared PA property. The molecular probe exhibits high specificity and sensitivity towards NO over interfering reactive species. The probe is capable of detecting and differentiating encephalitis in different severities with high spatiotemporal resolution. This work will inspire more insights into the development of high-performing activatable PA probes for advanced diagnosis by making full use of intramolecular motion and energy transformation processes.