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Memristors based on organic–inorganic halide perovskite have received intensive attention because of its solution-processability and defect-tolerant characteristics. But the lead element in perovskite is inevitably harmful to human body and environment. Herein, we report an e-synapse based on lead-free organic halide perovskite (CH3NH3)3Sb2Cl9 (MA3Sb2Cl9), which exhibits excellent mimic of biological synaptic characteristics, such as excitatory postsynaptic currents (EPSCs), inhibitory postsynaptic currents (IPSCs), and paired-pulse facilitation (PPF). Furthermore, the synaptic weight of the e-synapse is found to be dependent on the frequency of pulse stimulation. The charge conduction mechanism of the e-synapse is proposed based on the in-depth investigation of the electrical characteristics of the devices. This work demonstrates that lead-free organic perovskite MA3Sb2Cl9 provide a new perspective on engineering e-synapses for neuromorphic computing and have a great potential for environment-friendly artificial intelligence applications.

In conventional quantum dot light-emitting diodes (QLEDs), the organic charge transport materials are susceptible to erosion by water and oxygen, which would reduce the efficiency and lifetime of the devices. Herein, we modified the surface of the organic hole transport layer with an ultra-thin Al2O3 layer, which is deposited by using atomic layer deposition technique, to obtain the highly efficient and stable QLEDs. It is indicated that the ultra-thin Al2O3 interlayer plays a significant role in decreasing leakage current, suppressing exciton quenching and passivating the defects. The device with Al2O3 interface modification exhibits the maximum external quantum efficiency (EQE) of 20.8%, current efficiency (CE) of 21.6 cd A−1, and lifetime of 482000 h. In comparison with the control device, the EQE, CE and lifetime are improved by 31%, 32%, and 330%, respectively. The results indicate that the strategy of Al2O3 interface modification could provide an effective way for realizing highly efficiency QLED with long lifetime.

Simulating synaptic function and building brain-inspired computers have received widespread attention. The memristor is considered to be an electronic version of the synapse and an excellent element for creating a brand-new artificial intelligence system in the future. However, most memristor-based electronic synapses currently exhibit low stability due to complex resistance switching processes. Based on a controllable in-situ formation strategy that we were able to employ with atomic layer deposition, we fabricated electronic synapses based on Au@Al2O3 core-shell nanoparticles. Our device exhibited extremely reliable, stable, and durable performance and showed a capability to emulate biological synaptic behavior, including synaptic plasticity, long-term depression (LTD), long-term potentiation (LTP), amplitude dependence, and frequency dependence. This research provides a strategy for manufacturing highly-reliable electronic synapses for neuromorphic applications.

Although the Raman fiber amplifiers are attractive for their unique advantages and various Raman fiber amplifiers in continuous wave (CW) regime were built, there are a few fundamental limitations for short-pulsed Raman fiber amplifiers. In this paper, we present a theoretical and experimental study on a novel method termed picosecond (ps) coherent Raman fiber amplification, where the stimulated Raman scattering is employed to generate high-quality femtosecond pulses from narrowband ps pump pulses, with high conversion efficiency and compact construction. Detailed numerical simulation reveals the nonlinear dynamics of the ps-coherent Raman fiber amplification in an Yb-doped gain fiber. The spectral filtering effect induced by finite Raman gain bandwidth significantly improves the temporal quality of the generated Raman pulses, similar to the well-known Mamyshev regenerator. By employing this method in a 4.5 m Yb-doped polarization maintaining double-clad fiber, 67 nJ, 76 fs nearly transmission limited Raman pulses are generated from narrowband (

We report on an all-normal-dispersion Yb-doped fiber laser with mode-locking mechanism based on nonlinear polarization rotation. The splitting and trapping of dissipative solitons (DSs) could be observed by inserting of a short section of polarization-maintaining fiber in cavity configuration as an in-line birefringence fiber filter. Two trapped orthogonal polarization DSs can travel with the same group velocity in the laser cavity. With the DSs trapping, the polarization sidebands are appeared in the spectrum. The trapping of DSs and sideband generation is numerically simulated as well.