Fully degradable biomimetic synaptic devices based on a W/MgO/ZnO/Mo memristor on a silk protein substrate show remarkable information storage and synaptic characteristics.

This study investigated brittle solder joint failure mechanisms during high-speed solder ball shear and pull testing. BGA package samples with different solder alloys (Sn4.0%AgO.5%Cu and Sn37%Pb) were fabricated and a series of solder ball shear and pull tests were conducted at various testing speeds. The ball shear test speeds ranged from 10 mm/s to 3000 mm/s, while the ball pull test speeds ranged from 5 mm/s to 500 mm/s. Following high-speed shear/pull testing, the brittle fracture surfaces of the solder balls and corresponding pad were inspected using SEM/EDX. The results describe an increased incidence of brittle interfacial fracture for SnAgCu solder compared to SnPb solder. Microstructure analysis of brittle solder joint fracture surfaces appears an effective method to aid correlation between board level drop test and high-speed solder ball shear/pull tests.

The worldwide popularization of white-light-emitting diode (WLED) lighting brings about chronic blue-light exposure, which has severe negative impacts on human health and circadian rhythm. The blue-light hazard can be readily minimized by developing violet LED chip (λ em ≈ 400 nm)-pumped sustainable and human-centric WLED lighting. However, the development of sustainable healthy lighting is stringently restricted because few blue phosphors can be efficiently pumped by violet LED chips. Herein, we report a novel Na 3 KMg 7 (PO 4 ) 6 :Eu 2+ blue phosphor with high quantum efficiency (>90%) and color purity (95.4%), which can efficiently convert violet light to blue emission. A crystal-site engineering approach and density functional theory (DFT) prove that the narrow-band (FWHM = 41 nm) emission of the Na 3 KMg 7 (PO 4 ) 6 :Eu 2+ phosphor originates from the accommodation of Eu 2+ dopants in the Na(2) site. More importantly, the Na 3 KMg 7 (PO 4 ) 6 :Eu 2+ phosphor shows zero-thermal-quenching luminescence due to a large band gap (>6 eV). By depositing the commercial Sr 2 Si 5 N 8 :Eu 2+ red phosphor, β-SiAlON:Eu 2+ green phosphor, and as-synthesized Na 3 KMg 7 (PO 4 ) 6 :Eu 2+ blue phosphor on a 400 nm violet LED chip, the prototypical WLED can emit fullspectrum warm white light (R a = 94.3) with significantly diminished blue-light intensity. The outstanding Na 3 KMg 7 (PO 4 ) 6 :Eu 2+ blue phosphor reported here can speed up the industrialization of human-centric WLED lighting.

Transient memristors are prospective candidates for both secure memory systems and biointegrated electronics, which are capable to physically disappear at a programmed time with a triggered operation. However, the sneak current issue has been a considerable obstacle to achieve high-density transient crossbar array of memristors. To solve this problem, it is necessary to develop a transient switch device to turn the memory device on and off controllably. Here, a dissolvable and flexible threshold switching (TS) device with a vertically crossed structure is introduced, which exhibits a high selectivity of 10 , steep turn-on slope of <8 mV dec , and fast ON/OFF switch speed within 50/25 ns. Triggered failure could be achieved after soaking the device in deionized water for 8 min at room temperature. Furthermore, a water-assisted transfer printing method is used to fabricate flexible and transient TS device arrays for bioresorbable systems, in which none of any significant degradation is observed under a bending radius of 2 mm. Integrating the selector with a transient memristor is capable of 10 Gb memory implementation, indicating that the transient TS device could provide great opportunities to achieve highly integrated transient memory arrays.