Strain-restricted transfer of ferromagnetic electrodes for constructing reproducibly superior-quality spintronic devices.

Spintronic device is the fundamental platform for spin-related academic and practical studies. However, conventional techniques with energetic deposition or boorish transfer of ferromagnetic metal inevitably introduce uncontrollable damage and undesired contamination in various spin-transport-channel materials, leading to partially attenuated and widely distributed spintronic device performances. These issues will eventually confuse the conclusions of academic studies and limit the practical applications of spintronics. Here we propose a polymer-assistant strain-restricted transfer technique that allows perfectly transferring the pre-patterned ferromagnetic electrodes onto channel materials without any damage and change on the properties of magnetism, interface, and channel. This technique is found productive for pursuing superior-quality spintronic devices with high controllability and reproducibility. It can also apply to various-kind (organic, inorganic, organic-inorganic hybrid, or carbon-based) and diverse-morphology (smooth, rough, even discontinuous) channel materials. This technique can be very useful for reliable device construction and will facilitate the technological transition of spintronic study.

Van der Waals Multilayer Heterojunction for Low-Voltage Organic RGB Area-Emitting Transistor Array.

Organic light-emitting transistors (OLETs) have garnered considerable attention from academy and industry due to their potential applications in next-generation display technologies, multifunctional devices, and organic electrically pumped lasers. However, overcoming the trade-offs among power consumption, external quantum efficiency (EQE), and uniform area emission remains a long-standing issue for OLETs. Herein, a van der Waals multilayer heterojunction methodology is proposed to enhance the layer-to-layer interfacial interaction and contact, resulting in better dipole shielding, carrier transport, exciton recombination, and current density distribution. The prepared multilayer heterojunction OLET (MLH-OLET) array shows uniform and bright RGB area emission and low operating voltage (<30 V among the lowest applied voltage of reported lateral LETs). Additionally, a high brightness under area emission of 1060 cd m-2 , a high EQE value of 0.85%, and a high loop stability (over 380 cycles, outperforming state-of-the-art OLETs) indicate that the proposed multilayer heterojunction is obviously superior to the reported lateral device configuration. The van der Waals multilayer heterojunction developed for the preparation of OLET arrays sufficiently meets the low-voltage, high-performance, and low-cost requirements of future display technologies.

Continuous Room-Temperature Spin-Injection Modulation Achieved by Spin-Filtering Competition in Molecular Spin Valves.

Abundant spin-related phenomena that originate from interfaces between ferromagnetic electrodes and molecular semiconductors have greatly enriched research in spintronics, and they are considered promising for realizing novel spintronic functionalities in the future. However, despite great effort, the interfacial effect cannot be precisely controlled to achieve steady and predictable functions, especially at room temperature, and this has gradually become a significant bottleneck in the development of molecular spintronics. In this study, an innovative spin-filtering-competition mechanism is proposed to continuously modulate the interfacial effect in molecular spin valves at room temperature. To form this novel mechanism, the original spin-filtering effect from pure cobalt competes with the newly generated one, which is induced by the bonding effect between cobalt and lithium fluoride. Subsequently, by precisely controlling competition through lithium fluoride coverage on the cobalt surface, continuous modulation of the spin-injection process can be successfully achieved at room temperature. Spin polarization of the injected current and magnetoresistance effect can be actively controlled or their sign can be completely reversed through this novel mechanism. This study provides an innovative approach and theory for precisely controlling spin-related interfacial effects, which may further promote the scientific and technological development of spintronics.

Fiber-Based, Double-Sided, Reduced Graphene Oxide Films for Efficient Solar Vapor Generation.

Solar vapor generation is a promising and whole new branch of photothermal conversion for harvesting solar energy. Various materials and devices for solar thermal conversion were successively produced and reported for higher solar energy utilization in the past few years. Herein, a compact device of reduced graphene oxides (rGO) and paper fibers was designed and assembled for efficient solar steam generation under light illumination, and it consists of water supply pipelines (WSP), a thermal insulator (TI) and a double-sided absorbing film (DSF). Heat localization is enabled by the black DSF due to its broad absorption of sunlight. More importantly, the heat transfer, from the hot DSF to the cold base fluid (water), was suppressed by TI with a low thermal conductivity. Meanwhile, bulk water was continuously transported to the DSF by WSP through TI, which was driven by the surface energy and surface tension based on the capillary effect. The effects of reduction degrees of rGO on the photothermal conversion were explored, and the evaporation efficiency reached 89.2% under one sun with 60 mg rGO. This new microdevice provided a basic technical support for distillation, desalination, sewage treatment, and related technologies.