A 5 × 5 ionotronic junctionless indium-tin oxide (ITO) transistor array is reported for emulating a nociceptor network based on controlling the gate-to-channel distance.

Detection and manipulation of spin current lie in the core of spintronics. Here we report an active control of a net spin Hall angle, θ_SHE(net), in Pt at an interface with a ferroelectric material PZT (PbZr_0.2Ti_0.8O₃), using its ferroelectric polarization. The spin Hall angle in the ultra-thin Pt layer is measured using the inverse spin Hall effect with a pulsed tunneling current from a ferromagnetic La_0.67Sr_0.33MnO₃ electrode. The effect of the ferroelectric polarization on θ_SHE(net) is enhanced when the thickness of the Pt layer is reduced. When the Pt layer is thinner than 6 nm, switching the ferroelectric polarization even changes the sign of θ_SHE(net). This is attributed to the reversed polarity of the spin Hall angle in the 1^st-layer Pt at the PZT/Pt interface when the ferroelectric polarization is inverted, as supported by the first-principles calculations. These findings suggest a route for designing future energy efficient spin-orbitronic devices using ferroelectric control.

Manipulation of tunneling spin-polarized electrons via a ferroelectric interlayer sandwiched between two ferromagnetic electrodes, dubbed multiferroic tunnel junctions (MFTJs), can be achieved not only by the magnetic alignment of two ferromagnets, but also by the electric polarization of the ferroelectric interlayer; this provides great opportunities for next-generation multistate memory devices. Here, we show that a ${\mathrm{La}}_{0.67}{\mathrm{Sr}}_{0.33}{\mathrm{Mn}\mathrm{O}}_3(\mathrm{LSMO})/{\mathrm{Pb}\mathrm{Zr}}_{0.2}{\mathrm{Ti}}_{0.8}{\mathrm{O}}_3(\mathrm{PZT})/\mathrm{Co}$ structured MFTJ device can exhibit multilevel resistance states in the presence of gradually reversed ferroelectric domains via tunneling electroresistance and tunneling magnetoresistance, respectively. Nonvolatile ferroelectric control in the MFTJ can be attributed to separate contributions that arise from two independent ferroelectric channels in the PZT interlayer with opposite polarization. Our study shows the dominant role of “mixed” ferroelectric states on achieving accumulative electrical modulation of multilevel resistance states in MFTJs; thus paving the way for multifunctional device applications.

A low-temperature fabrication routine is developed for hole-conductor-free and mesoscopic perovskite solar cells using a TiO₂ nanoparticle-binding carbon electrode as the top electrode. Vacuum treatment is adopted to help the infiltration and formation processes of the organic–inorganic hybrid perovskite crystallites. It is observed that such treatment not only condenses the mesoporous skeleton and improves film conductance of the carbon electrode but also makes the perovskite crystallites grow in the core part of the mesoporous skeleton. As such, the extraction process of photogenerated charge carriers is accelerated due to the strengthened interfacial contact between the perovskite crystallites and the skeleton. Accordingly, the photo-to-electric power conversion efficiency of the low-temperature devices is upgraded from 7.38 (±1.40)% to 10.17 (±0.86)% (optimized at 12.29%, AM 1.5 G, 100 mW/cm²). In addition, prolonged stability is observed. Due to the condensed device structure, storage stability of 225 days has been achieved in ambient air (with relative humidity of about 40–60%), even without encapsulation. The proposed strategy is helpful in further reducing the production cost.

Inkjet printing has become a promising, efficient, inexpensive, scalable technique for materials deposition, mask-less and digital patterning in many device applications. Meanwhile, the ink preparation remains a challenge especially for printing functional oxide materials. Based on the principles of inkjet printing (especially relevant for piezoelectric drop-on-demand inkjet printer) and the process of the conversion of liquid ink into solid thin films of oxide materials, we present two approaches to the design and tailoring of inks: (i) oxide particle suspensions (e.g. SiO ₂ , TiO ₂ , Fe ₃ O ₄ ) and (ii) metal-acetates precursor solutions for directly printing oxide thin films (e.g. ZnO, MgO, ITO and so forth). The solution inks are stable and produce tunable oxide films with high density and smooth surface. For some of the inks containing multi-type acetates with possible phase separation even before calcinations, we have developed a chelating procedure in order to tailor the films into single-phase homogeneity. The work lays a foundation for inkjet printing of oxides films for functional applications in electronic, photonic and energy devices.