The high sensitivity (260.75 mA mM⁻¹) detection of an extremely low concentration (300 nM) glucose solution is demonstrated by the bilayer MoS₂ FET based biosensor.

In digital microfluidics, droplet generation is a fundamental operation for quantitative liquid manipulation. The generation of well-defined micro-droplets on a chip with restricted device geometries has become a real obstacle for digital microfluidics platforms to be used in parallel for in vitro diagnostic applications. Here, we propose a “one-to-three” droplet splitting technique that is able to generate sub-microlitre droplets beyond the “well-known” geometry limit in electrowetting-on-dielectric digital microfluidics. Accordingly, we realized an on-chip magnetic bead chemiluminescence immunoassay for parallel detection with the “one-to-three” technique. With the help of the generated micro droplets, we were able to retain the magnetic beads by a significantly reduced magnetic force. We have shown the detection of five B-type natriuretic peptide analyte samples on a single chip for around 10 minutes. The correlation coefficient of the calibration curve was 0.9942, and the detection limit was lower than 5 pg mL⁻¹.

Advanced infrared optoelectronic devices fabricated using antimony-based type-II superlattices have progressed significantly in recent years. However, fundamental challenges remain in the understanding of the exciton recombination mechanism associated with these superlattice structures and in the exploration of efficient methods to suppress the effects of native defects and thus prolong carrier lifetimes. We have investigated the optical properties of high-quality InAs/In0.5Ga0.5As0.5Sb0.5 type-II superlattices in the long-wave infrared band (6–9 μm), where a significant carrier localization phenomenon was observed via temperature- and excitation-power-dependent photoluminescence measurements. The carrier distribution with respect to temperature, including the anomalous temperature dependences of the peak energy, the full width at half maximum, and the integrated intensities, were identified and explained using the localized-state ensemble luminescence model. We also observed a large radiative to nonradiative recombination ratio (∼42.6) by analyzing localized-state ensemble equations in type-II superlattices. Finally, the InAs/In0.5Ga0.5As0.5Sb0.5 superlattice showed long minority carrier lifetimes of up to 847 ns. These results show that the prepared InAs/In0.5Ga0.5As0.5Sb0.5 superlattices have excellent optical properties compared with existing type-II superlattices and have great potential for infrared optoelectronic applications.

In recent years, rare-earth metals with triply oxidized state, lanthanide ions (Ln³⁺), have been demonstrated as dopants, which can efficiently improve the optical and electronic properties of metal halide perovskite materials. On the one hand, doping Ln³⁺ ions can convert near-infrared/ultraviolet light into visible light through the process of up-/down-conversion and then the absorption efficiency of solar spectrum by perovskite solar cells can be significantly increased, leading to high device power conversion efficiency. On the other hand, multi-color light emissions and white light emissions originated from perovskite nanocrystals can be realized via inserting Ln³⁺ ions into the perovskite crystal lattice, which functioned as quantum cutting. In addition, doping or co-doping Ln³⁺ ions in perovskite films or devices can effectively facilitate perovskite film growth, tailor the energy band alignment and passivate the defect states, resulting in improved charge carrier transport efficiency or reduced nonradiative recombination. Finally, Ln³⁺ ions have also been used in the fields of photodetectors and luminescent solar concentrators. These indicate the huge potential of rare-earth metals in improving the perovskite optoelectronic device performances.

Molybdenum disulfide (MoS₂), a relatively new and exciting two-dimensional graphene-like material, has been attracting more and more attentions from the researchers due to its unique structural and fascinating properties. The potential application of MoS₂ under high-pressure and low-temperature is expected, while the related research is few at present. In this paper, quadrilayer MoS₂ was synthesized by chemical vapor deposition, and its structural properties under different pressures (0–20.7 GPa) and temperatures (10–300 K) were investigated via the Raman spectra. We find that the lattice of quadrilayer MoS₂ is not damaged and the quadrilayer MoS₂ exhibits good semiconductive properties under large variable pressures from atmospheric to 20.7 GPa, which is much different to its bulk and single crystalline phases. In addition, the lattice structures of the quadrilayer MoS₂ are stable in 10–300 K, and the Grüneisen parameters of E¹_2g and A_1g modes are smaller than that of bulk. This study indicates that quadrilayer MoS₂ has a better prospect in high-pressure and low-temperature environment.