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.

Perovskite materials and their optoelectronic devices have attracted intensive attentions in recent years. However, it is difficult to further improve the performance of perovskite devices due to the poor stability and the intrinsic deep level trap states (DLTS), which are caused by surface dangling bonds and grain boundaries. Herein, the CH 3 NH 3 PbBr 3 perovskite microcrystal is encapsulated by a dense Al 2 O 3 layer to form a microenvironment. Through optical measurement, it is found that the structure of perovskite can be healed by itself even under high temperature and long-time laser illumination. The DLTS density decreases nearly an order of magnitude, which results in 4-14 times enhancement of light emission. The observation is ascribed to the micron-level environment, which serves as a self-sufficient high-vacuum growth chamber, where the components of the perovskite are completely retained when sublimated and the decomposed atoms can re-arrange after thermal treatment. The modified structure showing high thermal stability is able to maintain excellent optical and lasing stability up to 2 years. This discovery provides a new idea and perspective for improving the stability of perovskite and can be of practical interest for perovskite device application.

Understanding of ultrafast carrier dynamics in InP/ZnS colloidal quantum dots (QDs) is essential for their optoelectronic applications. In this paper, we have successfully fabricated high-quality InP/ZnS core–shell QDs with quantum yield (QY) of 47%. Time-resolved photoluminescence (TRPL) and femtosecond transient absorption (TAS) measurements were performed to characterize the carrier injection, relaxation, and transition process in the InP/ZnS QDs. It is found that the photoexcited carrier first injected to the ZnS shell in 2 ps, then relaxed to the alloyed layer between the ZnS shell and InP core in 7.4 ps, next relaxed to different energy levels in the InP core in about 170 ps, and finally recombined by charged and neutral excitons transition in 4.1 and 26.7 ns, respectively. Additionally, the two-photon absorption (TPA) coefficient obtained from Z-scan measurement indicates that InP/ZnS QDs possess good nonlinearly optical properties. Our research is significant for the improvement and engineering of InP/ZnS QDs-based materials for optoelectronic applications.

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 E12g and A1g modes are smaller than that of bulk. This study indicates that quadrilayer MoS2 has a better prospect in high-pressure and low-temperature environment.

No abstract