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Single- or few-layer forms of black phosphorus, so called phosphorene, were isolated by exfoliation in 2014 as 2D layered materials holding great promise in electronic and optoelectronic fields. In this perspective, we highlight recent developments in black phosphorus research, in particular, we will focus on the mechanical properties of its 2D form. Its unique puckered structure is responsible for strong anisotropy in mechanical and transport properties, different from graphene and transition-metal dichalcogenide 2D materials. This peculiar mechanical anisotropy can be exploited for applications such as nanomechanical resonators, thermoelectric devices, and motion sensors with tunable functions inaccessible by isotropic materials. Current bottlenecks hindering further progress in devices applications involve first surface degradation in environmental conditions which, in turn, can be exploited in surface friction mechanics to achieve superlubricity. In this framework, the investigation of mechanical properties of phosphorene will be pivotal for facile fabrication, transfer, and resolution of technical hurdles as well the discovery of novel applications. As research directions in next foreseeable future, we will discuss the challenge of crosstalk between mechanical and transport properties, in particular, how the stress–strain stimulations can be used to tune optoelectronic and thermoelectric performance.

Black phosphorus (BP) as a two-dimensional semiconductor has attracted tremendous interest in physics, chemistry, biology, and engineering fields. BP has a thickness-dependent bandgap and high carrier mobility, and its puckered honeycomb layer structure with in-plane anisotropy gives rise to unique electrical, thermal, optical, and other properties. These interesting properties provide new opportunities for the design of new devices. The prominent electrical and thermal properties of BP are orthogonal, and the Seebeck coefficients of BP, especially monolayer BP, are large, thus rendering the materials to be desirable in thermoelectric devices. In this Perspective, the recent developments of electrical, thermal, and thermoelectric properties of BP are described. The strategies to tailor the thermoelectric performance are highlighted, aiming at further development and applications in highly efficient thermoelectric devices.

Au nanorods have been successfully synthesized at 90C by using hexadecyltrimethylammonium bromide (CTAB) and benzyldimethylammoniumchloride hydrate (BDAC) co-surfactant. At 90C, the reaction time was less than 10 s, and the longitudinal surface plasmon absorption band could vary between 680 and 770 nm by adjusting the molar ratio of BDAC to CTAB from 2 to 0.5. At 90C, nanorods with a longitudinal surface plasmon absorption peak of 770 nm can be obtained when the molar ratio of BDAC to CTAB was 3:2.

The excellent optical properties of europium-doped crystals in visible and near infrared wavelength regions enable them to have broad applications in optoelectronics, laser crystals and sensing devices. The local site crystal fields can affect the intensities and peak positions of the photo-emission lines strongly, but they are usually difficult to be clarified due to magnetically degenerate 4f electronic levels coupling with the crystal fields. Here, we provide an effective way to explore the hidden local symmetry of the Eu3+ sites in different hosts by taking photoluminescence measurements under pulsed high magnetic fields up to 46 T. The zero-field photoluminescence peaks split further at high magnetic fields when the Zeeman splitting energy is comparable to or larger than that of the crystal field induced zero-field splitting. In particular, a magnetic field induced crossover of the local crystal fields has been observed in the GdVO4:Eu3+ crystal, which resulted from the alignment of Gd3+ magnetic mom...

Semiconductor nanocrystals (SNCs) doped with Mn2+ and Cu2+ ions (ZnSe:Mn, ZnSe:Mn/CdSe, and ZnSe:Cu) were synthesized and their nonlinear absorption properties were investigated using the typical open-aperture Z-scan technique. A reversal from reverse saturable absorption (RSA) to saturable absorption (SA) was observed in the ZnSe:Mn SNCs. In contrast, the SA signals were largely suppressed and only RSA signals were measured in the ZnSe:Mn/CdSe and ZnSe:Cu SNCs. These different nonlinear absorption properties implied strong interactions between the excited excitons and impurity ions, which agreed well with the analysis performed by the theory model of the exciton transition in the energy structures. The nonlinearities of the doped SNCs could be controllably tuned by the integration of different doped ions and host SNCs. This strategy shows promise for extensive potential applications in optical limiting and switching.

We report efficient and long-lived exciton photoluminescence (PL) from inverted core/shell ZnSe:Mn/CdSe nanocrystals (NCs) at room temperature. Contrary to low temperature-sensitivity of Mn2+ PL from ZnSe:Mn/ZnSe NCs, the Mn2+-assisted excitonic PL from the ZnSe:4%Mn/CdSe NCs exhibits unusually high temperature-sensitivity (−2.4% per K) in the temperature range 298–334 K, which is even higher than that of the pure excitonic PL from the undoped ZnSe/CdSe NCs. Such unexpected temperature-dependence of the Mn2+-assisted excitonic PL is well explained by the deduced exciton rate equation involving the exciton-Mn2+ resonant energy transfer in the ZnSe:Mn/CdSe NCs.

We report the polyol synthesis and crystal structure characterization of silver nanorings, which have perfect circular shape, smooth surface, and elliptical wire cross-section. The characterization results show that the silver nanorings have well-defined crystal of singly twinned along the whole ring. The spatial distribution of the scattering of a silver nanoring with slanted incidence reveals the unique focus effect of the nanoring, and the focus scattering varies with the incident wavelength. The silver nanorings with perfect geometry and well-defined crystal have potential applications in nanoscaled photonics, plasmonic devices, and optical manipulation.