Small organic molecules (SOMs) with fascinating chiroptical properties have received much attention for their potential applications in photoelectric and biological devices. As an important research tool, circularly polarized luminescence (CPL) provides information about the chiral structures of these molecules in their excited state, and has been an active area of research. With the development of the commercially available CPL instrumentation, currently, more and more research groups have attempted to enhance the CPL parameters (i.e., quantum yield and dissymmetry factor) of the chiral SOMs from all aspects. This review summarizes the latest five years progresses in research on the experimental techniques and theoretical calculations of CPL emitted from SOMs, as well as forecasting its trend of development.

We have investigated numerically toroidal dipolar excitation at optical frequency in metamaterials whose unit cell consists of three identical Ag nanodisks and a SiO2 spacer on Ag substrate. The near-field plasmon hybridization between individual Ag nanodisks and substrate forms three magnetic dipolar resonances, at normal incidence of plane electromagnetic waves. The strong coupling among three magnetic dipolar resonances leads to the toroidal dipolar excitation, when space-inversion symmetry is broke along the polarization direction of incident light. The influences of some geometrical parameters on the resonance frequency and the excitation strength of toroidal dipolar mode are studied in detail. The radiated power from toroidal dipole is also compared with that from conventional electric and magnetic multipoles.

Cubic crystalline MgZnO was grown on p-type Si (0 0 1) by a reactive e-beam evaporation system at low temperature. AES depth profiles for the MgZnO films demonstrate good uniformity of Mg, Zn and O components. MIS capacitors were fabricated and C-V and I-V characterizations were performed to evaluate the annealing effect on electrical properties of MgZnO films. High temperature annealing up to 900 • C under O 2 ambient significantly improves C-V and I-V characteristics. The interface trapped charges decrease from 5.30 × 10 12 cm −2 to 2.48 × 10 11 cm −2 as the annealing temperature increases from 550 • C to 900 • C, indicating the quality improvement of the interfacial layer. Meanwhile the density of mobile charges increases from 1.93 × 10 10 cm −2 to 1.72 × 10 11 cm −2 as the annealing temperature increases from 550 • C to 900 • C, which is attributed to the evaporation of O near the surface and migration of Zn 2+ towards the surface from MgZnO alloy film under such high temperatures.

We present an effective surface-enhancement Raman scattering (SERS) substrate enabled by depositing metallic film on a liquid surface at room temperature. Thermal evaporation is used to deposit Au atoms on silicone oil surface and then form quasi-continuous films. Due to the isotropic characteristics of the liquid surface, this film consists of substantial nanoparticles with uniform diameter, which is different from films fabricated on solid substrates and can be served as an applicable substrate for SERS detection. With the assistance of this substrate, SERS signals of rhodamine 6G were significantly enhanced, the dependence between SERS spectra and film thickness was investigated. Analytical simulation results confirm the experimental observations and the superiorities of our proposed method for preparation of SERS substrate. This work provides a potential application of metallic film deposition on free-sustained surface and holds promise as an efficient sensor in rapid trace detection of small molecule analytes.

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