The semiconductor oxide BiVO₄ was adopted as a novel host for highly efficient upconversion luminescence and non-contact temperature sensing.

Although it is known that the Raman spectroscopic signature of single-walled carbon nanotubes (SWCNTs) is highly chirality dependent, using Raman spectroscopy as a tool for quantifying fraction of either metallic or semiconducting nanotubes in a sample has become a widely used analytical method. In this work, using the electron diffraction technique as a basis, we have examined the validity of Raman spectroscopy for quantitative evaluation of metallic fractions (M%) in single-walled carbon nanotube samples. Our results show that quantitative Raman spectroscopic evaluations of M%, either by using integrated intensities of chirality-associated radial breathing modes (RBMs), or, as has been more commonly utilized in recent studies, by statistically counting the numbers of RBMs, are misrepresentative. Specifically, we have found that the occurrence numbers of certain types of RBMs in Raman spectral mapping depend critically on the diameter distribution, resonant coupling between transition energies and excitation laser energy, and the chirality-dependent Raman scattering cross sections, rather than simply on the metallic and semiconducting SWCNT fractions. These dependences are similar to those observed in the integrated intensities of RBMs. Our findings substantially advance the understanding of the proper use of Raman spectroscopy for carbon nanotube quantification, which is important for carbon nanotube characterization and crucial to guide research in SWCNT growth and their applications.

We demonstrate the realization of steady-state three-primary-color emission in single NaYF₄-based up-conversion nanoparticles with a simple five-layer core-shell structure. These nanoparticles show promising potential applications in dynamic display and anti-counterfeiting.

We report on a highly sensitive optical temperature sensing material based on two thermally coupled energy levels (⁴I_15/2 and ⁴F_9/2) of Dy³⁺.