Tunable luminescence of Bi(3+)-doped YP(x)V(1-x)O4 (0 ≤ x ≤1).

A systematic investigation of the luminescence spectroscopy of Y(P,V)O4:Bi(3+) is presented. The emission spectra and the decay curves are measured as a function of the host morphology, composition, temperature, excitation wavelength, and doping concentration. On this basis, the nature of the excited states and the radiative and non-radiative relaxation processes are discussed.

Photoswitching of bis-spiropyran using near-infrared excited upconverting nanoparticles.

Bis-spiropryran molecules were grafted onto the surface of upconverting nanoparticles. Fluorescence resonance energy transfer from the upconverting nanoparticles to the surface bis-spiropyran molecules triggered the transformation of the ring-closed bis-spiropyran to the ring-open bis-merocyanine forms.