Fullerene dimers have attracted extensive attention due to their unique structures and fascinating properties. Here, fullerene dimer derivatives with four to six carbon atoms in the esters are designed and synthesized. The property differences that caused by the carbon number in the esters of the fullerene dimers are investigated by performing their electrochemical, optical, and photoelectric measurements. As the carbon atom numbers in the esters increase from four to five and six, the absorption intensities increase to 1.6- and 4.4-folds. The intensities of the fluorescence spectra increase to 1.8- and 5.2-folds. Their photocurrent increases to 2- and 7-folds under the irradiation of a 405-nm laser. The LUMO energy levels move downward slightly from −3.89 to −3.90 and −3.92 eV, respectively. Our results indicate that as the carbon number increases, the carbon chain lengths in the ester structures increase, very slight effects produced on the energy levels of the fullerene dimers, but strongly contribute to their chemical activities and thus the photoelectronic efficiencies.

The absorption spectrum of Ti3+ in quartz is typical for that element in an octahedral site, except for the high oscillator strength of the band which indicates intensive charge transfer, most likely between a substitutional Ti4+ and an interstitial Ti3+. The biaxial anisotropy of the band is similar to that of octahedral Fe2+ in the same crystal, suggesting the same site for the Ti3+, an interstitial site at the intersection of the threefold axis with two twofold axes. The dynamic nature of the Ti and Fe ions is indicated when the crystal is subjected to X-irradiation and then to bleaching treatment with UV-light or heat. Ti(IV) ions are acceptors of electrons donated by Fe2+ during X-irradiation. This is indicated by increase of the 2.4 eV band intensity with decrease in the Fe2+ band intensities and appearance of Fe3+ charge transfer bands in the UV-region. Heat and UV-light treatment decrease the Fe3+ CT bands and increase the Fe2+ crystal-field bands along with decrease in the 2.4 eV band related to titanium.

4-hydroxy-3-methoxyphenyl-4-hydroxycoumarin chalcone (C19H14O6) was synthesized by the Claisen–Schmidt reaction with the condensation of 3-acetyl-4-hydroxycoumarin with 4-hydroxy-3-methoxybenzaldehyde (vanillin). The new compound was characterized by Fourier transform infrared microscopy, UV–vis 1H, and 13C NMR spectroscopy and its crystal structure was ab initio determined from laboratory X-ray powder diffraction data. The crystal structure is monoclinic with unit-cell parameters a = 14.3181(4), b = 8.040 71(9), c = 13.5524(3), β = 100.3559(13)°, V = 1534.84(6) Å3, and space group P21/c.

Nd-doped LaVO4 crystals with the concentration up to 0.94 at.% were successfully grown by the Czochralski method. X-ray powder diffraction measurement reveals that this crystal belongs to a monoclinic space group P21/n. Refractive indices of Nd:LaVO4 have been measured with two right angle prisms for the first time to our knowledge and show that they are anisotropic. Its absorption and fluorescence spectra are also investigated. With the Judd–Ofelt theory, the optical parameters calculated are Ω2 = 2.142 × 10−20 cm2, Ω4 = 3.704 × 10−20 cm2, and Ω6 = 2.948 × 10−20 cm2. By these parameters, the absorption oscillator strengths, line strengths, transition probabilities, fluorescence branch ratios, radiative lifetime, and integrated emission cross section are also derived and compared with familiar vanadates, which show that Nd:LaVO4 is a atypical material and has potential applications in the lasers, especially in the pulsed lasers.