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Ca2Al2SiO7:x.Sm3+ (x = 0.5, 1.0, 1.5, 2.0, 2.5, and 3.5 mol.%) (CAS:x.Sm3+) phosphors were synthesized by a solid-state reaction technique. The structure, photoluminescence properties and thermal stability of phosphors were investigated in detail. Results of X-ray diffraction show that CAS:x.Sm3+ materials have a single-phased tetragonal structure, and an expansion of the unit cell relates to the increasing of Sm3+ concentration. Photoluminescence study displayed that the CAS:x.Sm3+ phosphors reach the highest emission intensity at 1.5 mol.% Sm3+ and achieved the luminescence quenching phenomenon a higher concentration. The dominant interaction mechanism of the concentration quenching process is determined due to the dipole–dipole interaction, and the critical transfer distance (Rc) is 26.7 A. The temperature dependence of photoluminescence spectra indicates that the Ca2Al2SiO7:Sm3+ (1.5 mol.%) phosphor possess good thermal stability, and that the activation energy is around 0.12 eV (968 cm−1). Several characteristic vibrations in the 200–1000-cm−1 region were observed by Raman spectra, and the color chromaticity coordinates of the samples were also calculated and discussed.

In this study, the synthesis and luminescence properties (LP) of Al2O3-SiO2 glasses doped with different concentrations of Ce3+, namely, 0.05 mol.%, 0.1 mol.%, and 0.3 mol.% Ce3+, were investigated. The LP of the obtained samples were characterized by ultraviolet–visible absorption (UV–VIS) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy and photoluminescence (PL) spectroscopy. The results showed that the valence states of the cerium ions can be controlled by heating the synthesized glasses in hydrogen atmosphere leading to change their LP. The existence of the absorption band at about 295 nm and of a broad band spectrum with a maximum at 250 nm can be attributed to Ce3+ ion and the charge transfer band of Ce4+ ion, respectively. A broad emission at 366 nm observed under excitation of UV light at 310 nm originated from the well-known 4f–5d transition of Ce3+ ion. The role of Al3+ ions is also considered when glass samples were treated under the hydrogen atmosphere. It is revealed that the presence of aluminum ions enabled controlling the valence states of cerium via the formation of OH bonds that can reduce Ce4+ to Ce3+ ions in glass sample treated in reduced atmosphere. The increasing of PL peaks appeared during the treatment under hydrogen atmosphere at high temperature.

Aluminosilicate (AS) glasses doped with different Dy3+ concentrations were synthesized via sol–gel method. Absorption, photoluminescence spectra and lifetime of this material have been studied. From analytical results of absorption spectra, the Judd–Ofelt (JO) parameters of prepared samples have been determined. These JO parameters combined with photoluminescence spectra have been used to evaluate transition probabilities (AR), branching ratios (β) and the calculated oscillator strengths of AS:Dy3+ glasses. The radiative branching ratio of 4F9/2 → 6H13/2 transition has a minimum value at 62.2% for βR which predicts that this transition in AS:Dy3+ glasses can give rise to lasing action. JO parameters show that the Ω2 increases with the increasing of Dy3+ ion concentration due to the increased polarizability of the average coordination medium and decreased average symmetry.

Ternary CdSe x S1−x alloy quantum dots (QDs) were synthesized using a wet chemical method. Their morphology, particle size, structural, optical, and vibrational properties were investigated using transmission electron microscopy, x-ray diffraction, UV–Vis, fluorescence and Raman spectroscopy, respectively. The optical and vibrational properties of the QDs can be controlled by adjusting the Se/S molar ratio. The absorption and emission peaks shift to a longer wavelength range when increasing the Se content. The presence of two CdSe-like and CdS-like longitudinal optical phonon modes was observed. The dependencies of the optical and phonon modes on the Se content are discussed in detail.

Tellurite glass doped with different concentrations of Eu3+ ions has been prepared by the conventional melting process. Photoluminescence, Raman spectra, phonon side-band spectra, and Judd–Ofelt analysis were carried out. Some spectroscopic parameters were estimated to predict the luminescence efficiency of the materials. The energy transfer between the rare-earth ions was observed, and a model for its cross-relaxation was proposed and quantitatively estimated. The charged intrinsic defects in the form of nonbridging oxygen (NBO) were determined, and the energy transfer between NBO and rare-earth ions observed. The energy-transfer-induced Eu3+ photoluminescence enhancement in tellurite glass is studied.