Characterisation and Mechanoluminescence studies of Sr2MgSi2O7: Eu2+, Dy3+

Efficient Photopolymerization of Dental Resin Composites Using the Photoluminescent Long Afterglow of Sr2MgSi2O7:Eu2+,Dy3

Dental curing light with blue emission acts as the excitation source for the photopolymerization of the dental composite resin to achieve dental repairing. However, the current repair methods still suffer from a low monomer conversion degree and incomplete resin curing. In this study, novel dental resin composites (DRCs) were prepared by combining Sr2MgSi2O7:Eu2+,Dy3+ (SMSED), a photoluminescent material with a blue long afterglow, and dental resin composites. The curing depth, double bond conversion, elastic modulus, compressive strength, water absorption and solubility, and cytotoxicity were investigated systematically. The results suggest that adding 1 wt % SMSED to dental resin composites can maximize the curing depth and double bond conversion rate of DRCs and reduce its water absorption capacity without affecting the mechanical properties and biological toxicity. This work explores the practical applications of SMSED in dental resin composites, which provides an important reference for further improving the effect of dental caries repair.

Near White Light Emission and Concentration Quenching of Calcium Titanate Doped with Dysprosium (III) Phosphors

This paper reports the preparation of CaTiO₃ doped with various concentrations of Dysprosium (II) using solid state reaction technique. X-ray diffraction patterns of the sample were taken. Observed XRD pattern was matched using software match2!. The pattern was matched significantly with the crystallographic open database card (COD - 96-101-1212) which is a standard card for CaTiO₃. This matching exhibited that, the prepared sample is cubic in structure with space group P m - 3 m (221). Photoluminescence (PL) studies of the samples were also done. PL intensity was found increasing with increasing dopant concentration and maximum intensity was noted at 2.0 mol% concentration of Dy³⁺, thereafter concentration quenching occurred. Emission Peaks were centered at 483 nm (⁴F_9/2➔⁶H_15/2) and 576 nm (⁴F_9/2➔⁶H_13/2) respectively. For studying the concentration quenching, the critical distance for energy transfer and electric multipolar character were estimated. The value of multipolar character expressed that, the transition in emission spectra is a dipole - dipole (d-d) transition. Commission Internationale de l'Éclairage (CIE) coordinates was found as (0.36, 0.39), which is near to white light. Colour Correlated Temperature (CCT) was 4489 K which was indicative of cool appearance of the light emitted.