Synthesis and luminescence characterization of aqueous stable Sr3MgSi2O8: Eu2+, Dy3+ long afterglow nanophosphor for low light illumination

Sunlight rechargeable and blue light-emitting (∼460 ​nm) silicate based Sr 3 MgSi 2 O 8 :Eu 2+ , Dy 3+ afterglow phosphor was synthesised via the facile co-precipitation method with an afterglow of >30 ​min. Detailed investigation on structural, morphological, thermal and optical characteristics of the as-prepared samples were done. XRD confirms the existence of Sr 3 MgSi 2 O 8 phase along with an additional phase of β-Sr 2 SiO 4 with crystallite size of ∼24 ​nm. No enthalpy change was observed in the sample beyond a temperature of 600 ​°C temperature as studied from Differential Scanning Calorimetry (DSC). Remarkably, excitation spectra of Sr 3 MgSi 2 O 8 :Eu 2+ , Dy 3+ was found overlap with UV-B and UV -A of solar spectrum received on the earth surface. Thus, as synthesised phosphor can be readily excitable by sunlight. Interestingly, emission intensity of the sample was found to persists more than 80% of its initial value even at high temperature of 100 ​°C. Commission Internationale de l'éclairage (CIE) color coordinates of Sr 3 MgSi 2 O 8 :Eu 2+ , Dy 3+ were calculated to be (0.15, 0.05) and were found to be close to standard National Television Standard Committee (NTSC) coordinates for blue light with a color purity of 95%. Real time demonstration of the aqueous stability of the Long Afterglow Phosphor (LAP) was also studied and the solution was found to be stable on a time scale of two months. Thus, as prepared Sr 3 MgSi 2 O 8 :Eu 2+ , Dy 3+ are a potential candidate for waterborne coatings, water-based paints and security inks. • Sr 3 MgSi 2 O 8 : Eu 2+ , Dy 3+ was found to be sunlight rechargeable and blue-emitting (∼460 ​nm) long afterglow phosphor. • Phosphor was found to exhibit excellent thermal stability with its emission intensity of 80% at a temperature of 100 ​°C. • Real-time experiments were done to study the aqueous stability of the as-prepared phosphor. • Owing to high thermal and aqueous stability phosphor is a potential candidate for outdoor waterborne coatings, paints and inks. • Energy transfer between activator ions was found to be multipolar interactions between dopant ions.