Investigation of brightness and decay characteristics of YAG:Ce3+, Ca-α-Sialon:Eu2+ and CaAl12O19:Mn4+ phosphors incorporated with Ni-doped SnO2 particles

In this study, we investigated the enhancement in the optical and decay properties of three phosphors, Ce3+-doped yttrium aluminium garnet (YAG:Ce3+), Eu2+-doped yellow oxynitride phosphor (Ca-alpha-Sialon:Eu2+), Mn4+-doped aluminate-based phosphor (CaAl12O19:Mn4+), as a result of the interactions of the light-harvesting Ni-doped SnO2 additive. When the YAG:Ce3+ encapsulated in the presence of the nanoscale metal oxide in ethyl cellulose (EC) thin film, exhibited a 59% increase in its brightness as against its non-additive form. Similarly, when excited by 466 nm, the individual blends of Ca-alpha-Sialon:Eu2+ and CaAl12O19:Mn4+ phosphors with Ni-doped SnO2 particles demonstrated 65% and 93% improvement in the intensity values, respectively. Decay characteristics of the phosphors and their Ni-doped SnO2 blends were measured in microsecond and nanosecond time scales. When they are in close proximity in a polymeric matrix, the emission- and lifetime-based results have approved that Ni-doped SnO2 particles and phosphors act as donor and acceptor, respectively. Furthermore, the thermal stabilities, quantum efficiencies and CIE chromaticity coordinates of all phosphors and their blends with Ni-doped SnO2 additive were investigated. In parallel with the increase in emission-based intensities and decay time kinetics, we enhanced the internal quantum efficiencies to 94.1%, 86.2% and 80.4%, with the blending of Ni-doped SnO2 particles to YAG:Ce3+, Ca-alpha-Sialon:Eu2+, and CaAl12O19:Mn4+ phosphors, respectively. Notably, all of the phosphor composites along with additive indicated higher thermal stability in the temperature range of 303-503 K with respect to the additive-free forms. In the light of these results, the proposed composites can bring a new approach for the existing problems of yellow, orange, and red phosphors concerning the brightness and color rendering index and can be considered as potential candidates on LED technologies.

Automated summary

In this study, the addition of light-harvesting Ni-doped SnO2 particles was found to enhance the brightness and intensity values of YAG:Ce3+, Ca-alpha-Sialon:Eu2+, and CaAl12O19:Mn4+ phosphors, with measurements of decay characteristics in microsecond and nanosecond time scales. Results indicate that in a polymeric matrix, Ni-doped SnO2 particles and phosphors act as donor and acceptor, respectively.