Regulating the broadband near-infrared emission of Eu2+-doped Ca3Sc2Si3O12 phosphors through constructing defect for diversified applications

Abstract

Near-infrared (NIR) emitting phosphors exhibit admirable photophysical performances which enable their promising application in various fields, whereas the development of a broad NIR emitting phosphors with high performance is still a challenge. Herein, series of Ca2.94Sc2-xSi3O12:0.06Eu2+ (Ca3Sc2-xSi3O12:Eu2+) garnet NIR emitting phosphors were designed and the defect engineering was used to regulate the luminescence properties. Upon 520 nm excitation, the resulting phosphors emit intense broad NIR emission peaking at 876 nm arising from Eu2+. Through decreasing Sc3+ content, the defect (i.e. Sc3+ vacancy) was formed and it can efficiently increase the luminescence characteristics of designed compounds, in which Ca3Sc1.9Si3O12:Eu2+ phosphor possess the strongest intensity. Moreover, based on density functional theory, theoretical calculation was performed to verify the existence of Sc3+ vacancy in studied samples. Furthermore, the fluorescence intensity and full-width at half maximum (FWHM) were all dependent on temperature. Through analyzing the temperature-dependent FWHM value, it was found that the maximum absolute and relative sensitivities were 42.61 % and 0.16 % K−1, respectively. Via utilizing the synthesized phosphors as NIR converters, a new NIR light-emitting diode (LED) was packaged and it presented potential applications in food detection, bioimaging, NIR solid-state lighting and night-vision. Our findings proposed an efficient strategy to manipulate the luminescence properties of NIR emitting phosphors via constructing defect so as to realize their vivid applications.