Surface and spectral studies of Sm3+ doped Li4Ca(BO3)2 phosphors for white light emitting diodes

Highlights: • First time, the orange-red emitting Sm³⁺ doped L_i4Ca(BO₃)₂ phosphor was synthesized by using the combustion method. • XPS studies confirm the presence of all the possible elements in Li₄Ca(BO₃)₂:Sm³⁺ phosphor. • A new amber emitting phosphor for near UV-excited light emitting diodes is projected. Orange-red emitting Sm³⁺ doped Li₄Ca(BO₃)₂ phosphors synthesized by combustion method were investigated for the applications in white light-emitting diodes. The phase purity and photoluminescence performance of the Li₄Ca(BO₃)₂:Sm³⁺ phosphor were studied in detail using the powder X-ray diffraction technique, UV-VIS-NIR absorption and Photoluminescence measurements. X-ray photoelectron spectroscopy was used to study the surface chemical composition and the electronic states of the elements composing the phosphor. The synthesized phosphor showed good absorption in the near ultraviolet region and four emission peaks in the visible region at 567 nm, 603 nm, 650 nm and 714 nm due to the characteristic transitions of the Sm³⁺ ion, resulting orange-red light as predicted by Commission Internationale de l'Eclairage coordinates. The concentration quenching mechanism, bandgap, phosphorescence lifetime and quantum efficiency of Li₄Ca(BO₃)₂:Sm³⁺ phosphors have been investigated. The results indicate that the Li₄Ca(BO₃)₂:Sm³⁺ is a good candidate as a bright orange-red component for near UV-excited white light emitting diodes.