Bi3+ enhanced red emission in Sr0.5Ca0.4MoO4:Eu3+ phosphor

• Bi3+–Eu3+ co-doped Sr0.5Ca0.4MoO4 red phosphors were synthesized.
• Doping Ca into SrMoO4:Eu3+ can enhance the emission intensity of Eu3+.
• Doping Bi3+ to Sr0.5Ca0.4MoO4:Eu0.13+ caused the host crystal orientation changed.
• Changing crystal orientation can adjust the excitation spectrum of Eu3+.
• The proposed explanation for enhancing in the 5D0 → 7F2 emission was given.

A series of Eu3+ single-doped Sr0.9−xCaxMoO4 and Bi3+–Eu3+ co-doped Sr0.5Ca0.4MoO4 red phosphors were prepared via a co-precipitation reaction. The X-ray diffraction patterns show that doping Bi3+ ions in Sr0.5Ca0.4MoO4:Eu0.13+ cause the host crystal orientation changed. The photoluminescent results show that the synthesized phosphor powders can be effectively excited at the wavelengths of 395 nm in ultraviolet light area and 464 nm in blue light area and 534 nm in green light area, and Strongly enhanced red emission of Eu3+ is obtained by adding Bi3+ instead of increasing the Eu3+ concentration. For a fixed Eu3+ concentration, there is an optimal Bi3+ concentration, at which the maximum luminescence intensity is achieved. The proposed explanation of these changes can not only be attributed to the energy transfer between Bi3+ and Eu3+ but also to the change in the symmetry of Eu3+ ions when doping Bi3+ into Sr0.5Ca0.4MoO4:Eu0.13+.