Eu^3+-doped Bi_2MoO_6 phosphors for highly sensitive and visible H_2S gas indicator material: optical and color properties, and gas sensing performance

Bi_2MoO_6:Eu^3+ phosphors were synthesized by a solid state reaction, and H_2S gas sensing performance was investigated. The Bi_2MoO_6:Eu^3+ phosphors showed an excellent red emission due to f-f transition of Eu^3+. Owing to the exposure to H_2S gas, the emission intensity of the phosphors dramatically decreased to 40% of the initial value. The body color of the phosphor changed from yellow-white to dark brown. The response of the Bi_2MoO_6:Eu^3+ phosphors for H_2S gas was started from 10 ppm, and the emission intensity exponentially decreased with increasing the concentration until 500 ppm.