Huge enhancement of Sm2+ emission via Eu2+ energy transfer in a SrB4O7 pressure sensor†
Taking advantage of the excellent pressure-sensing properties of the Sm2+ ion in the SrB4O7 crystal, we demonstrate an enormous enhancement of about 60 times in the emission intensity of Sm2+ ions when Eu2+ ions are also incorporated into the crystalline structure. This enhancement is induced by the energy transfer from Eu2+ to Sm2+ ions. The spectral position of the ultra-narrow and most intense 5D0 → 7F0 emission line in the material was correlated with pressure and successfully calibrated up to about 58 GPa. The material exhibits favorable pressure-sensing features, i.e. dλ/dp ≈ 0.29 nm GPa−1, negligible temperature-dependent shift, narrow and well-separated emission lines, and a strong luminescence signal. The samples also exhibit multicolor tunable luminescence from orange-red to amaranth, and to warm-white light, depending on the excitation wavelength used and dopant content in the matrix, allowing their potential application in white light emitting diode (LED) devices.