SrB4O7:Pr3+中Pr3+的发光性质

Abstract

本研究报道pr3+在SrB4O7中的发光性质,在SrB4O7中Pr3+离子的4f5d能态高于1So能级,因此,在207 nm UV光激发下,Pr3+能够把所吸收的一个高能量的UV光子转换为两个可见光子的发射(光子倍增);在此氧化物基质中的光子倍增主要是由于阳离子处于弱的晶体场格位之中;由于与稀土离子弱联结相关的声子振动频率低(hωmax～1200 cm-1),因此还能观察到从3Po能级向低能级的跃迁.第一个光子的发射由1So→G4(313 nm),1So→1D2(338nm)和1So→1I6(405 nm)的辐射跃迁组成;第二个光子的发射由3P0和1D2能级向低能级的辐射跃迁组成[3Po→(3HJ,3FJ)和1D2→(3H4,3H5)].

The luminescent property of Pr3+ in SrB4O7 is reported. The energy level of Pr3+ 4f5d in SrB4O7 lies above the S-1(o) state, so under UV light excitation at 207 mn, cascade emission of Pr3+ occurs from the S-1(0) state in SrB4O7: Pr3+ (x = 0.0050) of which converts a single UV photon of high energy into two visible photons. The cascade emission observed with this oxide matrix is largely due to the weak crystal field on the cation sites. Analysis of the vibrational coupling indicates that the radiative transition from the P-3(0) state is related to the low photon frequency of the borate groups ( BO4) bonded to the Sr2+ ( or Pr3+) ions (h omega (max) = similar to 1200 cm(-1)). The S-1(0)--> (1)G(4)(313 nm), S-1(0)-->D-1(2)(338 nm) and S-1(0)--> I-6(405 nm) transitions are responsible for the first photon emission. The second photon emission originates from the transitions from the intermediate energy levels (P-3(0) and D-1(2)) to the lower energy levels [P-3(0)-->(H-3(J), F-3(J)) and D-1(2)-->(H-3(4), H-3(5))].