Blue PL and EL emissions from Bi-activated binary oxide thin-film phosphors

The photoluminescent (PL) and electroluminescent (EL) characteristics in the thin films of various Bi-activated binary oxide phosphors have been investigated. La 2 O 3 :Bi, Gd 2 O 3 :Bi and Y 2 O 3 :Bi phosphor thin films were prepared on thick BaTiO 3 ceramic sheet substrates by r.f. magnetron sputtering depositions followed by postannealing. Intense blue PL emissions were observed from all Bi-activated binary oxide phosphor thin films postannealed at a high temperature. Blue, whitish blue-green or blue-green emissions were observed from thin-film electroluminescent (TFEL) devices fabricated with a La 2 O 3 :Bi, a Gd 2 O 3 :Bi or a Y 2 O 3 :Bi thin-film emitting layer, respectively. In addition, high luminance with good color purity in blue EL was obtained in a TFEL device using a La 2 O 3 :Bi thin film prepared under optimized conditions.