Ultraviolet to near-infrared downconversion in Yb3+-doped Sr2CeO4

✍ Scribed by Ru Zhou; Xiantao Wei; Yonghu Chen; Changkui Duan; Min Yin

• Publisher: John Wiley and Sons
• Year: 2011
• Tongue: English
• Weight: 482 KB
• Volume: 249
• Category: Article
• ISSN: 0370-1972
• DOI: 10.1002/pssb.201147431

✦ Synopsis

Abstract

Efficient blue–green emission is observed for Sr~2~CeO~4~ under ultraviolet excitation ranging from 250 to 400 nm and this is ascribed to the emission of the O^2−^–Ce^4+^ charge transfer (CT) states. Under the excitation of ultraviolet light in the broad absorption band, an intense near‐infrared (NIR) emission of Yb^3+^: ^2^F~5/2~ → ^2^F~7/2~ around 1 µm is observed for Yb^3+^‐doped Sr~2~CeO~4~. The Yb^3+^ concentration‐dependent luminescence properties and the lifetimes of both the visible CT emission and the NIR Yb^3+^ emission are investigated under the excitation of a 266‐nm pulsed laser beam. The fast decline of the lifetimes of the CT emission with the increasing Yb^3+^ concentration suggests efficient energy transfer from the host to Yb^3+^ ions. A cooperative energy transfer (CET) mechanism is proposed to explain the NIR downconversion process. The Sr~2~CeO~4~:Yb^3+^ phosphors can convert ultraviolet photons into NIR photons around 1 µm with a twofold increase in the photon number via CET, which has potential application in enhancing the photovoltaic conversion efficiency of silicon‐based solar cells.