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Ultraviolet to near‐infrared downconversion in Yb 3+ ‐doped Sr 2 CeO 4
Author(s) -
Zhou Ru,
Wei Xiantao,
Chen Yonghu,
Duan Changkui,
Yin Min
Publication year - 2012
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201147431
Subject(s) - ultraviolet , phosphor , materials science , doping , ytterbium , excitation , infrared , optoelectronics , ion , absorption (acoustics) , photon , luminescence , optics , chemistry , physics , organic chemistry , quantum mechanics , composite material
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.