Zheng W.,CAS Fujian Institute of Research on the Structure of Matter |
Zheng W.,State Key Laboratory of Structural Chemistry Fuzhou |
Zhu H.,CAS Fujian Institute of Research on the Structure of Matter |
Zhu H.,State Key Laboratory of Structural Chemistry Fuzhou |
And 10 more authors.
Physical Chemistry Chemical Physics | Year: 2012
Quantum cutting (QC) of one visible photon into two infrared ones has been reported for the lanthanide ion couple (Tm 3+, Yb 3+) in a variety of host lattices. The mechanism responsible for QC was assumed to be a cooperative energy transfer (ET) process from Tm 3+ to two Yb 3+ ions, however, no solid evidence was presented. Herein we report visible-to-infrared QC for (Tm 3+, Yb 3+) in YPO 4 phosphors. The ET process from the excited 1G 4 level of Tm 3+ to Yb 3+ was investigated in detail by means of optical spectroscopy. By monitoring the steady-state photoluminescence (PL) and PL decay of the intermediate 3F 4 level of Tm 3+ as a function of the Yb 3+ concentration, we demonstrated the QC of one incident blue photon into one near-infrared emitting photon at 1004 nm from Yb 3+ and simultaneously into one mid-infrared emitting photon at 1791 nm from Tm 3+, rather than two emitting photons from Yb 3+. It was revealed that such visible-to-infrared QC was induced by phonon-assisted ET instead of cooperative ET as previously reported. This kind of QC phosphors may have potential as solar spectral converters to enhance the external quantum efficiency in multi-junction solar cells based on narrow band-gap semiconductors such as Ge, PbS or In 1-xGa xN. © 2012 the Owner Societies.