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Lin L.,Fujian Normal University | Lin L.,Fujian Provincial Key Laboratory of Quantum Manipulation | Lin H.,Fujian Normal University | Wang Z.,Fujian Normal University | And 8 more authors.
Optical Materials | Year: 2014

A new kind of quantum-cutting (QC) phosphor KYF4:Tb 3+,Yb3+ was prepared by the sol-gel method by using trifluoroacetic acid as a fluorine source. Tb3+-doped samples represent high quenching concentration as 15%. The near-infrared fluorescence spectra of Tb3+&Yb3+ co-doped samples with high Tb3+ concentration (15%) indicate that QC can occur under different excitations of Tb3+, and the 7F6 → 5D3 excitation (∼374 nm) is more effective than 7F6 → 5D4 excitation (∼483 nm). Through the lifetime measurement, the maximum of QC efficiency (ηQE) under 7F6 → 5D 4 and 7F6 → 5D3 excitations are calculated as 161% and 150%, respectively. The results all above infer that this phosphor can make use of high-energy photons of several wavelengths and may raise the conversion efficiency of solar cells greatly. © 2014 Elsevier B.V. All rights reserved.

Yang R.,Fujian Normal University | Yang R.,Foctek Photonics Inc. | Liu J.,Fujian Normal University | Liu J.,Fujian Provincial Key Laboratory of Quantum Manipulation | And 6 more authors.
Solar Energy | Year: 2016

Multilayer solar selective absorbing coatings of Cu/Ti/SiO2/Ti/TiO2/SiO2 were designed first and then deposited on quartz substrates using the magnetron sputtering method. The thicknesses of the individual layers were optimized to achieve high solar absorptance, while the colors were designed with the TFCalc optical design software. The colors of the coatings including purple, blue, blue green, yellow green and orange yellow were prepared based on the designed parameter. The colored solar selective absorbing coatings exhibit solar absorptance higher than 0.95 and thermal emissivity lower than 0.09 at 80°C. Furthermore, the thermal stability of the Cu/Ti/SiO2/Ti/TiO2/SiO2 coatings was studied by annealing at high temperature in vacuum and in air for 2h. The X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy and spectrophotometry were used to characterize properties of the coatings. The results showed that the multilayer solar selective absorbing coatings were thermally stable at 450°C in vacuum and 300°C in air for 2 h, which may provide an instruction to design and fabricate high performance colored solar selective absorbing coatings. © 2015 Elsevier Ltd.

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