Down-shifting spectroscopic properties of Yb~(3+) doped BaGd_2ZnO_5 phosphors

摘要

Yb~(3+) doped BaGd_2ZnO_5 phosphor was synthesized via sol-gel method. X-ray diffraction, scanning electron microscopy and photoluminescence spectra were employed to characterize the as-obtained products. Upon 274 nm excitation, a single strong narrow-band emission from ~2F_(5/2) → ~2F_(7/2) of Yb~(3+) ion around 977 nm was obtained in Yb~(3+) doped BaGd_2ZnO_5 phosphor, which was well suited to efficient absorption in a silicon solar cell. After adding Ce~(3+) into Yb~(3+)-doped BaGd_2ZnO_5, the excitation spectra of samples monitored at 977 nm indicated that the excitation peaks were in the broad range from 230 nm to 400 nm, which covered ultraviolet and blue light with poor solar cell spectral response. Furthermore, Er~(3+) was introduced into Yb~(3+)-doped BaGd_2ZnO_5 phosphor to prove the high energy transfer efficiency from Gd~(3+) ion to Yb~(3+) ion by comparing it with that of Er~(3+) ion to Yb~(3+) ion. With access to broad-band absorption, narrow-band emission as well as high energy transfer efficiency, Ce~(3+), Yb~(3+) -codoped BaGd_2ZnO_5 may have potential applications in modifying the solar spectrum to enhance the efficiency of silicon solar cells.