Efficient ultraviolet-blue to near-infrared downconversion in Bi-Dy-Yb-doped zeolites

Ultraviolet-blue to near-infrared (NIR) downconversion is investigated for the Dy3+?Yb3+ couple in zeolites by steady-state and time-resolved photoluminescence (PL) spectra, and PL excitation spectra. Upon excitation of the 4F9/2 level of Dy3+, NIR quantum cutting could occur through a two-step energy transfer from one Dy3+ ion to two neighbouring Yb3+ ions via an intermediate level. The energy transfer efficiency from the 4F9/2 level is estimated to be 42%, and the intrinsic PL quantum efficiency of Yb3+ emission reaches 54%. The findings may have potential application in enhancing the energy efficiency of silicon-based solar cells.