Alternative green gap tuning via Dy3+ → Tb3+ energy transfer of double-doped germanate glass and the variation of the UV illumination wavelength
摘要
This work analyzes the influence of dysprosium (Dy3+) and terbium (Tb3+) trivalent rare-earth ions on germanate (86GeO2-14Na2O) glasses for multicolor lighting applications. After evaluation of the optical properties of single-doped Dy3+ and Tb3+ glasses by the means of photoluminescence emission, excitation and time-resolved spectroscopy, the energy transfer mechanism of a double-doped glass (Dy3+/Tb3+) was evaluated. The double-doped sample exhibited a dominant dipole–dipole interaction in the Dy3+ → Tb3+ energy transfer process, and low probability for the Tb3+ → Dy3+ reverse transfer process. This enables multiple emission and excitation bands as a result of the interaction of both trivalent ions. The energy transfer process Dy3+ → Tb3+ promotes different optical emissions within the green-yellow region as a function of the illumination source wavelength, enabling a correlated color temperature (CCT) tuning from 3767 to 6333 K using UV illumination wavelengths from 285 to 393 nm.