Influence of lattice distortions on the emission wavelengths of Y3+- and Gd3+-substituted Lu3Al5O12:Ce3+ phosphors

(Lu1-xYx)(2.94)Al5O12:0.06Ce(3+) (0=x= 1.00) and (Lu1-yGdy)(2.94)Al5O12:0.06Ce(3+) (0 = y = 0.75) phosphors are prepared by the sol_gel method. All the prepared phosphors are indexed as a cubic garnet crystal structure (Ia3d space group). The substitutions of Y3+ and Gd3+ for Lu3+ in the Lu3Al5O12:Ce3+ phosphors affect the environment of Ce3+ in the Lu(Ce)O-8 dodecahedron and photoluminescence properties. In this work, to study the influence of lattice distortions on the emission wavelengths of the Y3+- and Gd3+-substituted phosphors, the lattice distortion factors and maximum emission wavelengths as functions of Y3+ and Gd3+ concentrations are investigated. The Y3+ and Gd3+ substitutions induce the lattice distortion around the Ce3+ ions and shift the emission band of Ce3+ towards a red spectral region. Through the photoluminescence and crystallographic studies, we propose empirical equations between the lattice distortion factors (dY and dGd) and the maximum emission wavelengths (AY and AGd) for the Y3+- and Gd3+-substituted phosphors as ?(Y) = 1343.67d(Y) - 882.09 and ?(Gd) = 1703.79d(Gd) - 1260.74, respectively. The Y3+- and Gd3+-substituted phosphors show tunable emission wavelength, which may have potential applications in white light-emitting diodes.

Automated summary

(Lu1-xYx)(2.94)Al5O12:0.06Ce(3+) and (Lu1-yGdy)(2.94)Al5O12:0.06Ce(3+) phosphors were prepared by the sol-gel method with a cubic garnet crystal structure. The substitutions of Y3+ and Gd3+ for Lu3+ in the Lu3Al5O12:Ce3+ phosphors affected the environment of Ce3+ and photoluminescence properties. The lattice distortion factors and maximum emission wavelengths were investigated to study the influence of Y3+ and Gd3+ concentrations on the emission wavelengths of the substituted phosphors. The Y3+ and Gd3+ substitutions induced lattice distortion and shifted the emission band towards the red spectral region. Empirical equations between lattice distortion factors and maximum emission wavelengths were proposed. The Y3+ and Gd3+ substituted phosphors showed tunable emission wavelength for potential applications in white light-emitting diodes.