Entropy-enthalpy interactions and optical properties of non-equiatomic multicomponent rare-earth oxides

The multicomponent oxides (Ce1/2Zr1/2)(1-x)(La1/3Y1/3Gd1/3)(x)O2-sigma with different elements ratio (x = 0.3, 0.45, 0.6, 0.75, 0.9; abbreviated as CZLYGx) were prepared by co-precipitation method. XRD patterns shows that the compostion with x = 0.9 exhibits mixing crystal structure of Fm-3 m and Ia-3 phases, while the others possess single-phase fluorite structures. Transmission electron microscopy shows that nanoparticles of CZLYG90 with a particle size of about 34 nm were synthesized. The competitive relationship between entropy and enthalpy are analyzed, low mixing enthalpy and high configurational entropy benefit the stabilization of single-phase multicomponent oxide. The direct band gap value of CZLYGx increases from 3.51 eV to 3.99 eV with x increasing, which exhibits promising candidate as an optical material.

Automated summary

Multicomponent oxides (Ce1/2Zr1/2)(1-x)(La1/3Y1/3Gd1/3)(x)O2-σ with different elements ratio (x = 0.3, 0.45, 0.6, 0.75, 0.9; CZLYGx) were successfully prepared by co-precipitation method. XRD patterns revealed that CZLYG90 exhibited a mixed crystal structure, while the others had single-phase fluorite structures. TEM analysis showed that CZLYG90 nanoparticles had a particle size of about 34 nm. The competitive relationship between entropy and enthalpy favored the stabilization of single-phase multicomponent oxide. The direct band gap value of CZLYGx increased with x, making it a potential optical material.