Optimizing the Structure and Optical Properties of Lanthanum Aluminate Perovskite through Nb Doping.

This work involves the introduction of niobium oxide into lanthanum aluminate (LaAlO) via a conventional solid-state reaction technique to yield LaAlO:Nb (LaNbAlO) samples with Nb doping levels ranging from 0.00 to 0.25 mol%. This study presents a comprehensive investigation of the effects of niobium doping on the phase evolution, defect control, and reflectance of LaNbAlO powder. Powder X-ray diffraction (XRD) analysis confirms the perovskite structure in all powders, and XRD and transmission electron microscopy (TEM) reveal successful doping of Nb into LaNbAlO. The surface morphology was analyzed by scanning electron microscopy (SEM), and the results show that increasing the doping concentration of niobium leads to fewer microstructural defects. Oxygen vacancy defects in different compositions are analyzed at 300 K, and as the doping level increases, a clear trend of defect reduction is observed. Notably, LaNbAlO with 0.15 mol% Nb exhibits excellent reflectance properties, with a maximum infrared reflectance of 99.7%. This study shows that LaNbAlO powder materials have wide application potential in the field of high reflectivity coating materials due to their extremely low microstructural defects and oxygen vacancy defects.