Low-temperature synthesis of transparent conducting La-doped BaSnO3via rejuvenation of the dried peroxo-precursor

Abstract

In this article, we develop a low-temperature route for the synthesis of the high figure-of-merit transparent conductor, La-doped BaSnO3. Towards this, we first study the evolution of the cubic perovskite phase of the undoped BaSnO3 during solution combustion synthesis. A peroxo/superoxo precursor synthesized via H2O2 assisted co-precipitation is employed as the oxidizing agent. Typically, precursor drying is detrimental to the low-temperature conversion of the precursor to crystalline BaSnO3. The synthesis procedure developed herein is agnostic to the altered precursor composition obtained under the particular drying conditions. This is achieved by re-solvation of the precursor with ethyl alcohol prior to the annealing. The added ethanol plays the role of fuel, enabling an exothermic reaction of the components of the mixture, providing the heat of reaction for conversion and crystal growth. Complete conversion of the precursor to phase-pure BaSnO3 with a three-fold increase in the crystallite size at lower temperatures is thus achieved. We then demonstrate the facile incorporation of lanthanum as a dopant through this method. The low-temperature synthesized lanthanum substituted BaSnO3 displays optical absorption in the NIR region corresponding to free carrier generation, and n-type conductivity.