Generation of highly ordered nanoporous Sb–SnO2 thin films with enhanced ethanol sensing performance at low temperature

Abstract

Highly ordered nanoporous Sb-doped tin dioxide (Sb–SnO₂) thin films are crystallized by 120 °C post-synthetic hydrothermal treatment for gas sensing applications. The resulting thin films can be annealed, as desired, at temperatures of up to 600 °C for removing the templates and tuning the sensitivities without destroying the nanostructures. It is found that Sb–SnO₂ films doped with 8 wt% Sb can well satisfy the demands for high gas sensitivity at low operation temperature, e.g., a change of ∼30 times of electric resistance in response to 50 ppm ethanol is rapidly detected at temperatures as low as 100 °C. The structure, crystallinity, and composition of the ordered nanoporous Sb–SnO₂ thin films are characterized by HRTEM, FESEM, SAED, and STEM. The developed synthesis method represents a flexible route generally applicable for preparing nanoporous metal oxide crystalline films for applications including gas sensing, photocatalysis, and 3rd generation photovoltaics.