Influence of B2O3 Addition on the Properties of TiO2 Thick Film at Various Annealing Temperatures for Hydrogen Sensing

To increase the adhesion of thick film on a substrate, boron oxide (B2O3) was added to titanium dioxide (TiO2), and the change in the morphology, crystallinity and band gap of TiO2 thick film was investigated. TiO2 and TiO2-B2O3 pastes were prepared and deposited on the microscopic glass using screen-printing technique and then annealed under air at different temperatures of 400 degrees C, 450 degrees C and 500 degrees C for 30 min. The morphology, elemental composition, structure and absorption of the thick films were characterized using FESEM, EDX, XRD and UV-visible spectroscopy. The TiO2 and TiO2-B2O3 thick films were fabricated as gas sensors and exposed to 100-1000 ppm of hydrogen at an operating temperature of 300 degrees C. The results revealed that the addition of B2O3 increased the crystallinity of anatase phases and rutile phases in TiO2 as annealing temperature increased. The TiO2-B2O3(T500) gas sensor exhibited the highest response to various concentrations of hydrogen (100-1000 ppm) at an operating temperature of 300 degrees C.