Highly sensitive mixed-potential-type NO2 sensor with YSZ processed using femtosecond laser direct writing technology

High performance mixed-potential-type NO2 sensors using yttria-stabilized zirconia (YSZ) electrolyte with NiCr2O4 sensing-electrode were fabricated. The femtosecond laser direct writing technology was used to process YSZ-substrate to construct structured surface. The results of scanning electron microscope (SEM) revealed that porous micron-sized groove was formed on the surface of YSZ-substrate by the radiation of 800-nm femtosecond laser. The sensor using processed YSZ-substrate outputted larger signal than the sensor using unprocessed YSZ-substrate in NO2 containing atmosphere at 800 °C which might be attributable to the enlargement of TPB (three-phase-boundary). In addition, the sensor maintained good response-recovery transients, repeatability and cross-sensitivity.