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• Gas sensor was prepared using 1.5 × 1 mm plane electrodes. • Light illumination improved the sensor's response to gases. • The response of the SmFeO 3 sensor under light to 30 ppm acetone was 29.228. • The SmFeO 3 sensor has a low working temperature of 120 °C. In this study, we prepared SmFeO 3 nanopowders by the sol–gel method. The planar electrode sensor (1.5 × 1 mm) based on SmFeO 3 nanopowder is responsive to methanol, ethanol, acetone, and other gases. Different wavelengths (470 nm, 420 nm, and 370 nm) of light illumination affect the sensor's response to gas. The response under light illumination (370 nm, 98 mW) at 120 °C to 30 ppm methanol, ethanol, and acetone were 26.41, 23.804, and 29.228, which were 2.0, 1.4, and 1.4 times higher than those in the dark, respectively. The planar electrode sensor can reduce optimum working temperature and reduce energy consumption, so it has great potential for application in real life. [ABSTRACT FROM AUTHOR]

The challenge encountered by the sensor in practical application is that the optimal working temperature is high, which will cause certain dangers in the work. Herein, we fabricated a p-p heterojunction composite LaFeO 3 /YFeO 3 planar electrode sensor for gas detection. The planar electrode sensor adopts the method of direct heating, which reduces the optimal working temperature of the sensor compared with the traditional side-heated alumina ceramic tube sensor. The optimal operating temperature of the LaFeO 3 /YFeO 3 (0.8:0.2) planar electrode sensor is 110 °C. In addition, we also performed multi-wavelength (470, 420, and 370 nm) light illumination experiments on the LaFeO 3 /YFeO 3 sensor to improve gas response. Under 370 nm light illumination, the response values of the LaFeO 3 /YFeO 3 (0.8:0.2) sensor to 30 ppm methanol, acetone, and ethanol were 166.82, 199.58, and 292.67, which were 1.19, 1.33, and 1.36 times than those in the dark. The lowest detection limits of the LaFeO 3 /YFeO 3 (0.8:0.2) sensor under 370 nm light illumination for methanol, acetone, and ethanol were 0.3, 0.8, and 0.2 ppm, respectively. Therefore, the LaFeO 3 /YFeO 3 (0.8:0.2) planar electrode sensor has the advantages of small size, low optimal operating temperature, low power consumption, high response value to volatile organic compounds gases, and high-cost performance for use in different gas environments. • The LaFeO 3 /YFeO 3 (a:b) materials were fabricated by the sol-gel method. • Gas sensor was prepared using 1.5 × 1 mm plane electrodes. • The sensors were tested under multi-wavelength light illumination. • The optimal operating temperature of LaFeO 3 /YFeO 3 (0.8:0.2) sensor was 110 °C. • Light illumination improved the sensor's response to VOCs gases. [ABSTRACT FROM AUTHOR]

The planar electrode sensors of the La 1−x Y x FeO 3 (x = 0, 0.2, 0.4, 0.6, 0.8, and 1) perovskite material were prepared for volatile organic compounds (VOCs) gas detection. The La 1−x Y x FeO 3 (x = 0.8) sensor has a higher gas response than La 1−x Y x FeO 3 (x = 0, 0.2, 0.4, 0.6, and 1) due to a higher surface adsorbed-oxygen content of the material. Light illumination improves the gas response of the La 0.2 Y 0.8 FeO 3 sensor to VOCs gases. A higher gas response of the La 0.2 Y 0.8 FeO 3 sensor was attained as the light-source wavelength was shortened. The gas responses of the La 0.2 Y 0.8 FeO 3 sensor under 370 nm light illumination at 100 °C to 5 ppm ethanol, methanol, acetone, and formaldehyde were 36.369, 32.352, 36.357, and 12.545, respectively. Additionally, at 110 °C, the response to 5 ppm acetylacetone was 35.94. In conclusion, the La 0.2 Y 0.8 FeO 3 planar electrode sensor has greater gas responses and lower operating temperature to VOCs gases. Therefore, the planar electrode sensor can reduce power consumption and be used in various locations with known gases. • The La 1−x Y x FeO 3 gas sensors were prepared using 1.5 × 1 mm plane electrodes. • The La 0.2 Y 0.8 FeO 3 sensor has high responses to VOCs under light illumination. • The plane electrode sensor has a low optimum working temperature of 100 °C. • Multi-wavelength light illumination can improve the gas response of sensor. [ABSTRACT FROM AUTHOR]