Fabrication of thin film sensors by spin coating using sol-gel LaCrO3 Perovskite material modified with transition metals for sensing environmental pollutants, greenhouse gases and relative humidity

• Main Authors: Prashant Bhimrao Koli, M.Sc. (Chemistry), SET, Kailas Haribhau Kapadnis, M.Sc. (Chemistry), Ph.D., Uday Gangadhar Deshpande, M.Sc. (Chemistry), Ph.D., Umesh Jagannath Tupe, M.Sc. (Electronics), SET, Sachin Girdhar Shinde, M.Sc. (Chemistry), SET, NET, GATE, Raju Shivaji Ingale, M.Sc. (Physics), SET
• Format: Article
• Language: English
• Published: Elsevier 2021-04-01
• Series: Environmental Challenges
• Subjects: Modified LaCrO3 sensor; Greenhouse gas sensor; BET; TEM; Relative humidity
• Online Access: http://www.sciencedirect.com/science/article/pii/S2667010021000226
• ISSN: 2667-0100

In this study, we are reporting the fabrications of undoped LaCrO3 and Ni2+, Fe3+, Co2+ modified LaCrO3 thin films by spin coating method using the sol-gels prepared for these thin film samples. The structural properties of the spin coated LaCrO3 thin films measured by X-ray diffractometer (XRD), which confirms the formation of orthorhombic LaCrO3 nanoparticles. The morphological properties of the prepared films were investigated by the ease of scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HR-TEM) where the orthorhombic and crystalline LaCrO3 nanoparticles were observed. Energy dispersive x-ray analysis (EDAX) was utilized for the determination of elemental composition. The prepared material was found be in perfect elemental composition. The surface area and BJH pore distribution was observed by Brunauer-Emmett-Teller (BET) analysis. The Ni2+, Fe3+, Co2+modified LaCrO3 thin film found with high surface area of 86.32 m2/g. Optical properties of both prepared materials investigated by ultraviolet differential reflectance spectroscopy (UV-DRS) to compare band gap energy of prepared sensors. It is observed that due to modification of transition metals, band gap energy of modified LaCrO3 sensor is found to be declined. The electrical properties were carried out to confirm semiconducting behaviour of LaCrO3 semiconductor. The thin films were subjected for gas sensing study of CO, CO2, NO2, LPG, toluene vapours and petrol vapours. The modified LaCrO3 sensor found to be highly sensitive for CO2, CO, and NO2 gases with response 82.14 (300 °C), 74.52 (200 °C) and 65.18% (150 °C) respectively. The relative humidity from 10 to 90% at 20 Hz found to be efficient for modified LaCrO3 sensor. In summary it can stated that transition metal doping successful to tune the band gap energy, porosity and surface area of modified LaCrO3 sensor. Due to this the sensor properties such as% response,% selectivity, response recovery, reusability and humidity sensing performance found to enhance for modified LaCrO3 sensor.