In the journal, Sensors and Actuators: B. Chemical, researchers describe a simple sol-gel process used to create BiFeO3 (BFO) nanomaterials with a tetragonal deformed perovskite structure and a grain size of 50 to 100 nm.
Study: Enhanced H2S sensing performance of BiFeO3 based MEMS gas sensor with corona poling. Image Credit: P.V.R.Murty/Shutterstock.com
Is H2S a Harmful Gas?
H2S, a colorless and very hazardous gas, is easily created in human and industrial productions, such as petroleum operations, bioengineering, mining activities, drainage systems, and spoiled foodstuffs.
Even though the quantity of H2S is relatively low, it causes a significant hazard to human health and constitutes a danger to people.
Detecting and tracking minimal H2S in the environment is essential and recommended.
H2S can be identified using a variety of gas sensors, including electrolytic, optical, and metal oxide semiconductor (MOS)-based gas sensors.
Importance of Metal Oxide Semiconductor Sensors
Metal oxide semiconductor (MOS) detectors are perhaps the most promising candidate amongst sensing applications due to their low cost, fantastic performance, mobility, and ability to link many devices to a network.
Researchers have concentrated on developing temperature sensors based on various MOS for recognizing H2S, such as ZnO, SnO2, Co3O4, CuO, and others.
However, practical issues have yet to be addressed, such as sluggish response time, power dissipation, and a shortage of ppb-level detection systems.
Developing advanced gas sensors that can detect highly hazardous H2S remains a complex problem.
Effectiveness of Ferroelectric Materials
Ferromagnetic materials offer a wide variety of possible uses in multipurpose devices like sensors, storage systems, and inverters because they display the ferromagnetic optoelectronic impact, magnetic and dielectric connection, and complex physicochemical characteristics.
Ferroelectric oxides semiconductors, for example, have been a hot issue in ferromagnetic system projects because polarisation impacts the electrical characteristics of charge transfer.
Importance of BiFeO3 Sensors
Due to its polarizability, BiFeO3 (BFO), a ferromagnetic oxide semiconductor with a rhombohedral morphology, is one of the most researched ferroelectric materials.
BFO has been identified as a potential component of gas sensing applications for poisonous and dangerous gas detectors due to its low operating temperature and high specificity.
Previous investigations of BFO have been used to assess different volatile organic chemicals (VOC) such as methanol, alcohol, particulate matter, and others. However, the detection of H2S utilizing BFO-based sensors and the sensing mechanism associated with the ferroelectric polarisation effect is still unknown.
It is generally understood that the detection phenomena of MOS-based sensors primarily involve the electron transport between semiconductor oxides and reactive oxygen adsorption on the surface, resulting in a change in the existing phenomenon.
As a result, by controlling electron transmission, biosensor detection performance may be increased.
The domains configurations of BFO, as a ferromagnetic oxide layer, may be realigned by an external field, which can modify its ferroelectric polarisation and transport mobility.
All of the BFO-P0 diffraction patterns were strongly correlated with the rhombohedral deformed crystalline structure of BFO.
There were no additional noticeable spikes for contamination, showing that the highly pure BFO was effectively synthesized.
The UV-visible absorption spectrum was used to investigate the visual characteristics of materials related to the electrical framework and optical bandgap.
The absorption peaks edges of BFO-P0, BFO-P2, and BFO-P4 were identified in the spectrum about 550 nm owing to metal-to-metal transition.
Enhanced Biosensing Performance Results
The significant values of the three components to 1.2 ppm H2S showed an increasing maximum-decrease volcano kind pattern as the operational temperature was increased.
For all devices to monitor H2S, a temperature of 220 oC was chosen as the best-operating temperature.
The response values of the detectors increased as the poling electrostatic force increased, with the BFO-P4 sensor exhibiting the greatest response to 1.2 ppm H2S. This finding indicated that corona poling could help increase the H2S sensitivities of a BFO-based detector.
As the amount of H2S increases, so do the average values of the BFO-P0, BFO-P2, and BFO-P4 sensors.
The BFO-P4 sensor has a peak value in the H2S concentration range of 0.04 to 1.2 ppm, suggesting that it has outstanding reaction and recovery capacity.
To conclude, all through corona poling, the ferromagnetic zones of BFO seek to associate in the same orientation, which can boost the polarisation electrostatic potential of BFO.
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Xiaojie, Li., et al. (2021) Enhanced H2S sensing performance of BiFeO3 based MEMS gas sensor with corona poling. Sensors and Actuators: B. Chemical. vailable at: https://www.sciencedirect.com/science/article/pii/S0925400522001198