scholarly journals Surface Plasmon Resonance Sensor of CO2 for Indoors and Outdoors

2021 ◽  
Vol 11 (15) ◽  
pp. 6869
Author(s):  
Francisco Pérez-Ocón ◽  
Antonio M. Pozo ◽  
Jorge Cortina ◽  
Ovidio Rabaza

The ability to detect CO2 with the smallest possible devices, equipped with alarms and having great precision, is vital for human life, whether indoors or outdoors. It is essential to know if we are being subjected to this gas to establish the level of ventilation in factories, houses, classrooms, etc., and to be protected against viruses or dangerous gas concentrations. Equally, when we are in the countryside, it is useful to be able to evaluate if the greenhouse effect, caused by this gas, is increasing. We propose a surface plasmon resonance (SPR) sensor for the measurement of CO2 concentrations taking into account that the refractive index of carbon dioxide depends on temperature, humidity, pressure, etc. With our sensor we can measure (in air) in any type of environment and concentration. Our sensor has a resolution of 5.15 × 10−5 RIU and a sensitivity of 19.4 RIU−1 for 400 ppm.

Biosensors ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 455
Author(s):  
Wei Du ◽  
Lucas Miller ◽  
Feng Zhao

A new waveguide-based surface plasmon resonance (SPR) sensor was proposed and investigated by numerical simulation. The sensor consists of a graphene cover layer, a gold (Au) thin film, and a silicon carbide (SiC) waveguide layer on a silicon dioxide/silicon (SiO2/Si) substrate. The large bandgap energy of SiC allows the sensor to operate in the visible and near-infrared wavelength ranges, which effectively reduces the light absorption in water to improve the sensitivity. The sensor was characterized by comparing the shift of the resonance wavelength peak with change of the refractive index (RI), which mimics the change of analyte concentration in the sensing medium. The study showed that in the RI range of 1.33~1.36, the sensitivity was improved when the graphene layers were increased. With 10 graphene layers, a sensitivity of 2810 nm/RIU (refractive index unit) was achieved, corresponding to a 39.1% improvement in sensitivity compared to the Au/SiC sensor without graphene. These results demonstrate that the graphene/Au/SiC waveguide SPR sensor has a promising use in portable biosensors for chemical and biological sensing applications, such as detection of water contaminations (RI = 1.33~1.34), hepatitis B virus (HBV), and glucose (RI = 1.34~1.35), and plasma and white blood cells (RI = 1.35~1.36) for human health and disease diagnosis.


2012 ◽  
Vol 84 (21) ◽  
pp. 9085-9088 ◽  
Author(s):  
Thomas Lang ◽  
Thomas Hirsch ◽  
Christoph Fenzl ◽  
Fabian Brandl ◽  
Otto S. Wolfbeis

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