Abstract
In this paper, a new method for pesticide detection based on porous silicon microcavities was proposed. First, the aptamer of acetamiprid was fixed in the functionalized porous silicon microcavity. Then, the complementary strand of the aptamer modified with graphene quantum dots was hybridized with the aptamer, and the effective refractive index of the porous silicon microcavity increased. When acetamiprid was added, it bound to the aptamer due to its stronger specificity. The aptamer separated from the complementary strand of the coupled graphene quantum dots and bound to acetamiprid, resulting in a decrease in the effective refractive index, and its central wavelength of reflection spectrum was blue shifted, and the blueshift increased with the increase of acetamiprid concentration. The relationship between the change in central wavelength and the concentration of acetamiprid was analysed, and the detection limit of acetamiprid was 151 nm.
Highlights
POROUS silicon has the advantages of a large specific surface area, good biocompatibility, and easy biological modification, and it can be used to fabricate various types of photonic devices; it has good application prospects in the field of sensors [1], [2]
The black curve is the reflection spectrum calculated by Porous silicon microcavity (PSM) theory, and the red curve is the reflection spectrum of the experimentally prepared sample that was detected by the reflection spectrometer
It can be seen from the figure that the defect peak of PSM device is just at 633 nm, which indicates that the PSM device is perfectly prepared
Summary
POROUS silicon has the advantages of a large specific surface area, good biocompatibility, and easy biological modification, and it can be used to fabricate various types of photonic devices; it has good application prospects in the field of sensors [1], [2]. Porous silicon microcavity (PSM) is the most widely used porous silicon material in biochemical detection due to their narrow defect peak [3]. Porous silicon optical sensors have two main types of detection mechanisms: The first type is based on the change in the refractive index, which is mainly used to identify changes in the reflection spectrum or angle spectrum to detect the substance being measured [4], [5]. It is equivalent to a defect layer with high transmittance and narrow half-width peak. Acetamiprid was detected based on the refractive index change of the PSMs
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