5TH International Congress on Technology - Engineering & Science - Kuala Lumpur - Malaysia (2018-02-01)

Preparation And Characterization Of Vitamin B Complex Infiltrated Oxidized Nanocrystalline Porous Silicon For Biosensor Application

Nanostructured porous silicon was fabricated by electrochemical etching method and infiltrated with vitamin B complex through the physical adsorption method. The unique optical properties of porous silicon lead to a perfect candidate for optical transducers exploiting photoluminescence effects, on exposure to the surrounding environment. The fabricated Vitamin B complex infiltrated oxidized porous silicon surfaces were characterized by employing Scaning Electron Microscopy, Fourier Transform Infrared spectroscopy, contact angle and photoluminescence techniques. The infiltration of folic acid into oxidized porous silicon was confirmed by scanning electron microscopy, which reveals that the surface looks like sponge-like structure. The pores are seen to get covered with the vitamins B complex. The porosity of vitamin B complex infiltrated OPS layer was found to be decreased, which is evident that the vitamin molecular attachments can significantly reduce the porosity. Further it was supported by fourier transform infrared spectral analysis, which shows that vitamin b complex infiltrated ops sample identified the appearance of the typical amide bands labeled amide I (1655 cm−1) and amide II (1550 cm−1). The infiltration of vitamin B complex molecule into OPS surface, which contains an amide contents, is evident by the low value of the contact angle measurement. The PL studies have been observed that the photoluminescence intensity of porous silicon decreased with the increasing vitamins concentration. The observed loss of PL intensity is due to the non-radiative recombination processes and also indicates that the spectral position of the PL peak in the OPS is affected. It confirms an obvious red shift in the vitamin B complex infiltrated OPS sample that because of the coupling of small organic molecules and results in an increase of the refractive index of OPS. The apparent red shift in the peak positions from 596 to 617 nm were accompanied by the decrease in the energy gap like 2.1 and 1.98 eV. A Stern–Volmer curve of the constructed optical biosensor was found to be 20-80 µM and the sensitivity was found to be o.45 nm/µM with the limit of detection of 22 nM.
Jeyakumaran Natarajan, Prithivikumaran Natarajan, Lawrence Boulsathiyanathan