Palladium Nanoparticles Modified N-type Epitaxial Silicon Electrode for Photocurrent Detection of Ascorbic Acid

摘要

In this work, about 100 nm palladium layer was coated on the front surface of n-type epitaxial silicon wafer by vacuum evaporating and etched electrochemically in 0.1 M HF-HCl solution to form palladium nanoparticle modifying n-silicon electrode. Scanning electron microscope (SEM) and x-ray photoelectron spectroscopy (XPS) were used to characterize the morphology and composition of the modified electrode surface. The modified electrode has been used to constitute a novel photo-electrochemical sensor for the detection of ascorbic acid (AA) with a two-electrode cell in absence of reference electrode by photocurrent measurement at a zero bias. The photocurrent determination of AA shows two linear dynamic responses over the concentration range of 2 μM-42 μM and 82μM-642 uM with a detection limit of 2.0×10~(-6) M. Furthermore, this sensor demonstrated good stability, repeatability and selectivity remarkably.