In previous studies conducted by our laboratory, nanoscale titanium dioxide (TiO₂) was selected as a solid-state substrate, forming a thin-film structure for organic sensor adsorption. The detection results showed the system's reasonable specificity and sensitivity toward silver ions (Ag⁺). However, the detection mechanism was not due to chelation or chemical reactions between the organic sensor and silver ions but rather stemmed from the intrinsic properties of titanium dioxide. When nano-TiO₂ absorbs light at specific wavelengths, valence band electrons are excited to the conduction band, reducing Ag⁺ to silver atoms, ultimately causing a color change in the thin film. In this process, the organic sensor only enhances visible light absorption, meaning the solid-state sensor's application is limited to silver ion detection. To expand the detection capability of the solid-state sensor to other metal ions, this study aims to replace nano-TiO₂ with nano-silicon dioxide (SiO₂). Compared to TiO₂, SiO₂ has a larger band gap, effectively suppressing its ability to reduce Ag⁺. This modification is expected to enable the organic sensor to interact with metal ions through chelation or chemical reactions, leading to structural changes in the molecules and measurable shifts in the absorption spectrum, thereby making quantitative analysis feasible. The main tasks of this study include fabricating nano-SiO₂ thin films and adsorbing the laboratory-developed organic sensor onto the films. Subsequently, a series of tests will be conducted, including analyzing the absorption range of the solid-state thin film, detection limits, interference from other ions, and the detection of actual water samples. Additionally, a calibration curve for the solid-state sensor will be established to provide a method for future quantification of heavy metal ions.

The primary recruitment sources are Vietnam, Japan, or other Asian countries. The recruitment period is from April 1 to October 30. Participants must conduct at least two months of research in the laboratory. A monthly stipend of 15,000 NTD per person will be provided. The university can assist in arranging accommodation; however, participants must cover the rent themselves and also manage their own meals.