EAPSI: Synthesis of Thiolated Carboranes for Self-Assembled Monolayers on a Dy-doped CdO Surface

Khamh Hniang, Raleigh NC

Investigators

Abstract

This project aims to synthesize thiolated carboranes, organic molecules that are stable in water and extreme heat. These organic molecules will be attached to a plasmonic active material - cadmium oxide doped with dysprosium (CdO:Dy) - to protect it from being soluble in water and acidic solutions. CdO:Dy was recently reported as the first semiconductor that can host surface plasmons in the mid-infrared region as well as being an ideal material for mid-infrared biosensor chips. Investigation regarding whether or not the infrared vibration of these organic molecules can be detected when attached on CdO:Dy using Surface Plasmon Resonance (SPR) spectrometry will be performed in addition to exploring the possibility of using CdO:Dy as a biosensor chip. This project will be conducted at Zhejiang University in China with Professor Simon Duttwyler, an expert in carboranes synthesis. This work will lead to development of a sensitive mid-IR biosensor that can be used in drug discovery and also in small molecule detection for scientific research. A recently reported plasmonic active material, dysprosium doped cadmium oxide (CdO:Dy) possesses extreme peak of mobility and tunable carrier concentration giving rise to Surface Plasmon Resonance across the mid-IR range. Though CdO:Dy is an ideal mid-IR material for a biosensor due to its spectrally narrow and sharp plasmonic band, its solubility in water and instability in acidic solution pose many challenges experimentally. To overcome these obstacles, an objective of this EAPSI project aims to synthesize extremely hydrophobic and thermally stable molecules, thiolated carboranes, that will not only protect CdO substrate from (acidic) solutions, but also permit subsequent detection of these molecules through Surface Plasmon Resonance (SPR) spectroscopy; this will also facilitate the simultaneous investigation of potentially using CdO:Dy as a biosensor. Furthermore, thiolated carboranes will be deposited on CdO:Dy substrate using self-assembled monolayer, furthering the fundamental understanding of surface chemistry between Dy-doped CdO surface and organic molecules. This award under the East Asia and Pacific Summer Institutes program supports summer research by a U.S. graduate student and is jointly funded by NSF and the Chinese Ministry of Science and Technology.