Synthesis of Fluorescent Nanomaterials and Their Applications to Solar Cells and Biosensors
Date Issued
2010
Date
2010
Author(s)
Lan, Guo-Yu
Abstract
Fluorescent nanomaterials are interesting for use in bioassays and solar cells, mainly because of their unique optical properties, including size-dependent emission wavelengths, narrow emission profiles, and photostability. This thesis focuses on preparation, characterization, and applications of water soluble semiconductor quantum dots (QDs) and fluorescent metallic nanoclusters (NCs). I developed a photo-assisted approach for the synthesis of ZnSe(S) QDs that fluoresce strongly and exhibit a narrow bandwidth. A photo-assisted method was applied to the synthesis of highly-water soluble ZnxHg1–xSeyS1–y QDs having emission ranging from blue to near-infrared (NIR) region. PL spectra, high-resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD) and/or X-ray photoelectron spectroscopy (XPS) were used to characterize the as-prepared nanomaterials. I also developed a simple heating approach to prepare various sizes of CdTe QDs, leading to increased energy conversion efficiency (2.02%) of QDSSCs. A simple and rapid approach was demonstrated for the preparation of highly fluorescent and biocompatible DNA-Cu/Ag NCs from AgNO3, Cu(NO3)2, and NaBH4 using single-strand DNA scaffolds. Electrospray ionization mass spectrometry (ESI-MS) and inductively coupled plasma mass spectrometry (ICP-MS) were employed to characterize the DNA-Cu/Ag NCs, revealing that each DNA-Cu/Ag NC contain two Ag and one Cu atoms. The DNA-Cu/Ag NCs provided great fluorescence (QY 51.2%). Based on the fact that Cu2+ ions induced fluorescence enhancement of the DNA-Ag NCs, I further developed a label-free, fluorescence turn-on, and homogeneous assay for the highly selective and sensitive (8 nM) detection of Cu2+ ions. I also used a specific DNA scaffold consisting of a fluorescent-based motif (C12) and a specific sequence (CCAGATACTCACCGG) that recognizes a gene of fumarylacetoacetate hydrolase to prepare functional DNA-stabilized Ag NCs. The as-prepared DNA-stabilized Ag NCs exhibited good sensitivity (14 nM) and selectivity against a single-base mismatch (DNAmmt) sequence.
Subjects
quantum dots
photo-assisted method
quantum dot-sensitized solar cell
fluorescent Ag(Cu/Ag) nanoclusters (NCs)
copper ions
DNA detection
single nucleotide polymorphisms (SNPs)
Type
thesis
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