title: Synthesis of ligand-selective ZnS nanocrystals exhibiting ligand-tunable fluorescence.
abstract: High-quality ZnS nanocrystals (NCs) of nearly identical size are synthesized using isomeric ligands, o-, m-, p-phenylenediamines (PDAs) that bind to the NC cores. The fluorescence emission from the NC is tunable according to the structure of the isomer. The measured fluorescence quantum yields (QYs) are 2-3 times higher for NCs that are passivated with isomeric PDA ligands than the fluorescence QY of NCs prepared at the absence of PDAs. The NC morphologies were studied by low-angle and wide-angle X-ray diffraction (XRD), and by transmission electron microscopy (TEM). The average correlating sizes were found to be 3.0+/-0.3, 3.7+/-0.30, and 3.0+/-0.5 nm for the NCs that were passivated with o-PDA, m-PDA, and p-PDA, respectively. The Fourier-transform infra-red (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) studies were carried out to investigate the shell structure and the interaction between the core and the shell. The adsorbed ligands were quantitatively analyzed by TGA. The structure, morphology, and optical properties of these PDA passivated NCs were compared with the NCs prepared in the absence of PDA.
authors: National Research Laboratory of Nano-Information Materials, Department of Polymer Science and Engineering, Pusan National University, Busan 609-735, South Korea.
authors: M Habib
authors: MH
authors: Ullah
authors: Bonghwan
authors: B
authors: Chon
authors: Taiha
authors: T
authors: Joo
authors: Minsoo
authors: M
authors: Son
authors: Il
authors: I
authors: Kim
authors: Chang-Sik
authors: CS
authors: Ha
mesh_terms: D005453:Fluorescence; D007536:Isomerism; D008024:Ligands; D015394:Molecular Structure; D049329:Nanostructures / Q000737:chemistry*; D010316:Particle Size; D010655:Phenylenediamines / Q000737:chemistry*; D013440:Sulfides / Q000138:chemical synthesis* / Q000737:chemistry; D013499:Surface Properties; D017967:Zinc Compounds / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D008024:Ligands; D010655:Phenylenediamines; D013440:Sulfides; D017967:Zinc Compounds; C031238:zinc sulfide