Acta Phys. -Chim. Sin. ›› 2014, Vol. 30 ›› Issue (5): 994-1000.doi: 10.3866/PKU.WHXB201403131

• PHYSICAL CHEMISTRY OF MATERIALS • Previous Articles    

Synthesis of High Quality CdTe Quantum Dots in Aqueous Solution Using Multidentate Polymer Ligands under Microwave Irradiation

YUWEN Li-Hui, XUE Bing, WANG Lian-Hui   

  1. Institute of Advanced Materials, Nanjing University of Posts and Telecommunications, Nanjing 210023, P. R. China
  • Received:2013-12-20 Revised:2014-03-12 Published:2014-04-25
  • Contact: WANG Lian-Hui E-mail:iamlhwang@njupt.edu.cn
  • Supported by:

    The project was supported by the Major Research Plan of China (2012CB933301), National Natural Science Foundation of China (21204038, 81273409), PCSIRT of the Ministry of Education of China (IRT1148), Ph.D. Programs Foundation of Ministry of Education of China (20123223110007), Natural Science Foundation of Jiangsu Province, China (BK20130862), Natural Science Foundation of Universities from Jiangsu Province, China (13KJB150029), Open Research Fund of State Key Laboratory of Bioelectronics, Southeast University, China and Open Research Fund of State Key Laboratory of Coordination Chemistry, Nanjing University, China.

Abstract:

Quantum dots (QDs) have recently attracted considerable attention due to their unique optical properties and potential applications in biomedicine and optoelectronics. Although the organic synthesis of QDs is popular, aqueous synthesis is also very attractive not only for its low cost, low toxicity, and low reaction temperature, but also because the as-prepared QDs can be used directly for bio-related applications without the requirement for complicated surface modification processes. However, the monodentate ligands typically used for aqueous synthesis have limited binding ability, which can lead to weak colloidal stability and low photoluminescence. To solve these problems, we explored the use of multidentate thiol-containing polymer (PAASH) as a ligand to synthesize CdTe QDs and studied the influence of the ligand on the growth mechanism and photoluminescent properties of the QDs. PAA-SH was synthesized by conjugating cysteamine to poly(acrylic acid) (PAA) in the presence of dicyclohexylcarbodiimide. CdTe QDs of different sizes were prepared in aqueous solutions using PAA-SH as a ligand under microwave irradiation. The resulting PAA-SH-capped CdTe QDs show high photoluminescence quantum yield (PLQY) (up to 75%) without CdS shell coating, which is much better than the CdTe QDs synthesized using monodentate ligands. Furthermore, the hydrodynamic diameter of the PAA-SH-coated CdTe QDs is about 10 nm, and therefore much smaller than the polymer or SiO2 encapsulated QDs. In contrast, benefitting from cooperative binding effect of the multiple thiol groups and the high free energy for the ligand detachment from the QDs surface, PAA-SH-CdTe QDs show high storage stability.

Key words: Multidentate ligand, High quality, Quantum dots, Microwave aqueous synthesis

MSC2000: 

  • O649