Towards spectroscopic reference material of semiconductor quantum dots and the size characterization using HRTEM

Abstract

Semiconductor nanocrystals (quantum dots) are a typical family of nanomaterials possessing unique optical properties, and have wide applications in biomedicine and optoelectronics. Reference materials for quantum dots will be important for quality control and industry applications, but require precise measurement research on the optical and geometrical characteristics. We describe here the initial effort towards developing RMs for CdSe quantum dots by charactering the optical properties. We also modify the TEM substrate to obtain better determination of quantum dot sizes by using carbon nanotube-oxidized graphene to replace conventional carbon film. Atomic resolution images of small sized quantum dots can be obtained with HRTEM. These results could help establish more precise relation between excitonic absorption peak position with particle size, and help wider utilization of quantum dots.