Size distribution of CdSe nanoparticles

The CdSe alloy is a popular material for compound semiconductors. Particles offer high fluorescence intensity, stability, and monochromatic properties. Thus, they are being actively studied as visible-to-ultraviolet light emitting materials, as display materials, and as medical/biochemical fluorescent markers or tracers.

Fluorescence emission spectra of CdSe nanoparticles vary depending on their size. Using the small-angle X-ray scattering (SAXS) method, it is possible to determine differences among particle sizes on the order of several nanometers.

Below is a photo of five types of sample synthesized using a micro-reactor and their fluorescence emission spectra.

sample synthesized
fluorescence emission spectra

The graphs below show the SAXS data and the results of a SAXS particle size distribution measurement. This figure shows changes in emission wavelength depending on the particle size and how the emission spectrum widths correspond to the extents of the particle size distributions.

SAXS dataresults of a SAXS particle size distribution measurement

Samples supplied by Associate Professor Takahisa Omata, Graduate School of Engineering, Osaka University; Dr. Hideaki Maeda and Dr. Hiroyuki Nakanura, Micro Kuukan Kagaku Labo, National Institute of Advanced Industrial Science and Technology.

The S-MAX3000 pinhole SAXS camera design is available with a choice of conventional or high brilliance X-ray sources. A 3-meter, fully evacuated camera length provides both high intensity and high resolution. Coupled with a fully integrated 2-dimensional multi-wire proportional counter, the system is capable of making highly sensitive measurements from both isotropic and anisotropic materials. A wide range of sample stage attachments provide maximum flexibility in controlling environmental sample conditions during measurement. Read more...