Structures and optical properties of CdSe nano flakes synthesized by an elemental direct reaction method

CdSe nano flakes have been synthesized through using the selenium powder and cadmium foil in the ethylenediamine by an elemental direct reaction method. These high-quality CdSe nano flakes, being approximately perpendicular to the cadmium foil substrate, show the hexagonal structure and are characterized with the networking structures. According to Kubelka-Munk method, band gap of CdSe nano flakes can be estimated to be similar to 2.44 eV. Multi-peak emissions under the excitation of 325 nm can be observed at room temperature. From green to red, four emissions can be fitted and attributed to the transition of band gap, selenium vacancies, interstitial cadmium, and the surface defects associated with oxygen, respectively. Investigation of multi-peak emission origins as well as understanding and regulating of defect states are helpful for CdSe nano flakes to apply in the field of the optoelectronic devices.

Automated summary

This study synthesized high-quality CdSe nano flakes with a hexagonal structure and networking structures using an elemental direct reaction method. The band gap of CdSe nano flakes was estimated to be approximately 2.44 eV using the Kubelka-Munk method. Multi-peak emissions were observed at room temperature under the excitation of 325 nm, which were attributed to the transition of band gap, selenium vacancies, interstitial cadmium, and surface defects associated with oxygen. Understanding and regulating the defect states are crucial for the application of CdSe nano flakes in optoelectronic devices.