Investigation of the Optical Properties of CdSe/ZnS Core/Shell Quantum Dot Embedded in an MEH-PPV Polymer Matrix

In this work, the role of poly[2-methoxy-5-(2-ethyl-hexyloxy)-1,4-phenylene-vinylene] MEH-PPV) as conducting polymer on the optical properties of the composite CdSe/ZnS core-shell quantum dots has been investigated. The optical properties of MEH-PPV polymer coated CdSe/ZnS composites are found to be dependent on the size of the quantum dot. A smaller CdSe quantum dot ensures a high exciton energy and smaller radiative lifetime. We found that the radiative lifetime in CdSe/ZnS embedded in MEH-PPV polymeric matrix is higher than that in CdSe/ZnS core-shell quantum dot. We also investigate the temperature dependence of the radiative lifetime over a temperature range from 100K to 300K; the temperature dependence of the radiative lifetime follows a quasi-exponential law. Consequently, the increasing temperature reduces the optical gap of MEH-PPV(CdSe/ZnS) polymer-CSQD. We found that the greater radiative lifetime corresponded to the larger values of temperatures.