Abstract

CdSe quantum dots were prepared via a colloidal route using an organic capping agent consist thiol group (SH). We explicitly calculated the exciton binding energy and we incorporate the exciton contribution then combined it with quantum confinement model and surface states to see its effect on photoluminescence. The results obtained by using MATLAB programming. Calculations took place at room temperature on small quantum dots (1 - 5 nm). In conclusion, our results are quite new and it effect some of the feature that has quite close correspondence with the experimental. The results are also in conformity with other theoretical and experimental investigations. This study shows the applications of photoluminescence spectrum in determination the size of nano particle, distribution of size and surface energy level of CdSe quantum dots.