CdSe NCs consist of an inorganic core that is surrounded by a layer of different organic ligands such as fatty or long chained acids (e.g. Oleic Acid OA), alkyl phosphines (TOP). These capping molecules are responsible for stable colloidal solutions of CdSe NCs, preventing irreversible aggregation, coagulation and fusion of the NCs due to Van der Waals interaction. Fig.1.shows the FTIR transmittance spectra of CdSe NCs, Oleic Acid. For CdSe NCs, the spectra exhibits well defined main peaks: doublet band, i.e. 2857.4, 2927cm-1 corresponding to CH2 stretching (sp3) and νas (CH3) 2954.1 cm-1, which might be the surface termination of these NCs by functional groups [1]. The basic feature of the spectrum is a broad absorption band at 25003500cm-1, which takes place due to the OH bond of the carboxyl group of oleic acid. Two sharp peaks at 2924-2854 cm-1 as described, νas (CH2) − 2927 cm-1 ,νs (CH2) – 2857,4 cm- 1. Strong peak at 1707,8 cm-1 belong to C = O and the band at 1285 cm-1 corresponds to C-O of pure OA. Planar and nonplanar OH groups appear in the spectrum of OA at 1462 cm-1 and 937 cm-1. In the study of the spectrum of nanoparticles CdSe, we observe that the absorption band at 1707,8 cm-1 (OA) attributable to the stretching vibrations of carbonyl group splitting in two new characteristic bands νas( COO) at 1537 cm-1 and νs( COO) at 1417 cm-1, respectively. This suggests that the carboxyl group of oleic acid not only adsorbed on the surface of CdSe NCs, and is coordinated by two oxygen atoms symmetrically seems to cadmium. Flexible organic molecules aliphatic or phosphine ligands provide repulsive interaction between the NCs, thus preventing aggregation[2]. The C-P stretching peaks of TOP at 1093.1, 1048.7 cm-1 are not observed in CdSe NCs spectrum. The band at 722 cm-1 corresponds to CH2 vibration mode. However, the peak at 1435.5 cm-1 possibly originates from the asymmetric in-plane symmetric rocking mode of terminal methyl group of TOP. From this data, it should be also confirmed that the TOP is capping as well the CdSe surface [1]. On the basis of the FTIR data, the surface of the CdSe NCs is mainly coated with oleic acid ligand. Flexible organic molecules provide repulsive interactions between the NCs in solvents, thus preventing aggregation [3].