Synthesis and Characterization of CdSe Quantum Dot via Pyrolysis of Organometalic Reagent

Charles Ahamefula Ubani¹, M. Y. Sulaiman², Z. Ibarahim¹, N. B. Ibrahim¹, M. Y. Othman³ 
(1. Pusat Pengajian Fizik Gunaan, Fakulti Sains dan Teknologi Universiti Kebangsaan Malaysia, 43600 Bangi, Malaysia;
2. Solar Energy Research InstituteUniversiti Kebangsaan Malaysia, 43600 Bangi, Malaysia;
3. Institute of Islam Hadari, Universiti Kebangsaan Malaysia, 43600 Bangi, Malaysia)

Abstract: We report a low cost and reproducible synthesis of cadmium selenide (CdSe) quantum dot (QD) via pyrolysis of organometallic reagent. The synthesis was performed in a fume-hood starting with the injection of one week old selenium precursor (organometallic source) into cadmium oxide (CdO) solution (pyrolyfic source) at 195°C to produce discrete homogeneous nucleation under slow growth. Differences in the injection time resulted to dissimilarity in the nanocrystal growth, shape and size. Oleic acid (OA) was used to protect the CdSe QD against oxidation and photon emission loss while organic ligand layer of trioctylphosphine (TOPO) was used to protect the QDs from agglomeration. The optical properties of the CdSe QD with size ranges between 2.09 and 4.90 nm were characterized using transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), energy-dispersive x-ray spectroscopy (EDX) optical photoluminescence (PL) and absorption spectroscopy (UV-vis). The peak-to-peak values, irregularities in the surface texture and the root-mean-square values of the surface roughness of the CdSe QDs were determined. The CdSe QDs were found to be stable under ambient temperature for about three months.

Key words: CdSe quantum dot; nanocrystals; photoluminescence; solar cell