Synthesis and thermal annealing treatment of octylphosphonic acid-capped CdSe-tetrapod nanocrystals for bulk hetero-junction solar cell applications

• DOI: 10.1007/s11814-014-0300-3
• Publication Date: 2015-02-07T10:46:04Z
• Authors: Nguyen Tam Nguyen...; Kieu Thanh Trinh; Viet Thanh Hau Pham; Chang Duk Kim; Chinho Park
• Keywords: 01 natural sciences; 7. Clean energy; 0104 chemical sciences

CdSe-tetrapod nanocrystals (NCs) were synthesized by using octylphosphonic acid (OPA) as a capping ligand and cadmium oxide (CdO) as a cadmium precursor. The effects of thermal annealing in nitrogen (N2) environment on the chemical composition, morphology, crystal structure and optoelectronic properties of the CdSe-tetrapods have been investigated. Remarkable difference in the morphological and optoelectronic properties between as-synthesized and N2-annealed CdSe NCs was observed. The photoluminescence (PL) peak of N2-annealed CdSe NCs shifted to lower energy and UV-vis absorption spectra shifted to longer wavelength, indicating the size increase and improvement of the crystallinity of the CdSe tetrapods. The power conversion efficiency of bulk hetero-junction solar cells made with the annealed CdSe NCs showed higher value compared with the efficiency of cells made with as-synthesized CdSe NCs.