Pyrolytic synthesis of densely packed grown CdSe nanoparticles using a dual function octylamine for hybrid solar cells

We report here a well crystallized wurtzite phased CdSe nanocrystals by utilizing only octylamine ligand without the use of standard surfactants (TOPO, Fatty acids, Long chain alkyalmines, ODE) by a pyrolytic synthesis at 270 °C. The synthesized CdSe nanocrystals possess a diameter of ~6 nm with a band gap of 1.85 eV. Hybrid P3HT:CdSe heterojunction solar cells have been fabricated from the blends of the synthesized CdSe nanocrystals and poly (3-hexylthiophene) (P3HT) in a chloroform solvent which shows a maximum power conversion efficiency of 1.41%. However, standard CdSe quantum dot nanocrystals show a low conversion efficiency of 0.08% due to presence of a thick ligand shell. The enhanced efficiency can be attributed to the surface narrow size distribution (thin shell) and better optical properties; additionally it does not require post synthetic pyridine treatment. The details of morphological and optical properties of samples have been analyzed by TEM, XRD, UV-vis, PL, J-V and EQE techniques.