The enhanced current density of the quantum dots solar cells based on CdSe:Mn2+ crystalline

Abstract

In this work, the pure CdSe and Mn-doped CdSe quantum dots were synthesized by Successive ionic layer absorption and reaction method for the high performance of quantum dots sensitized solar cells. Relevant molar concentrations of Mn(CH3COO)2.2H2O were changed at 0.1 mM, 0.2 mM, 0.3 mM, 0.4 mM, and 0.5 mM as mixing with Cd(CH3COO)2.2H2O anion source corresponding to x represent for the Mn2+-doped molar concentration. As a result, the quantum dots Solar cells were successfully prepared with the enhanced short current density from 7.63 mA/cm2 to 18.99 mA/cm2 for Mn2+ ions doped on CdSe nanoparticle corresponding to the enhanced efficiency of quantum dots solar cells from 1.64% for pure CdSe nanocrystal to 3.77% for Mn2+ ions doped on pure CdSe nanoparticle. Actually, Mn2+ dopant rises in the conduction band of pure CdSe nanocrystal, reduces recombination, enhances the efficiency of high harvesting, improve the charge transfer and collection. In addition, Mn2+ dopant can rise in the conduction band levels of pure CdSe nanocrystal, which leads to reduce the charge recombination, enhances the light-harvesting efficiency and improve the charge diffusion and collection. Correspondingly, the photoluminescence decay and Electrochemical Impedance Spectra were carried to determine the lifetime of excited electrons and dynamic resistances in QDSSCs.