PbS Quantum Dots with Inorganic Ligands: Physical Modeling of the Charge and Excitation Transport in Photovoltaic Cells

In photovoltaic cells based on PbS colloidal quantum dot (CQD) solids, the photoconductivity and efficiency for PbS CQDs with inorganic atomic ligands of tetrabutylammonium iodide (TBAI) are reasonably larger than those for PbS CQDs with molecular ligands of the same length. The TBAI ligands can act as electron-transporting sites and contribute to the increase in mobility. The developed simple model allows the maximum efficiency of a CQD solar cell to be determined, which can be achieved by eliminating the recombination losses of charge carriers. Both experimental data and theoretical modeling testify in favor of the hopping nature of the electron transport in CQD-solids.