Abstract: The performance of lead sulfide quantum dot (QD) photovoltaic cells is improved by exposing a QD layer to a solution containing metal salts after the synthesis of the QDs is completed. The halide ions from the salt solution passivate surface lead (Pb) sites and alkali metal ions mend Pb vacancies. Metal cations and halide anions with small ionic radius have high probability of reaching QD surfaces to eliminate surface recombination sites. Compared to control devices fabricated using only a ligand exchange procedure without salt exposure, devices with metal salt treatment show increases in both the form factor and short circuit current of the PV cell. Some embodiments comprise a method for treatment of QDs with a salt solution and ligand exchange. Other embodiments comprise a photovoltaic cell having a QD layer treated with a salt solution and ligand exchange.

Abstract: The performance of lead sulfide quantum dot (QD) photovoltaic cells is improved by exposing a QD layer to a solution containing metal salts after the synthesis of the QDs is completed. The halide ions from the salt solution passivate surface lead (Pb) sites and alkali metal ions mend Pb vacancies. Metal cations and halide anions with small ionic radius have high probability of reaching QD surfaces to eliminate surface recombination sites. Compared to control devices fabricated using only a ligand exchange procedure without salt exposure, devices with metal salt treatment show increases in both the form factor and short circuit current of the PV cell. Some embodiments comprise a method for treatment of QDs with a salt solution and ligand exchange. Other embodiments comprise a photovoltaic cell having a QD layer treated with a salt solution and ligand exchange.