A wet-chemical method for increasing the number of quantum dots (QDs) per unit surface area of TiO2 was developed. High density QD surface coating was induced by a surface charge controlled SILAR method, which led to a sixfold increase in photocurrent density from 2.15 mA cm(-2) to 15.03 mA cm(-2) in a QD-sensitized solar cell based on a Hg-doped PbS sensitized 2.4 μm-thick TiO2 film.