Chemical deposition of PbS on a series of ω-functionalised self-assembled monolayers

Thin films of PbS were chemically deposited on a range of surfaces comprising self-assembled monolayers (SAMs) on Au and on the gold substrate itself. The influence of the monolayer terminal group on crystal growth was investigated, and a range of contrasting functionalities were employed: COOH, OH, NH2, SO3H and CH3. The kinetics of film growth was measured using surface plasmon spectroscopy, and the structure of the films was studied by scanning electron microscopy and transmission electron microscopy. The orientation of the crystals in the films was studied by electron diffraction for very thin films and by X-ray diffraction for thicker films. The experiments demonstrated that both the gold substrate and the SAM terminal group were effective in influencing the nucleation and growth rates of the PbS films, the size of deposited crystals and the final orientation of crystals in the films. The composition of the deposition solution was also demonstrated to have a marked effect on the final orientation of the crystals.