Proceedings of nanoGe Fall Meeting19 (NFM19)
Publication date: 18th July 2019
Two-dimensional lead sulfide (PbS) nanomaterials are of a great interest due to their tunable-optical activity in the near infrared (IR) spectral regime, attributed to the narrow band-gap energy ~0.41 eV and large Bohr radius ~ 20 nm. In addition, they have improved lateral conductivity surpassing their zero-dimensional counterparts due to lack of hopping events of charge carriers. In the present study, we introduce feasible synthesis approach towards the formation of PbS nano-sheets using colloidal chemistry. The lateral size and shape of the nanosheets were controlled by varying the ratio between fatty acid and phosphine ligands and adjusting the synthesis temperature during the growth of the nanosheets. This eventually altered the absorption band gab in the IR. Obtaining the mono-dispersity of nanosheets is a challenge in the current state of colloidal research. Controlling the unique size of the nanosheets is a demand for building up opto-electronic devices. The milestone of the current work is a success to obtain a stable well dispersed nanosheets with narrow size distribution. The driving force towards anisotropic growth into two dimensional assemblies, final shape and crystal structure is investigated using electron microscopy imaging, x-ray diffraction technique and Raman spectroscopy. Furthermore the research attempts are directed towards understanding the mechanism of formation and the role of ligands on the nanosheets evolution which can provide an insight for engineering the lateral PbS nanosheets, where the charge carriers have free motion enhancing the electronic conductivity. These engineered nanosheets may serve as an active layer material in opto-electronics devices.