Novel two-dimensional lead sulfide quadrangular pyramid-aggregated arrays with self-supporting structure prepared at room temperature

Two dimensional (2D) self-supporting lead sulfide (PbS) arrays composed of ordered quadrangular nanopyramids were successfully fabricated through a convenient wet-chemical route at room temperature. The as-synthesized products were characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, UV-vis-NIR absorption and photoluminescence spectroscopy. The as-prepared highly ordered self-supporting superstructures are stable under ultrasonic conditions. A “template-mediated in situ growth” mechanism is proposed for the formation of 2D PbS superstructures. With the prolongation of reaction time, the morphology evolution of PbS is clearly observed, which could be changed from nanopyramid-aggregated arrays into nanocube-aggregated arrays at original position. The optical properties of PbS self-supporting superstructures are investigated in detail.