PbS Cubes with Pyramidal Pits: An Example of Etching Growth

In this paper, we present the synthesis of PbS cubes with a hierarchical pyramidal pit on each face by a facile template-free solvothermal approach in the presence of cetyltrimethyl ammonium bromide (CTAB). In addition to anisotropic PbS cubes, we obtained an amount of PbS tapes. The growth mechanism of the cubes with pyramidal pits is discussed; the formation of the PbS hierarchal cross-sections should be attributed to the etching force of the base in the system. These structures might be model systems for understanding the growth process of anisotropic crystals and for fabricating optical devices.