Fig. 4. A schematic diagram illustrating the key processes of silver sulfide formation (modified from Saunders and Burke³¹).

The formation of silver sulfide crystals initiates with the flocculation of silver sulfide nanoparticles to aggregates and microparticles, followed by an intermediate product of silver sulfide dendrites through self-assembly, oriented attachment of microparticles. Infilling the spaces between the branches of the dendrites with nanoscale to microscale particles and further reorganizing these particles that ultimately form silver sulfide with defined crystal shapes.