The development of nanostructured materials based on the self-assembly of simple constituents mediated by wet chemistry methods has been demonstrated to be an efficient and scalable bottom-up strategy. A particularly versatile approach is the use of spherical nanoparticles as building blocks. The existence of well-established synthesis methods to obtain monodisperse batches using a disparity of materials, combined with the inherent tendency of spheres to self-assemble into ordered 2D or 3D lattices, has resulted in a wealth of examples where, depending on the size, material, and surface structure and chemistry, nanoparticles have been employed to build photonic materials, functional
substrates, or biosensors, just to name a few.
Among the different methods that have been proposed to control the self-assembly of nanoparticles, Langmuir–Blodgett (LB) deposition stands out. Originally developed for the transfer of insoluble surfactants previously organized at the water/air interface, its use has been extended to the deposition of supramolecular entities and hard nanomaterials.
Structured thin films such as ordered monolayers or multilayers of nanoparticles are particularly well-suited to be prepared by the LB technique, and have been employed for the preparation of photonic materials or as templates to improve the tribological properties of substrates. Additionally, noble metal nanoparticles are widely used in biosensing thanks to their plasmon resonance that enhances scattered signals of adsorbed biomolecules. Raman spectroscopy is one of the most used for molecule identification and Surface-Enhanced Raman Scattering (SERS) leverages the plasmonic effects to increase by orders of magnitude the efficiency of an otherwise very inefficient process.