Layer-by-layer assembled photocatalysts for environmental remediation and solar energy conversion

The past decades have witnessed great research efforts based on nanotechnology and molecular engineering for the development of photo-induced devices, aiming at conversion of solar energy into electricity and fuels as well as the use of solar light for environmental remediation. The main challenge of this exciting field is to find suitable ways of assembling different materials into a single platform while making them capable of performing specific tasks, such as light-harvesting, charge transport or catalysis. In this scenario, layer-by-layer (LbL) thin film deposition appears a very promising technique, since it provides an unprecedented control of film thickness at molecular and nanometric scales by the sequential deposition of multifunctional complementary materials via different types of intermolecular interactions. Additionally, the films are generally deposited from precursors in liquid solutions or suspensions onto a large variety of substrates of either planar or curved surfaces, from rigid to flexible materials. These features make the LbL technique very affordable in terms of cost and ease of execution and it can be applied to virtually any type of material. The present manuscript provides a comprehensive review of photo-induced devices for energy conversion and environmental remediation based on LbL films composed of photoactive/photocatalytic nanomaterials. Its main goal is to give to a general readership the fundamental aspects of film assembly via the LbL technique, a detailed description of the different film nanoarchitectures, and finally, the outstanding photochemical and photoelectrochemical performance of photo-induced LbL assembled devices. (C) 2017 Elsevier B.V. All rights reserved.