Engineering the Electrostatic Interactions between Oppositely Charged Polymer-Grafted Nanoparticles for Constructing Colloid Molecules on Substrates

Arrays of nanoparticle (NP) clusters with controlled architectures show broad applications in nanolasers, sensors, and photocatalysis, but the fabrication of these arrays on substrates remains a grand challenge. This review presents a highly effective polymer-based strategy for the process-directed self-assembly of binary polyelectrolyte-grafted NPs (PGNPs) bearing opposite charges into stable colloidal molecules (CMs) on substrates via electrostatic interactions. The coordination number (x) of AB(x) CMs can be tuned by adjusting the pH or ionic strength of the solution or by employing different combinations of PGNPs with varying charge densities. Large-area CMs with diverse structures ranging from AB to AB(7) can be constructed on substrates in high yields. This approach is applicable to PGNPs with different cores of NPs. This assembly strategy offers a useful tool for the fabrication of structurally precise assemblies on substrates with broad applications.