Prof. Peter Kralchevsky

Two-dimensional and multilayered colloid crystals with optical and photonic applications

Тhe lateral capillary forces between particles at liquid interfaces bring about particle aggregation and ordering, and play an important role in the production of various two-dimensional (2D) and multilayered structures, with numerous optical and photonic application (see the Introduction). The contributions of the Group in the field of capillary forces and colloidal crystals have been recently reviewed.1-4 In particular, it was established that the interactions between capillary multipoles can be strong enough to induce formation of interfacial colloidal crystals from nanoparticles.5,6 The single-particle and two-particle problem was investigated in details for the case of electrically-charged particles that form non-densely packed 2D colloidal crystals.7-9 For formation of regular particle multilayers, the oscillatory-structural forces can be applied, for which excellent agreement between theory and experiment was recently achieved.10,11

Future plans: First, external electric an magnetic fields, perpendicular to particle monolayers at a liquid interface, will be used to achieve a fine tuning of the interparticle distances. This will allow to create 2D colloidal crystals of controllable optical and photonic properties, and to create interfacial pattern (colloidal display) by using non-uniform and variable external fields. Second, the colloidal structural forces and the external fields will be employed to create nanoparticle multilayers of controllable thickness for optoelectronic and photonic applications. To achieve the formulated goals, both experimental studies will be carried out and quantitative theoretical models will be developed, which will allow us to interpret the experimental data, to predict and engineer the properties of materials with other nanoparticles and systems by computer modeling.