Perovskite Nanocrystal Self-Assemblies in 3D Hollow Templates

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Highly ordered nanocrystal (NC) assemblies, or superlattices (SLs), offer unique properties for optical and optoelectronic devices.
• Lead halide perovskite NC SLs exhibit extraordinary optical characteristics and collective emission processes like superfluorescence (SF).
• Current drying-mediated self-assembly methods lack control over SL position and size, hindering device integration.

Purpose of the Study:

• To demonstrate a template-assisted self-assembly method for deterministic placement and controlled geometry of perovskite NC SLs.
• To enable the integration of perovskite NC SLs into device structures like photonic waveguides and microcavities.
• To investigate the influence of SL geometry on collective optical effects.

Main Methods:

• Utilizing lithographically defined hollow structures as templates on a substrate.
• Drop-casting a solution of CsPbBr3 NCs onto the templated substrate.
• Solvent evaporation and removal of excess NCs to leave NCs confined within the templates, defining SL position and size.

Main Results:

• Successfully demonstrated template-assisted self-assembly for controlled perovskite NC SL formation.
• Observed signatures of superfluorescence (SF) in the deterministically assembled NC SLs via photoluminescence (PL) measurements.
• Established a method to precisely control the position and geometry of NC SLs.

Conclusions:

• Template-assisted self-assembly provides precise control over perovskite NC SL placement and geometry.
• This technique is crucial for developing optical devices incorporating perovskite NC assemblies.
• Enables fundamental studies on tailoring collective optical effects through superlattice geometry.