Kaushik Balakrishnan, PhD Research Summary 1 [email protected]Dimension and size control self-assembly of functional organic building blocks: New possibilities in organic materials and device technologies “0 D” “1 D” “2 D” “3 D” FROM MOLECULES TO MATERIALS • Synthesis: π-rich molecules (PDI, and BTDs) and macrocycles • Self-assembly: Size and Dimension control • Applications: Sensing, Optical, Energy and Display
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Dimension and size control self-assembly of functional organic building blocks: New possibilities in organic
materials and device technologies
“0 D” “1 D” “2 D” “3 D”
FROM MOLECULES TO MATERIALS • Synthesis: π-rich molecules (PDI, and BTDs) and macrocycles • Self-assembly: Size and Dimension control • Applications: Sensing, Optical, Energy and Display
Self-Assembly• Spontaneous organization of a component (building blocks) into
ordered structures using interactions (non-covalent, ionic, etc.) inherent of the component(s) in select environment (solvent, vapor, surface, etc.).
• The self-assembled structures possess unique properties (new function) specific to the nature of organization of the building blocks and are often distinctly different from those of the individual building blocks.
• The collective organization of the building blocks therefore allow for realizing structures larger than themselves - bottom-up construction tool.
• Ability to control dimension (0D, 1D, 2D, and 3D) and size of resulting structures.
Examples of self-assembly DNA structure, formation of crystals, etc.
100#nm#1#nm# 10#nm# 1#µm#1#Å#
Size of building blocks (e.g., molecules, polymers
Self-Assembly of PTCDI*PTCDI’s#exhibit#unusual#proper5es#like#•#High'absorbi9viy'and'fluorescence'yields''•'Thermal,'chemical'and'photochemical'stability'
Highly efficient molecular stacking Such ideal stacking is difficult to achieve because of side-chains association and energy balance by optimizing the lateral, and transverse offset
A- Dispersion - Rapid approach injection of components into ‘poor’ solvents B- Phase-transfer: Slow diffusion of molecules from ‘good’ to ‘poor’ solvents C - Phase transfer at high temperature: Controlling the rate of diffusion by improving solubilityD- Gelation: Coercing components to maximize molecular interactions (useful in non-planar systems) E - Vapor phase treatment: Another slow diffusion process to control size, and shape of assemblies
Controlling nature, and size of functionalization (i.e., side-chain) enables influencing solubilities and using the solution processing toolkit allows for controlling size, and shape of resulting assemblies. In turn this allows for fine tuning optical and electrical characteristics.