Macroscopic Nanotemplating of Semiconductor Films with Hydrogen‐Bonded Lyotropic Liquid Crystals

Abstract

Aqueous gel‐like lyotropic liquid crystals with extensive hydrogen bonding and nanoscale hydrophilic compartments have been used to define the growth of macroscopic nanotemplated CdS and CdTe thin films. These mesoporous semiconductor films contain a hexagonal array of 2.5 nm pores, 7 nm center‐to‐center, that extend in an aligned fashion perpendicular to the substrate. The CdS is deposited on a polypropylene substrate by a reaction between Cd(NO3)2 dissolved in the liquid crystal and H2S transported via diffusion through the substrate. The CdTe is electrodeposited on indium‐tin‐oxide‐coated glass from TeO2 and Cd(NO3)2, both of which are dissolved in the liquid‐crystal template. The porous nature of the CdTe films enables chemical transformations of the entire bulk of the film. As electrodeposited, the CdTe films are Te rich and, in contrast to a non‐templated film, the excess Te could be removed via a chemical treatment, proving the continuity of the pores in the nanotemplated films. These results suggest that liquid‐crystal lithography with hydrogen‐bonding amphiphiles may be a useful approach to create materials with nanoscale features over macroscopic dimensions.

Synthesis, characterization and magnetic properties of hematite (α-Fe2O3) nanoparticles on polysaccharide templates and their antibacterial activity

“…Aqueous gel-like lyotropic liquid crystal with extensive hydrogen bonding and nanoscale hydrophilic compartments can be employed for direct templating of nanoscale features (Braun et al 2005). The use of biological materials as templates is gaining momentum and biotemplating takes advantage of the structural stability and specificity of biological systems to create novel materials (Sotiropoulou et al 2008).…”

Templated electrosynthesis of nanomaterials and porous structures

“…Similarly, palladium and rhodium films containing regular arrays of uniform pores were obtained by electrochemical deposition from H 1 non-ionic lyotropic liquid crystal phases [32,33]. Stupp and co-workers [34] used oligo(vinyl alcohol) 16 oleyl ether-based hexagonal lyotropic liquid crystal as templates for the electrochemical growth of CdTe semiconductor films. The pores of deposited films were in a hexagonal array with a diameter of 2.5 nm and a centre-to-centre distance of 7 nm and in an alignment perpendicular to the substrate.…”

“…Hexagonal phases consist of aligned cylindrical micelles in a hexagonal array, whereas cylindrical micelles in cubic phases are interconnected on a gyroid lattice and lamellar phases consist of lamellar structured micelles. The hexagonal phases of lyotropic liquid crystals have been employed as templates for electrosynthesis to form hexagonally mesoporous materials [31][32][33][34].…”

Synthesis of aligned hematite nanoparticles on chitosan–alginate films

“…Aqueous gel like lyotropic liquid crystal with extensive hydrogen bonding and nanoscale hydrophilic compartments can be employed for direct templating of nanoscale feature [1]. In this, the use of biological materials as templates is gaining importance.…”