Anisotropic Nanoparticles: preparation process and their use as quantumdots in liquid crystals

KSU-336

Abstract: Semiconductor nanowires and rods own unique thermal, electric, optical and mechanical properties with great potential applications.  Many methods have been used to prepare Cadmium Sulfide (CdS) nanorods and nanowires, including vapor-liquid-solid, thermal evaporation, template, aqueous-solution, hydrothermal, solvothermal, PVP fiber matrices by electrospinning, etc. Lyotropic columnar LC materials can also act as growth medium to optimize size and shape of semiconducting nanorods.  But there still remains need to reduce costs of the particle synthesis by further simplifying methods. We disclose a cheap, easy and controllable preparation of CdS nanoparticles with anisotropic shapes.  Particularly useful of those particles seem to be the rod-shaped particles with an average length  less than 50 nm and diameter in the range of  2-10 nm.  This invention employs surfactant-water systems which provide a simple way to vary the ratio of slenderness (length/diameter).

Applications:

•          Solar cell architectures, nanolasers, computational technology
•          Optical switches, filters
•          Integrated photonic devices and many other chromogenic smart devices
•          Power-conserving LCD devices, such as reflective displays with auto shut-off in insufficient ambient light
•           Intensity-controlled switchable windows, traffic lights using reflective LC panels, etc.

Advantages:

•          Uses the mature liquid crystal display technology for other nanomaterials and new possible applications
•          Easy and controllable preparation of cadmium sulfide nanoparticles with anisotropic shapes
•          Low cost and widely useful
•          Makes possible a simplified spatial light modulator containing only an ITO, LC, and CdS layer

 Inventors: Dr. Antal Jakli (Kent State Univ.); and Dr. Attila Bota et al (Inst. Chem. Hung.Acad.Sci.)