AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
A Versatile Aerosol-based Technique to Deposit Nanoparticle Thin Films from Colloidal Solutions
SHALINEE KAVADIYA, Jonathan Bryan, Yuji Okamoto, Peter Firth, Hussain Saddam, Zachary Holman, Arizona State University
Abstract Number: 817 Working Group: Nanoparticles and Materials Synthesis
Abstract Nanoparticles have revolutionized many industries in the past few decades because of their small size and high surface area to volume ratio. Many of the fields, from healthcare to food manufacturing and energy conversion and storage, require nanoparticles to be deposited as a functional thin film that maintains or even enhance the functional properties of the material. Nanoparticles are conventionally synthesized using wet-chemistry methods, resulting in a colloidal solution or dry powders. A variety of techniques are currently present to deposit these particles on a surface, namely, spin coating, spray technique, ink-jet printing, evaporation, plasma-based printing, sputtering, etc. However, these techniques are either not versatile or do not have precise control.
Therefore, the aim of this work is to develop a versatile technique, Aerosol Impaction-Driven Assembly (AIDA) to deposit a nanoparticle thin film on any kind of substrate with control over the film properties. The technique involves a two-step spraying process. In the first step, a colloidal solution of nanoparticles is sprayed through an ultrasonic atomizer nozzle in a low-pressure chamber (1-50 Torr) generating droplets containing nanoparticles. The droplets are carried with a carrier gas and solvent from the droplets is evaporated. In the second step, the nanoparticles are passed through a fine orifice nozzle along with a carrier gas into a deposition chamber with much lower pressure (0.1-5 Torr). The large pressure ratio (10-fold) accelerates the nanoparticles to supersonic velocity, creating a spray of nanoparticles. The low pressure downstream of the nozzle reduces the drag force on the nanoparticles and enables them to deviate from the gas stream and impact on a substrate, forming a thin film rather than flowing away along with the carrier gas. Using this technique, a thin film can be deposited conformally on any type of substrate, from planner Si wafer to a textured wafer. Dry deposition of 50 nm silver particles is achieved, and a uniform coating of a thin film is in progress.
The presentation will discuss the mechanism, challenges, and applications of this technique.