Layer-by-Layer Nanoassembly of CIS Nanoparticles

Copper Indium Selenium (CIS), due to its tunable wide band gap, has been widely studied for photovoltaic applications. In this work, CIS nanoparticles have been fabricated and functionalized with poly(sodium-4-styrene sulfonate) (PSS) and/or poly-allylamine hydrochloride (PAH), which allow them to disperse in aqueous solution. The resulting aqueous dispersion of CIS nanoparticles have subsequently been used to construct thin multilayer CIS films on flexible substrates using Layer-by-Layer (LbL) nanoassembly process. LbL nanoassembly is a cost-effective process that allows construction of composite nanoscale multilayer coatings of oppositely charged polyelectrolytes, nanoparticles and/or other nanomaterials. The results from Quartz Crystal Microbalance (QCM) show that the CIS nanoparticles with other polyelectrolytes, such as PSS and PAH, can be used to deposit thin films of controlled nanometer range thickness using LbL process. The utilization of the developed LbL based CIS films in solar cell fabrication is currently in progress.