Nanostructured thin films synthesis using Aerosol Chemical Vapor Deposition(ACVD) for solar cells and batteries
ACVD is a scalable, atmospheric pressure, single step process for the synthesis of nanostructured thin films with a high degree of control over the film morphology and the crystallinity. This process enables the synthesis of single crystal one dimensional thin films of metal oxides and mixed metal oxides. Due to their excellent electronic properties and one dimensional nanostructure, these thin films find tremendous applications in solar energy harvesting and storage. Devices include perovskite, biohybrid and dye-sensitized coupled metal-oxide-semiconductors for solar PV, and solar to fuel conversion via photoelectrochemical water splitting or via CO2photoreduction. Metal oxide thin films are also used as additive-free lithium ion battery electrodes for energy storage. The thin film electrodes exhibit excellent electrochemical performance with reduced capacity fade, due to their single crystal and oriented nature
Synthesis of alternative transparent conducting oxide material using Flame Aerosol Reactor (FLAR)
There have been significant efforts focused on finding suitable and cost effective alternatives to indium tin oxide (ITO), a transparent conducting oxide (TCO) material due to increasing material costs. However, alternative TCO materials, produced using low cost and scalable methods, has yet to be achieved. A flame aerosol reactor (FLAR) provides a viable option for the production of TCO thin films. Flame aerosol synthesis of oxide nanomaterials is asingle step, scalable technique for the synthesis of materials and has been used in the production of single component, nanostructured thin films of TiO2. The ability to utilize this fabrication method for doped nanomaterials has been limited in part due to a lack of fundamental understanding of multicomponent particle formation in flame aerosol reactors. Towards the goal of extending this technique to multicomponent systems, a FLAR was used to deposit thin films of TCOs. By controlling various process parameters such as the deposition height and precursor feed rates, the influence on the thin film performance characteristics and morphology were studied. Various electrical and optical characterization methods will be performed to understand the optical properties and conductivity mechanisms.
Nano-biohybrid solar cell and water splitting
Nano-biohybrid solar cells utilize natural light harvesting complexes in artificial systems to convert sun light into chemical energy. Photosystem I (PSI) and Photosystem II (PSII) are the two main protein complexes of the natural photosynthesis process. These systems are used as sensitizers in photoelectrochemical solar cells, thus mimicking the natural photosynthesis process in artificial systems and producing hydrogen and oxygen by water splitting. Electrospray, an aerosol route, is used to deposit these complexes. Electrospray provides precise control over the assembly of the protein complexes and makes it possible to deposit them directly on the electrode. Such biohybrid solar cells have the advantage of avoiding the use of toxic chemicals but still providing significant energy conversion.?
Kinetics of silicon dust formation and kerf recycling
The high cost of silicon solar cells limits their economic viability. The high expense is driven by the manufacturing process, which is highly inefficient. More than 40% of the total initial ultrapure silicon goes into waste called kerf during the slicing of silicon ingots to manufacture wafers and it is challenging to recycle them. Here, we try to optimize an aerosol process for kerf recycling and eliminate all the carbon present in kerf without oxidizing the silicon fraction. Another area for cost reduction is the use of fluidized bed reactors, instead of Siemens reactors, in the chemical vapor deposition (CVD) process for silicon refining from silane gas to polysilicon. Fluidized bed reactors (FBR) are a complex but cheaper alternative. Our goal is to develop a better understanding of silane FBR CVD process to predict optimum operating conditions and to enable more reliable reactor scale-up.?