Perovskite solar cells, specifically using SnO2 nanoparticles, have been extensively researched and are proving to be extremely promising in the field of renewable energy by increasing a solar cell's overall efficiency and lowering the cost of production. In this study, an experiment was performed to synthesize SnO2 nanoparticles over 8 days. Day 1 was the synthesis which included the mixing of water, tin (II) chloride, methanol, sodium carbonate and dimethylformamide and then heated in a water bath at 28 . Sampling of this solution started on day 4 of the experiment when sufficient particle growth was observed and stopped at day 8. Centrifuging, freezing, and freezedrying were used for each sample to isolate the solid product. Transmission electron microscopy and X-ray powder diffraction was used to characterize the isolated nanoparticle. The results from the X-ray powder diffraction showed that each sample consisted of SnO2 nanoparticles of different sizes. From the transmission electron microscopy on the samples showed that the overall size of the nanoparticles gradually increased during each additional synthesis day.

TiO2 nanoparticles are often used as a photoanode material in dye-sensitized solar cells. Sintered together, the TiO2 particles are often conducted at 500℃, to provide porous TiO2 thin films. Anatase TiO2 nanoparticles with the dimensions of around 20-30 nm are routinely used to facilitate better electron transport and high dye-adsorption capacity in the film. Prior experiments on the solution synthesis of TiO2 suggested that dimethylformamide (DMF) plays a crucial role in the formation of DMF-containing amorphous TiO2 precursors in solution, adaptable for creating size-controlled TiO2 nanoparticles in the following high temperature process. It was observed that subsequent sintering process of the precursor at 500℃ produced Anatase TiO2 nanoparticles with the sizes of around 20 nm. The purpose of this research is to discover a method of obtaining Anatase TiO2 semiconductor nanocrystals using low-temperature process without using a high temperature oven. The amorphous TiO2 precursors were prepared at 40℃ using an aqueous TiCl4 solution as a Titanium compound and DMF as a structure directing agent. A new method involved the creation of the semiconductor nanoparticles through freeze-dry the resultant TiO2 antecedents in order to produce a crystalline powder. The size, shape and crystal phase of TiO2 particles were also characterized using a transmission electron microscope (TEM) and X-ray diffraction (XRD). It was found that Anatase nanoparticles formed with freeze-dry process of amorphous TiO2 precursors. This allowed us to produce crystalline TiO2 at a low temperature.