The major difference between the third-generation solar cells and the previous generations is the introduction of organic compounds and nanotechnology in the manufacturing process. Previous generations include photochemical solar cells, dye-sensitized solar cells, polymer solar cells, and nanocrystalline solar cells. A special multilayer thin-film structure has also been introduced to improve light absorption efficiency in the solar cells.  Perovskite is a new synthetic photovoltaic material. Due to its excellent photoelectric conversion rate, natural abundance, low cost, and environmentally friendly production, perovskite has quickly become a hot research area in the solar energy industry.