The document discusses the history, types, structure, and working of solar cells. It covers: - The photovoltaic effect was first discovered in 1839 by Edmond Becquerel. - The main types of solar cells are amorphous silicon, concentrated photovoltaic, and crystalline silicon. - A solar cell uses sunlight to generate electricity, requiring the absorption of light to raise electrons to a higher energy state and the movement of electrons through an external circuit. - Research areas include nanocrystalline solar cells, thin film processing, and multijunction solar cells to improve performance and lower costs.