Quantum dots (QDs), which are also known as semiconductor nanocrystals, have been widely applied in the design and development of photoelectric detectors and solar cells because of their low manufacturing cost and unique optical properties. The synthesis of QDs is an important component in the preparation of photodetectors and solar cells. In this review, several different QD synthesis technologies, various QD-based photodetectors and solar cells are summarized, and the advantages and disadvantages of different types of QD films are compared. Lastly, we investigated the development of QD films.