Photosensitive materials are substances that change their properties when exposed to light. These materials can be found in various applications, such as photography, where they help capture images on film, and in electronics, where they are used in devices like solar cells. When light hits a photosensitive material, it can cause chemical reactions or physical changes. For example, in photolithography, a process used in semiconductor manufacturing, photosensitive materials help create intricate patterns on surfaces. This ability to respond to light makes them essential in many modern technologies.