Photo-reactive

Photo-reactive describes a substance, material, or system that undergoes a chemical or physical change in response to the absorption of light (photons). This response can manifest as changes in color, shape, structure, or chemical composition. The effect is directly related to the light's intensity, wavelength, and duration of exposure. These photo-reactive properties are frequently employed in various technologies, including photography, light-sensitive pigments, and medical treatments. They can be engineered by incorporating specific molecules into materials that are designed to absorb and react to specific regions of the electromagnetic spectrum. This characteristic allows for control over the material's properties through controlled illumination.

Photo-reactive meaning with examples

• The scientist developed a photo-reactive coating for solar panels. It increased efficiency by adjusting its absorption spectrum based on sunlight intensity. The coating darkens in intense light to prevent overheating and lightens in low light to absorb more energy, maintaining a consistent energy output.
• Researchers investigated a photo-reactive dye that changes color when exposed to UV light. This color-changing dye was then used to create novelty items. The dye’s properties, changing from a vibrant color to transparent and back again, were harnessed for creating toys and other products.
• Doctors employed photo-reactive drugs in photodynamic therapy to target cancerous cells. The drug is injected into a patient and is activated only when exposed to a specific wavelength of light. The light selectively destroys cancer cells, limiting damage to healthy tissue.
• The architect specified photo-reactive glass for the building’s facade. The glass darkens in bright sunlight to reduce glare and heat gain. This property helps maintain a comfortable internal environment and reduces energy consumption for cooling during hot days.